Designer:
Eric L. “brkitup”

Project Category:
Bookshelf Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Simplicity is a two-way bookshelf loudspeaker system using Dynavox and Dayton drivers, and knock-down flat-pack speaker cabinets.

Design Goals:
The goal of this project was to make a high-performance bookshelf speaker that could handle decent power, was simple in design and construction, and would provide exceptional sound quality for the money.

Driver Selection:
I’ve always wanted to use a Dynavox driver, so when the new series was introduced, I knew it was time to pull the trigger. I ended up choosing the Dynavox LW6004HR-N (295-626) 6.5″ woofer for its fairly smooth response and roll-off characteristics, and also because it’s gorgeous to look at. For the tweeter I chose the Dayton ND28F-6 (275-040), which is a proven performer and a great value.

Enclosure Design:
The enclosure is the .56 cu. ft. Denovo flat-pack speaker cabinet. These are CNC-cut, which makes construction quite simple. The Dynavox woofers are fairly high-Q units, and therefore work well in moderately-sized sealed enclosures. Calculations revealed the woofers would have an F3 of 66Hz, which is quite good for a sealed alignment.

Enclosure Assembly:
Enclosure assembly was a simple affair. I used a combination of wood glue, brads, and clamps during construction. Because the enclosure panels were pre-cut, a lot of time was saved in the assembly and construction process.

Crossover Design:
I enjoy using drivers with smooth roll-off characteristics in their frequency response, because it greatly simplifies crossover design. Because both the Dynavox woofer and Dayton tweeter were so well-behaved in this regard, I was able to use a simple 2nd-order Linkwitz-Riley alignment, and achieve excellent results. The woofer already has a slight downward-sloping response that was increased by using a slightly higher than required inductor on the woofer. This caused the response to slope downward slightly more, which is useful for correcting what’s known as “baffle-step”, and allows the speaker to produce more even frequency response when placed in a room. The crossover point I chose was 3 kHz, which places very little stress on the tweeter, and also works well for the Dynavox woofer.

Tips & Tricks:
I used a textured spray paint for the finish, but veneer would work also. To protect the tweeter I used the Visaton speaker grill (292-526) that was designed for 2.5″ speakers. It works perfectly for covering the tweeter, especially if you choose not to flush-mount. It is recommended that you use some sort of “fill” in the enclosure to minimize standing waves. I recommend using egg-crate style foam.

Conclusion:
This project exceeded my expectations. I wanted to create an economical bookshelf speaker that sounded good with a wide range of music. What I ended up with is the best speaker I’ve built thus far.

About the Designer:
I am a stay-at-home foster father, and have been building speakers for twenty years. I am also the sound engineer for The Foundation Church in Norwalk, Ohio.

Project Parts List:

Designer:
ekprayog

Project Category:
Freestyle Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
Clapton is an amalgamation of technology and hand craftsmanship. Made using Burma Teakwood. 50 Watt per Channel TDA7492 amplifier was used to power this system.

Design Goals:
Built with Dieter Rams philosophy of Less, but Better. The controls are as simple as they could ever be, which makes the intention of the system very clear. An On/Off toggle switch, a power jack and a 3.5mm AUX input.

Driver Selection:
Dayton Audio PS95-8 3-1/2″ Point Source Full Range Driver 8 Ohm
295-349

Enclosure Design:
Enclosure was made using 15mm thick Burma Teakwood with internal bracing using 1″ x 0.5″ braces. It’s ported at the bottom using a 1-3/4 ” dia port tube.

Enclosure Assembly:
Enclosure includes 14 pieces.

Conclustion:
The build was a lot of fun as this was my 5 unit. And it ended up looking really minimal and clean.

About the Designer:
I’m an Industrial Designer and a Mechanical Engineer with a lot of interest in music.

Designer:
hongrn

Project Category:
Loudspeakers/Cabinets

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
The Vintages are a 3-way design using the Dayton Designer Series DS270-8 10” woofer, the Dayton DC50FA-8 closed back midrange, and the Beston RTA002A ribbon tweeter.

Design Goals:
Remember the speakers of the seventies? Remember those monkey coffins? My overall goal is to replicate the same design approach – wide baffle, recessed grill – using drivers that seldom appear in DIY projects on the Tech Talk Forum.

Driver Selection:
1. I selected the Designer Series woofers due to their good looks, small box requirement, good excursion and therefore good value.
2. The DC50FA midrange, re-designed a while back, seemed forgotten as I don’t see many designs using this driver, except for Paul Carmody’s Classic Revival. The published frequency response is fairly flat, with a SPL of 89dB, closely matching that of the woofers.
3. The Beston RT002A is intriguing to say the least, a ribbon tweeter in a waveguide that only costs $42.

Enclosure Design:
Box was modeled in BassBox, tuned at 28Hz with a F3 of 30Hz. Box Volume is 3.3 cu.ft, external dimensions are 30” H X 21” W X 12” D, and Vent dimensions are 2.75” in diameter by 4” long.

Enclosure Assembly:
Nothing difficult to report as this is a box comprised of flat pieces of ¾” MDF assembled together and braced using Titebond wood glue. The vent is Home Depot black plastic plumbing pipe. For the grill, I glued and stapled grill cloth over a ½” MDF frame. Half inch neodymium magnets (also Home Depot) are used to keep the grills in place. Real cherry veneer was used to cover all MDF surfaces. The baffle is ¾” birch plywood reinforced with ½” MDF, so the total thickness is 1.25”. The black part of the baffle was masked with Frog Tape, sprayed with gray primer, sanded, then finished with several coats of black “hammered” Rust-Oleum.

Crossover Design:
All measurements were made with the drivers mounted in box, with a calibrated mic positioned 1 meter away, on-axis with the tweeter. I use FRD Response Blender, WinPCD, PCD and ARTA to design and measure. ZMA files were generated using DATS, and FRD files using ARTA. Driver acoustic offsets were determined using WinPCD.

Crossover points are 600Hz/4,000Hz. I used a 2nd order electrical on the woofer, 3rd order on the tweeter, 3rd on the mid’s high pass, and 2nd on the mid’s low pass. This resulted in a 2nd order Butterworth on the woofer, 4th order BW on both the tweeter and midrange. Mostly inexpensive crossover components were used, including I-Core inductors to keep DCR low.

Frequency response is flat within +/-2.5dB, while phase tracking is more than satisfactory. Impedance drops to only 4.15 ohms between 2 and 3KHz, so these speakers shouldn’t stress any amplifiers out there. Off-axis response is remarkable, as very little drop off was measured when one moves away from the center. Even at 45 degrees, the tweeter’s waveguide did its job nicely.

Tips & Tricks:
1. Because of the total number of crossover components (13), I elected to put them on 2 different boards to minimize wiring errors.
2. If you have access to measuring gear, such as DATS, hook up your drivers and perform a quick impedance sweep after wiring the crossover to identify any errors.

Conclusion:
This was one of my most satisfying projects. 3-ways are so much more complex to model, and this one is no exception. I virtually spent two weeks in front of the computer screen trying to coax these drivers for the optimum crossover points, the flattest frequency response they will allow, adequate phase tracking, and an impedance that won’t clip any amplifier. After 9 versions of the crossover, everything came together in a very good sounding package: the sound is crisp and detailed without any harshness, with an amazingly wide soundstage. Whether the track is instrumental or vocal, the mid comes through cleanly and competently. Bass is loud and clean, and the waveguide ribbon tweeter really shines. When implemented correctly, these high value drivers can more than deliver and keep up with high resolution digitally mastered tracks. I kept saying to myself that one of these days, I’d have to build a “cost is no object” system us ing some of the most expensive drivers out there. Cross that off my bucket list…

About the Designer:
Hong Nguyen is a registered nurse by training, and is currently employed by a healthcare company specializing in the management of ambulatory surgery centers. He was a member of the 2016 Speaker Building Design Team.

Project Parts List:

Designer:
John H

Project Category:
Bookshelf Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
This project uses the BR-1 cabinet and the Dayton DSA-175 woofer. The BR-1 cabinet pair is available separately which makes this project easy to accomplish as no cabinet building or finishing is required.

Design Goals:
The design goal was to make something that would both sound and look good that could be accomplished with minimal woodworking skills.

Driver Selection:
The project started in reverse as the BR-1 cabinet was selected. With the improved motor and surface mount face plate the DSA-175 woofer was a good fit for this project. The original DC28F-8 turns out to be the best choice to match the quality of the DSA woofer and fit in the cabinet.

Enclosure Design:
Each BR-1 cabinet is 15 liters. With the DSA175-8, the bass response results in an F3 of 41 Hz with a box tuning of 45 Hz. The stock port is to small so it was removed by tapping it out from the inside or you can drill it out with a hole saw. The new port hole was cut by first drilling a 2 3/8-inch hole through a piece of scrap plywood then clamping this template to the box over the old port hole. This keeps the hole saw centered and minimizes damage to the vinyl covering.
The new port tube has a sliding outer sleeve for adjusting the port tube length. This sleeve is glued in the closed position then cut to length. The port tube length is 6-inches measured from the inside of the port tube.

Enclosure Assembly:
There’s not much assembly, but the woofer mounting holes need to be predrilled. Set the DSA175-8 in the woofer cut out. You will notice that the woofer overlaps the tweeter hole. Rotate the DSA175 so one mounting hole is at the middle bottom of the cabinet. This will keep the screw holes away from the tweeter.

Center each of the DSA175 mounting holes at the edge of the woofer cut out on the cabinet. Mark the location of the mounting holes on the edge of the cut out. To get the DSA175 mounting screws to go in straight, drill a small diameter pilot hole at the edge of the cut out. Using progressively lager drill bits to expand the top of the pilot hole such that a recess is made into the edge of the woofer cut out for the DSA175 mounting screw.

Assembly starts with the port tube. After drilling the hole for the port tube, predrill pilot holes for the port tube, add a small amount of wood glue around the port hole to seal any air leaks, screw the port tube to the box.

The leads and connectors for the power in, woofer, and tweeter should be attached to the crossover board. If you are using crimp on connectors, slightly squeeze the back half of the connect so there is a tight fit on the spade terminals at the terminal cup, tweeter, and woofer.

Mount the crossover on the bottom of the box. Unscrew the terminal cup and connect the power “in” leads between the terminal cup and the crossover. Add a small amount of glue around the terminal cup hole (to seal any leaks) and screw the terminal cup back in place.

The crossover board can be attached to the box with a small screws, hot glue or other glue.

Add about 4 oz. of Acousta-Stuf Polyfill Speaker Cabinet Sound Damping to the back of the cabinet below the port tube. Keep the insulation away from the back of the woofer by an inch or more. You can use poly batting to hold the insulation away from the woofer by stapling to the cabinet sides or by pushing the batting behind the bracing and crossover.

Attach the leads to the tweeter and screw the tweeter into the cabinet cutout. Add two layers of 1/8 by 3/8- inch speaker gasket tape to the woofer recess cut out in the cabinet. Attach the leads to the DSA175 woofer and screw the woofer to the cabinet. Be careful not to over tighten the woofer screws.

Crossover Design:
The crossover was designed for flat frequency response with the grill on. All the measurements were done with the grills in place however, the speaker sounds great without the grill for those who prefer that look.

Based on the distortion of the DC28F, and matching of the driver phase, the fit best is a crossover at about 1,900 Hz. with Linkwitz Riley 4th order slopes.

The crossover part layout drawing is just a suggestion, there is plenty of space in the bottom of the cabinet for a larger layout.

This crossover was assembled on a 4 x 4.5-inch board. Wire ties and hot glue hold the components to the board.

The measured impedance stays above 6 ohms

Tips & Tricks:
The cabinet could benefit from a bit more bracing or thickening of the side and top panels, although none were used here.

The tweeters are offset and should be positioned toward the inside/ other speaker. Use a black magic maker to touch-up any flaws in the cabinet.

Conclusion:
The BR1 cabinets look good for the money. Combining the cabinets with the new DSA175 woofer and raising the DC28 crossover point a bit higher results in a very nice sounding speaker.

About the Designer:
John is a member of the speaker design team.

Parts Used:
295-528 Dayton Audio DSA175-8 6-1/2″ Designer Series Aluminum Cone Woofer 2
275-070 Dayton Audio DC28F-8 1-1/8″ Silk Dome Tweeter 2

260-317 Acousta-Stuf Polyfill Speaker Cabinet Sound Damping Material 1 lb. Bag 1
260-540 Parts Express Speaker Gasketing Tape 1/8″ x 3/8″ x 50 ft. Roll 1
090-830 NTE European Terminal Strip 25-E2000 12-Pole 20A 1
101-786 Consolidated 16 AWG 2-conductor Power Speaker Wire 25 ft. (Red/Black) 1
095-282 0.205″ (16-14) Female Disconnect Crimp Terminal Blue 50 Pcs. 1
260-387 Speaker Cabinet Port Tube 2″ ID Adjustable 2
300-645 Dayton Audio BR-1CAB BR-1 6-1/2″ 2-Way Speaker Cabinet Pair 1

004-10 Dayton Audio DNR-10 10 Ohm 10W Precision Audio Grade Resistor 2
004-20 Dayton Audio DNR-20 20 Ohm 10W Precision Audio Grade Resistor 4
266-560 ERSE 3.5mH 18 AWG I Core Inductor Crossover Coil 2
255-040 Jantzen Audio 0.60mH 20 AWG Air Core Inductor Crossover Coil 2
266-800 ERSE 0.10mH 18 AWG Perfect Layer Inductor Crossover Coil 2
027-426 Dayton Audio DMPC-8.2 8.2uF 250V Polypropylene Capacitor 2
027-421 Dayton Audio DMPC-4.0 4.0uF 250V Polypropylene Capacitor 2
027-400 Dayton Audio DMPC-0.10 0.10uF 250V Polypropylene Capacitor 2

Designer:
Park

Project Category:
Bookshelf Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
I had purchased a pair of B stock Zu Cubes from Sean at Zu Audio awhile back. I like them, but thought I could improve on the sound quality and still use similar parts. My littlest son also need a set of speakers for a 3116 chip amp too.

Design Goals:
Clone the Zu Cube in dimensions, parts, and clean up the response curve. I got help from an owner of a speaker manufacturer from Texas (curves and xo).

Driver Selection:
Eminence Beta 10 CX 10 Inch Coax driver 290-502
Eminence ASD 1001 1 Inch HF Horn Driver 290-525

Enclosure Design:
Straight copy of the 10.5 inch cubed box, 3/4 inch left over material, coated with Dura Tech black, and loaded with damping material.

Enclosure Assembly:
Super simple, cut all the squares the same dimensions, outside dimension are 10.5 inch cubed.

Crossover Design:
The current Zu XO consists of a single inline cap to roll off the tweeter. This is 1.0 uf cap. A true xo can even out the frequency response significantly.

Conclusion:
I had a good time making these with my middle schooler. These are good book shelf speakers and need some lower end help or a subwoofer, but if you can get the parts for a reasonable price, they are much cheaper than 1K.

About the Designer:
I like to fix things and make them better, but not always cost effective…

Parts Used:

Designer:
Matt Ristrom

Project Category:
Loudspeakers/Cabinets

Project Level:
Advanced

Project Time:
1-8 Hours

Project Cost:
$500 – $1,000

Project Description:
Flame-thrower: Stackable line array speaker for med size indoor or outdoor pro audio use.

Built for Rocky Rude, a notable live audio engineer (and ESPN live video tech). Rocky really likes the look of the PRV’s with the aluminum wave guide and was hoping they would handle more bass than advertised. I was skeptical but the result is an amazingly loud, yet small, line array cabinet.

Design Goals:
1 – Line array physics: stackable, with all drivers coupling correctly.
2 – Very small cabinet
3 – Very high power handling
4 – Extremely high SPL for outdoor concert sound

Driver Selection:
4 x PRV Audio 8MR500-PhP-4 8″ Midbass Midrange Woofer 4 Ohm
4 x PRV Audio WG2-230Ti Two D230Ti Compression Drivers & Line Array Waveguide Package

Enclosure Design:
Sealed cabinet tuned to app. 100hz, 8″ mid-bass aligned vertically with speaker edges touching, horns aligned vertically with edges touching. Pole mount or stacking. Designed to be used with separate sub-woofer system to cover low end up to app. 140hz.

Enclosure Assembly:
3/4 plywood for baffle, 1/2 plywood for box. Glued and nailed. Epoxy added to all seams and corners after construction. Parts express HD stacking corners to allow ground stacking.

The next four cabinets will have added fly-supports for hanging.

Crossover Design:
100hz 2nd order high pass for 8″ mid bass speakers for extra protection as this speaker is designed to be bi-amped. Built in high pass capacitor was removed to allow lower bass.

1000hz 2nd order high pass filter used for horns for extra protection only as this speaker is bi-amped.

Tips & Tricks:
The PRV horn drivers are wider than the space I wanted to leave for the mounting screws. I keep the integrity of the cabinet I used a dremel tool to carve out two bowls in the inside mounting rail for the horn at the top of the cabinet. This allowed me to slide each horn into the cabinet and into position. CON: several horns may need to be removed to make a repair.

Conclusion:
This speaker actually out-performs several JBL, RCF and EAW products for indoor use because it is so good at focusing the sound energy on the crowd and not the walls. At 1250 watts RMS per cabinet it also provides enough SPL to keep up with much larger boxes.

About the Designer:
Matt Ristrom is the owner of Colorsound Recording Studio in DeSoto, Kansas. He has performed on guitar in Minneapolis and Kansas City and auditioned for the Red Hot Chilli Peppers in 1993. Matt is also the owner of RF Consulting LLC a company that has been installing cabling and providing IT support for telephone and computer networks since 1999. Matt has been building and designing speakers since the 80’s.

Designer:
TomZ

Project Category:
Freestyle Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
This project came about for one simple reason: my laptop computer speakers sound awful. This issue became clear during this past 2016 Midwest Audiofest while my wife and I were in the hotel room trying to relax before the next day’s speaker competition. Of course, we wanted a little music to listen to… so I turned on Pandora and found some smooth jazz, but all we had to play the music on was the built-in speakers on my laptop computer. Before the first song was finished, my wife said to me, “you’re at a speaker-building competition, but we’re listening to music on these lousy laptop speakers? They sound awful!!! I think she may have said it a little nicer than that, but that’s pretty much what she meant. Yes, I was humorously ashamed…we both agreed right there that this was unacceptable, and as a DIY’er and speaker builder, I had to do better.
I’ve actually been meaning to build something like this for the longest time: something that would be portable enough to take with us every time we travel, but with good enough sound to make me feel somewhat “at home” quality-wise. There are a few viable solutions already…Chris Perez’s ‘Tablet Cinema,’ and Paul Carmody’s ‘Sprite’ boombox come to mind as two well received choices. As I thought about it further though, I realized I wanted this sound system to have the added feature of having a rectangular opening as a ‘pass-through’ for a standard telescoping luggage handle, making it easy to transport while on a suitcase, and also acting as a handle otherwise.

Design Goals:
Basically, I wanted to build a portable sound system that was small, convenient to tote along on trips, and had good sound. Also, I wanted to make assembly, and its use as easy and simple as possible. I opted for the most basic setup I could design… A box, an amp, and a power supply. There are no LED indicator lights, no volume knobs, no buttons… you just plug in the input cable and the power supply and you’re off to the races. The sound source acts as the ‘preamplifier’ if you will. I almost always take my laptop on trips so we can see what there is to do in the area, access my emails, and — of course –check PE’s Tech Talk Board — so I always have a sound source to work from. An iPad or even a phone with a music App would work fine as a source as well, providing it has a 3.5mm stereo output and adjustable volume. Basically, I wanted this project to be simple and no-frills, but sound great.

Driver Selection:
Driver/Amp Selection:
I chose the ND65-4 driver because it’s really a wonder of technology… Vented, it’s able to reach to the mid 60 Hz range at respectable volumes, but still provide decent upper frequency response — good enough to preclude the use of a tweeter in this case.

The amp I chose is the TDA7492 amp board which can produce as much as 50 watts per channel at 4 ohms, and it will work with voltages from 10 to as high as 26 volts DC. Since we are using a common and affordable 12v power brick to power this with, the available output will be lower, and more in line with the ND-65’s power rating of 15 watts, but it should still have enough clean output to avoid distortion on the amp side.

Enclosure Design:
The box is constructed of 1/2” MDF for the front, back and sides. The top, bottom, and internal panels are 1/4” thick MDF. Using a few well-placed top-to-bottom dowel braces mostly eliminates any cabinet resonances. The box is stuffed moderately with pillow stuffing.
The vents available from PE are 4” long, but since this design calls for a 5” long vent, I just added a few rolls of ‘Gorilla Tape,’ (duct tape will work as well) extending the inside end of the vent by about an inch. To do this, cut a piece of tape long enough to stick to the inside of the vent tube for approximately one turn — sticky side facing out. Then add several rolls of tape, sticky-side in to add thickness and strength. If you do it right, the port will still pass-through the hole in the cabinet, but be sturdy enough to hold its shape.

Enclosure Assembly:
The enclosure is assembled mostly with wood glue. There are a few little pieces that make up the various parts of this enclosure, but if you do a few smaller glue-ups, waiting a few hours for things to set up, things really go together fairly easily. I glued up the handle pass-through first, then added the amp side panels, then the front box divider. Then I glued up the side panels to the rear port panels. While those pieces were gluing up, I machined the front baffle. These drivers are small and they need some breathing room to operate correctly. I also made some ‘breathing room’ for the driver as well as notched out a space for the hook up terminals.
Once those pieces had set for a day, I glued them all together on the bottom 1/4″ panel along with two small 1/2″ dowels to brace the cabinet and give the crossover something to mount onto. Then I caulked the interior seams with silicone caulking to make the cabinet air tight.
Once I put some pillow stuffing in the nooks and crannies, it’s time to glue on the top. I used Gorilla polyurethane glue for this last step since it expands as it cures, and serves to seal the cabinet well since we can’t reach the inside of the cabinet to caulk the seams once the top is glued on.

Crossover Design:
The LR circuit consists of a .27 mH coil with a 5.6 ohm 10 watt resistor in-line with the positive wire going to the amp. The resistor is glued to the coil with hot glue and the entire assembly is slid over each bracing dowel and secured with ample hot glue and a zip-tie. I experimented with various values for this circuit and even ran the system with no filter at all for awhile but eventually felt that it needed some attenuation of the mid frequencies and a little kick in the bass to get things sounding more listenable. This circuit lowers the level of the mid frequencies and boosts the bass a few dB eliminating the slight “shoutyness” and adding a bit of heft to the overall sound.

Wrapping up Construction:

I built two versions of this system, one with speaker grills and one without. The cabinet carpet I used from PE had no laytex backing on it. As I held it up to the light, I could see through it to a degree, so I put it over my mouth tightly and tried to blow air through it. To my surprise, there was very little restriction. I decided to cover one of my stereo speakers with the carpet and ask my wife if she could hear which speaker had the carpet over it. She couldn’t tell the difference, and frankly neither could I.
At that point I figured I could recess the drivers and use the carpet as driver covers. I had some spare window screen material from a recent window repair, so for added strength, I cut a few squares of it to epoxy over the two driver openings before adhering the carpet to the box. I like the look of it, and it offers some protection and durability to the project. I hit the corners with Rust-Oleum Painters Choice black paint so the light colored MDF wouldn’t show through the carpet. I used spray-adhesive from PE to adhere the carpet to the box. A medium coat on both pieces, letting it rest for several minutes before adhering proved to be a good method. Rounding the corners with a 1/2″ round-over added some pizzaz to the project and prevents the corners from getting dinged while the luggage gets banged around… check your suitcases, they do take a fair amount of abuse!
Personally, I like the ‘stealthy’ look of the all-carpet version, although I realize that some may want the more traditional looking box with the grills… They do add nearly $10 to the project, but they will offer good protection for the drivers and eliminate the need to recess the drivers. Additionally, they make the box look more like a speaker, which some folks may want. Either way, I can throw this in our car trunk and not worry about it getting damaged at all… that’s how I wanted it. I just put its power supply and 3.5mm audio cable in my laptop bag and off we go. You might want to mark your laptop power brick with tape so you know which is which.
If you do just cover the drivers with carpet, they will need to be recessed slightly so the surround doesn’t contact the carpet. The easiest way to do this is to use some scrap 1/2” MDF, roughly 3” x 3” and cut a hole in it big enough to mount the driver into as if it were a baffle that you would surface mount the driver in. Then trace the driver frame opening onto the main box in the correct position and remove that material. This will allow the driver to sit ‘inside’ the box a bit. I put a 1/2” roundover on all the outside vertical corners of this piece and gently rounded over the inner side as seen in the picture. You may also want to slightly sand the MDF on this piece to allow for good driver breathing. Use very small screws to mount the driver with and there should be no problems.
The amp can now be wired up and mounted in the amp compartment. I cut four 1/4″ long pieces of bic pen to provide a slight ‘standoff’ for the amp so it could have some air flow and wouldn’t be touching the rear of the amp box. The cover for the amp opening is where the modified binding post is mounted. This panel also has several holes drilled on the top and bottom to allow for some airflow for the amplifier.

Tips & Tricks:
As is usually the case with DIY, there was some ‘customization’ of parts to make this work. I took a PE Binding Post terminal and took the two actual binding posts out of it so I could add the 3.5 mm input as well as the DC input jack to power the amp. Holes for each need to be carefully drilled out, and it’s a good idea to throw on a little thread locking compound before tightening. You could machine the cabinet to accept these two jacks, but that would leave precious little material to work with, and one bump might break the thin piece of wood. I opted to ‘hack’ the inexpensive binding post terminal as a simple solution to this since it looks nice and ‘finished’ when installed. Be sure to size the DC power jack to the power supply you intend to use, observing proper polarity.
Also, since the port exit inside the cabinet aims directly at, and is fairly close to the rear of the driver, I chose to create an ‘air deflector’ for the driver to eliminate the chance for fast moving vent air to interact with the air modulating out of the vented pole of the speaker. My fix was possibly overkill, but I felt it may eliminate a potential problem. It’s basically a piece of plastic from a bottle arched over the rear of the driver magnet, secured with a zip tie.
If you choose to forgo the grills and hide the drivers under the carpet, make sure to install and test them out for air tightness and proper electrical connection before covering the driver openings with the window screen material and carpet. I also added a little denim insulation to the outside of the secondary baffles to lessen diffraction on this part of the baffle.

Conclusion:
I think the most unique feature of this design is probably the telescoping handle pass-through, which allows for this to be easily transported without worry. It’s fairly stealthy as well, which is also a good thing in my opinion. As a disclaimer, I should mention that I checked out all the luggage handles at my local Target to make sure that the opening on this project would fit any handle within reason; you should check your luggage first before cutting to see if slight adjustments may be needed.
Overall, I’m really happy with this project… we now have nice sounding tunes while we relax in our hotel room at the end of a long day, and it plays loud enough to get a call from the front desk if I’m not careful. It’s about time for this DIY’er!

About the Designer:
I’ve been dabbling in speakers since I was a teenager when I built my first set of speakers. Even as a kid I thought they sounded kind of awful… but I had been bit by the bug — and have been striving for better sound and more creative cabinet designs ever since.

Project Parts List

Designer:
Andrew Hudson

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
This is my first speaker build. I have modeled my design off Scott Hinson’s published DIYRM-A design. The NWS is for “no woodworking skills”. I loved everything about Scott’s design, but I did not have the time, tools or the patience to fabricate my enclosures from scratch like he did. I selected the Dayton Audio, 0.283 ft^3, curved cabinets in piano black (P/N 302-701).

Design Goals:
• A small, sealed (acoustic suspension), bookshelf speaker
• A high WAF (wife approval factor)
• An F3 of ~80 hz to pair with an existing Polk Audio 8” sub that I have had for many years
• Using a silk dome tweeter (personal preference)
• A tweeter with a low Fs so that I could use a low crossover frequency. After readings Scott’s excellent design summary (http://goo.gl/XboqRW), I learned that this would improve the integration of the drivers and the soundstage.

Driver Selection:
Dayton Audio RS150P-8 6” woofer (295-363)

Dayton Audio RS28F-4 1-1/8” (275-140) silk dome tweeter.

Enclosure Design:
As I learned the hard way, during this process, just because you buy a pre-fabricated enclosure does not mean that no tools or woodworking skills are needed. Doing the driver cut-outs in the front baffle proved to be quite a challenge for me. Even though I made a couple of practice runs on some scrap wood, my cut-outs and countersinks were still far from perfect. Being a perfectionist this bothered me, however since the Dayton enclosures are supplied with grill covers, I will be the only one who ever knows how ugly things are underneath. If I ever build another set of speakers, I will invest in a proper plunge router, a Jasper jig and will spend more time building templates/guides.

Enclosure Assembly:
I added mass to the woofer, following the procedure outlined by Scott. I lined all interior surfaces of the enclosure with Sonic Barrier 1/2″ Acoustic Sound Damping Foam (260-520). Following this, I calculated the remaining internal volume of the enclosures which started at 8L. After subtracting the volume for all internal components, I was still sitting at about 6L. Once again, probably due to my inexperience, I spent a lot of time worrying about the final Qtc of my design. I ran calculations in Unibox and Bagby’s Woofer Box. This proved a frustrating experience as results were all over the map depending on what leakage and absorption factors were chosen. I was ok ending up with a little lower Qtc than Scott’s ~0.8 since I knew I would be pairing my speakers with a sub from the start. After much deliberation, I finally decided to reduce the volume by ~1 more liter using non-hardening modeling clay. The resulting internal volu me of slightly less than 5L produced a Qtc of right around 0.7, based on my best guess for leakage and absorption factors. I also loosely filled the enclosures with Acousta-Stuff (260-317).

My last area of struggle was worrying about diffraction off the wooden frame of the grills supplied with the Dayton enclosures. Scott had used some leftover damping foam around the tweeter in his design. He also lined his grill backer board with foam. I ended up blending both concepts and covered the face of the baffle with foam. The result, from a visual standpoint, was absolutely hideous. However, once again, the grill covers came to the rescue.

Crossover Design:
Being an engineer and just naturally curious, I was uneasy just blindly trusting Scott’s crossover design. I attempted to duplicate his modeling using Jeff Bagby’s free Passive Crossover Designer. This was unsuccessful since his spreadsheet, while excellent, does not quite have the flexibility to model a design this complex (or at least I could not figure out how to). I was successful, I thought, in building a duplicate model in XSim. However, for the life of me, I could not duplicate Scott’s calculated acoustic and electrical crossover points. I am sure the error was on my part and was related to driver acoustic center offset. I finally gave up and, in the end, trusted Scott’s experience.

I was surprised at the difficulty of assembling the crossovers. Being my first build, my soldering skills were embarrassingly poor. I ended up working on these for months since I was only able to spare a couple of hours a week. I have no way to test the assembled crossovers or speakers, for that matter, so I really have no way to no if I built them correctly. Once the crossovers were assembled, I had to figure out how to mount them in the enclosures. The stiffening brace in the middle of the Dayton enclosures, made this a challenge. The woofer’s crossover was fairly heavy and I did not want to rely on hot glue alone. The angle for screwing the crossovers to the side walls was just too tight. I ended up screwing them to the lip in the front, supplemented with hot glue to the sidewalls.

Conclusion:
After more than six months or research and off/on work, I finally finished the speakers and connected them into my existing system. They are driven by a Yamaha RXV377 home theater receiver that delivers about 85W per channel. My listening area is small, but I am not using these speakers in a true near field set-up as Scott recommended. My set-up is an 8 foot equilateral triangle with the tweeters being at ear level. Fortunately, my receiver has a Straight mode that supposedly by-passes as many internal components as possible to minimize interference and distortion. I listen in this mode, with the sub’s crossover set at 80hz and the level just adjusted by ear.

Being my first speaker build, I was not sure what to expect. I have been into car audio for 25 years or so and have an embarrassingly expensive aftermarket system in my car. However, my exposure to truly high end home audio components is very limited. All I can say is “wow”. My wildest expectations were exceeded. These little speakers emit a wall of sound that appears to be about 12 feet wide and 6-8 feet tall. The sweet spot is fairly wide and forgiving. Two people can sit comfortably on a couch and the soundstage and imaging are outstanding for both. The integration with the subwoofer sounds nearly perfect to my ears. I have not run the receiver’s parametric analysis and I am not sure I ever will. I am beyond happy with what I hear now.

The only downside is that these speakers are going to require me to change my listening habits. No more streaming from my phone to a little Bluetooth receiver that I have connected to the Yamaha. No more compilation CD’s full of 128 kbs MP3’s. The sound, as compared to playing an audio CD in the system’s Blu-Ray player, is just unacceptable. CD quality sound, however, just blows me away. The accuracy of instrument sound reproduction, the ability to hear the performers breathing, the feeling of being “present” at a live performance are amazing. Looks like I will be re-ripping all my CD’s to FLAC’s and listening via USB from now on.

I want to thank Scott Hinson for his generosity in publishing such a detailed write-up of his design process for the DIYRM-A. Without this document I could never have dreamed of taking on a project like this. I am very glad I did and am sure I will enjoy these speakers for many, many years to come.

About the Designer:
Long time car audio enthusiast. Long time home theater enthusiast. First time to DIY a pair of speakers and first time to experience “high end” home audio, stereo sound.

Designer:
Craig

Project Category:
Amplifiers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
the Footnote 5 watt guitar combo amplifier for $30 bucks

Design Goals:
I wanted it to look like an amp and be practical and traditional.

Driver Selection:
its a 6.5″ Eminence guitar speaker 299402

Enclosure Design:
Had to design the cabinet myself, but not that big of a deal, even for a first timer. I went with a traditional look. I routed the side panels and that is what holds it together, didn’t need screws. I also wanted it to look already broke in.

Enclosure Assembly:
7/16 particle board for most, the 2 side panels are pine boards
The front panel is at a 70 degree angle

Conclusion:
An old man that had never built a speaker or amp, or even assembled one, pulled it off in a day without instructions

About the Designer:
In my 50’s, never tried anything like this, but was confident I could do it. I plan to donate the amp to a kid who wants one for Christmas and may not receive it another way.

Project Parts List:

Designer:
CDC

Project Category:
Subwoofers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Just a cheap system for the minivan.

Design Goals:
A lot of bass at a low cost.

Driver Selection:
4 Titan 15″ woofers. Part # 299-1056

Enclosure Design:
Ported box

Enclosure Assembly:
MDF, drywall screws, fiberglass resin

Crossover Design:
Built into amp.

Tips & Tricks:
This is by far the cheapest set up I have done and the outcome is great!

Conclusion:
Really surpasses my expectations.

About the Designer:
I have built and installed numerous car audio/video systems. I have owned several custom cars. I enjoy working with computers and electronics.

Designer:
Shannon Ley

Project Category:
Headphones/Accessories

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
Under $100

Project Description:
A while ago I was wondering whether it was possible to make a great sounding pair of 3D printed headphones using readily available off the shelf drivers. There weren’t many people who had done so on the internet, and there were few resources available on how to make headphones sound great, so it ended up being an awesome project!

Using Dayton Audio CE38MB-32 drivers, my first pair were a very simple open back design, built to validate whether or not headphones were ‘do-able’. They sounded great, but once I built a closed back design, things didn’t sound so good! I then built a frequency response test rig (see photos) and explored the effect of all the design variables. All my findings can be found at www.homebrewheadphones.com

The test rig uses a flat plate rather than human ear shape (that will be on the next version!), so is somewhat limited in its findings, but was extremely handy nevertheless.

The final headphone design incorporates all the findings from my testing. It also includes a 3D printed adjustable headband and removable cables.

The parts for a build cost around $35 in total.

Design Goals:
I wanted a design for which as many of the parts as possible could be 3D printed, and the ones that couldn’t (eg drivers, cushions etc) to be cheap and readily available. Needless to say, the sound had to be great too.

Driver Selection:
Daytion Audio CE38MB-32 – they are cheap, readily available and sound good.

Enclosure Design:
My testing showed that volume of the enclosure didn’t have as much impact on the frequency response as some other variables, so there was little science behind the enclosure design – they were mainly designed around aesthetics and packaging of all the components. I did try to minimise the volume somewhat, as the low end frequency response needed attenuation to flatten the frequency response curve.

Tips & Tricks:
In a closed back housing, the Dayton Audio CE38MB-32 drivers give way too much bass relative to the treble. I found that blocking all but one of the holes on the back of the drivers reduced their low end frequency response, making the overall frequency response curve much flatter.

Spot gluing the drivers in (rather than gluing around the entire perimeter) also helped flatten the frequency response curve.

Conclusion:
It took a lot of work and testing (to understand how the design variables affect the sound), but I am very happy with the result, both in terms of how they sound and look.

About the Designer:
Former automotive engineer and tinkerer, now entrepreneur and tinkerer.

Parts Used:
Dayton Audio CE38MB-32 drivers part # 285-131

Bose QuietComfort QC15 QC2 replacement ear cushions

Sol Republic Master Tracks HD V8 V10 V12 X3 replacement cable

2 x 2.5mm audio jacks

4 piecies of approx 10cm (2″) long hookup wire with ends stripped

Loctite Gel Super Glue

Plasticine

Designer:
Kerry Armes

Project Category:
Tower Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
The Standards are a high performance to dollar floor standing speaker. The name comes from two things. First, I wanted to do a finish on these cabs like my favorite guitars, Gibson Les Paul Standards. Second, these are going to be my new reference speaker (until I build something better!).

Design Goals:
I wanted to create a budget oriented, full-range tower with high-end sound. My goal was to keep parts close to $300 before cabinets. Parts-Express knock-down cabinets would be used for my design, but you can always build a cabinet using the same dimensions on your own.

Driver Selection:
I’ve long eyed the Peerless HDS Exclusive woofers from Parts-Express. They have some additional copper in the motor over the standard HDS line that lowers midrange distortion even further. The silver frame and phase plug make them fairly attractive and they provide a lot of performance without being too crazy on the price. For tweeters, I chose to go with a long time favorite, RS28A. There are no other tweeters that PE carries around that price point that can beat it. I chose the aluminum model over the silk dome RS28F because I personally prefer the sound of metal tweeters.

Enclosure Design:
The enclosure is the Parts Express 1.16 cu ft knockdown cabinet. Both drivers were centered horizontally on the baffle with the tweeter located 3” down from the top edge and the woofer 9-5/16” down from the top edge. I used a 3” diameter port that was roughly 9.5” long to tune the enclosure to around 38 Hz. I used a PVC elbow for my port and recessed it about ¼” into the back cabinet. After measuring the impedance, I didn’t need to add any additional length to the elbow I bought to reach my tuning frequency. You can get away with a shorter port if you go with a 2.5” diameter port, but the hardware stores around here didn’t carry 2.5” PVC. If you go with a 2” port, you run the risk of running into some port noise. You might be ok if you go with the 2” Precision Port from Parts-Express, but you will need to calculate your own lengths if you change the port diameter.

Enclosure Assembly:
Using the CNC cut cabinets makes for fairly quick assembly in most cases. My only minor snags were 1) not having enough clamps, which led to a few edges that needed to be filled with wood filler or sanded before veneering, and 2) I had to cut one of the braces to make room for the port. I used the cut pieces in place around the brace to add keep some of the support on the lower end of the cabinet.
I lined the cabinet with two layers of roofing asphalt, 2) I had to cut one of the braces to make room for the port. I used the cut pieces in place around the brace to add keep some of the support on the lower end of the cabinet.
I lined the cabinet with two layers of flashing tape (a roofing material you can pick up at a hardware store) for some damping to the cabinet walls and then covered that with a layer of denim insulation around the driver and leftover eggcrate foam I had lying around the port. I also added a layer of the denim insulation on the bottom of the cabinet over the crossover. You want to make sure you don’t pack too much in the cabinet, as it will lower the port output too much and affect the bass.
After the cabinets were together, I filled any seems and veneered the cabinet using Heat Lock glue and the iron on method. I used figured maple veneer and finished it with Trans Tint black dye and water based polyurethane. I decided to try something interesting for the base for these, but it didn’t work out as well as I had hoped. I bought some aluminum sign standoffs and aluminum bar stock on eBay and decided I was going to make my own outriggers. The bar stock I cut using a jig saw with a metal blade, but I couldn’t get my cuts as straight as I wanted with the jigsaw so I’m not completely happy with the results. I also had an issue where my drill bit must have slid some and didn’t notice, so one of my holes didn’t like up where I wanted it to for the standoffs. The aluminum is much easier to do this on than wood, so be careful if you are using a standard drill and not a drill press.

Crossover Design:
I designed the crossover using measurements from Dayton Audio’s DATS and Omnimic software/hardware packages and Jeff Bagby’s Passive Crossover Designer Excel spreadsheet. The crossover was a fairly straight forward damped 2nd order electrical/acoustical on the woofer and 3rd order electrical/acoustical on the tweeter. I used all poly caps in this one to make sure I didn’t have any degradation of the sound from NPE caps on these drivers. My RS28A tweeters measured lower than specified sensitivity, so I only used 2.4 Ohms of padding. I would highly suggest if you build this to buy a few more resistors in .5 or 1 ohm increments up to 5 ohms or so for the tweeter and add resistance to your personal preference. If you end up with a normal sensitivity level, you’ll want more resistance or your speakers will sound bright.

Tips & Tricks:
Using the premade cabinets makes things fairly straightforward on cabinet construction. Just make sure to take your time and get everything lined up as best as possible. Finishing, I learned a few lessons. Using the black dye on the maple, there were a few spots where the glue had seeped through in the productions process on the seams of the veneer as it came, not ones that I cut. This led to a few spots that wouldn’t take the dye. I had to go back and touch these up with a black permanent marker before finishing. I also tried to wrap one continuous piece of veneer around the face and two sides of the cabinet. I wouldn’t try doing this again without using veneer softener. I had a couple problems doing it without, which led to some slight cracking and some bubbling of the veneer in a couple spots close to the round overs.

Conclusion:
Even though I was using a knockdown cabinet, I wanted to stretch myself a bit on it and try some new techniques. Using dye and working with aluminum were both things I was trying for the first time. Overall, it worked out OK, but could have been better finish wise. Sound wise, these are everything I was hoping for. The bass on these drivers is pretty impressive for being only a 6.5” woofer and would be satisfying for most people without a sub. Everything is very clean and the low distortion drivers really let all the subtle details of the music shine through. They image well, and they have much better dynamics than I expected out of 6.5” 2-way design.

About the Designer:
Kerry recently separated from the U.S. Navy after serving 8 years as a nuclear submarine officer. In his time with the Navy, he picked up a significant amount of experience in acoustic and electrical theory. Today, he works as a Project Manager in Ann Arbor, MI. Kerry has been a long time speaker and DIY addict, beginning with car audio in the ’90s. While other kids were trying to get the most “boom” from their cars, Kerry was installing and tweaking his system for maximum sound quality. Kerry got into DIY crossover design in 2012. Since then, he has designed and built around 2 dozen speakers. Kerry focuses on using high quality, low distortion drivers with wide overlap to get the best sound while minimizing the complexity of a crossover. He looks for unique drivers that offer specific benefits for a chosen design to use in a way that maximizes the positive traits and minimizes the negatives. Kerry recently started a website with instru ctional videos to help other DIY builders learn the basics of crossover design and speaker measurement techniques.

Project Parts List:

Designer:
mzisserson

Project Category:
Tower Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
The Tenacious 3 is a budget loudspeaker with not-so-budget sound, that anyone can build with a few simple tools, aimed to maximize performance in a small foot-print. Utilizing the Denovo “Knock-down” 1.16 cubic-foot cabinet, the T3 fits where any stand-mounted loudspeaker will yet allows for the performance of a 3-way, tower loudspeaker.

Design Goals:
When I found out I was going to be part of the Parts Express Design Team, my first thought was how to give back to not only to the DIY loudspeaker community and Parts Express, but also to the newcomers who are looking to enter the hobby.

The Tenacious 3 (T3) had to be easy to build, offer very high performance for the dollar, and set an example of what is possible in the DIY world when one applies a little tenacity. Many times, newcomers on a tight budget are limited to modest, 2-way, stand-mount loudspeakers. The T3 had to offer a different option. A small-footprint tower loudspeaker that would fit just about anywhere a stand-mounted bookshelf loudspeaker would clearly was the glaring resolution. It also must be a simple to build as possible. Luckily, Parts Express carries an easy to build pre-cut cabinet to get the design going.

Taking advantage of a tower loudspeaker was paramount in this design and not simply building a bookshelf loudspeaker in a big box. This meant having high quality, strong bass response. To achieve this, the T3 needed to utilize a large, or multiple small woofers to increase power handling and sensitivity. Having the extra cabinet space also allows for a sub-enclosure which is required by most dedicated midrange drivers.

The T3s also had to capitalize on the advantages of a 3-way loudspeaker. Some of the largest advantages include, but are not limited to, using the drivers well within their wide radiating patterns, lowering distortion by taking the midrange out of the woofers, using a small-format or non-dome type tweeter, and removing the worry about having a woofer (or woofers) that have a smooth top end.

Finally, they had to be easy to build and finish. Typically a 3-way tower loudspeaker can be intimidating due to complexities like treating cabinet resonance, building a sub-enclosure for the midrange, handling large panels though the building process, and even finishing the large enclosure or crossover. The T3 addresses all of these concerns with simple, yet effective solutions.

Driver Selection:
The Tenacious 3 is anchored by a pair Dayton Audio DA-135 5.25” woofers. High value and good looks were part of the criteria since and to make the build easy, counter-sinking was not an option. Alone, a driver that does not have to be countersunk in order to look good AND performs well narrowed the field of what can be used.

While the DA line is well-respected, yet the DA-135 does not get much love. Its larger sibling is a strong woofer, and it’s smaller sibling a great mid-woofer. This middle-child offers strong bass performance, especially in pairs, though it does not extend as deep as its big brother. Conversely, the DA-135 possesses decent top-band performance, but not as good as its little brother. Yet the awkward middle child fit the bill perfectly for the T3 based on its physical size, and the ability to play to a solid 40Hz in-room when used in pairs. Further, top-end response was not a concern since the midrange will be taking over before it becomes a concern for the DA135s. All factors combined, the DA-135 is used in the T3 within a range that allows it to perform as ideal as possible; which is a great advantage of a 3-way loudspeaker when selecting budget drivers.

The midrange will be covered by a lil’ gem: The Visaton FRS5X. The FRS5X has good sensitivity, simply requires a 2” hole for mounting, and like the original FRS5 has an extended, flat response with vanishingly low distortion. Using a small midrange makes enclosure tuning a breeze and simplifies the sub-enclosure requirement which keeps the build difficulty low.

The top octaves will be covered by the Dayton Audio ND16FA 5/8” tweeter. This tweeter was selected for its simple mounting requirement, extremely wide dispersion, smooth response, and low distortion. The ND16 is a proven performer and has found its way into the DIY world countless designs. Standing on the shoulders of the FRS5X, the ND16 will be crossed over fairly high which will help leverage its greatest strengths.

Enclosure Design:
The cabinet for the Tenacious 3 is the Denovo 1.16 cubic-foot “knock-down” tower loudspeaker enclosure kit from Parts Express. This well machined and braced enclosure that is made from 0.75 inch medium density fiberboard (MDF) arrives as a flat-packed unit that assembles easily and fits together snug. A definite win.

From there it is up to the designer to use its space and form to make it a loudspeaker. In the case of the T3s, I chose a vented alignment which is tuned to 34Hz using a two inch diameter, by five inch in length port. This port is available from Parts Express so no tricky PVC port work is required. The port is bottom-mounted which I prefer for several reasons including coupling with the floor and diffusion of any midrange or port resonance that may find its way through the tube inside the cabinet.

Inside the cabinet is lined on three sides in strategic locations with Sonic Barrier and stuffed with and total of two-thirds of a pound of Acousta-stuf. The cabinet stands tall on spikes as well to give some breathing room. All is not lost if you have high-pile carpet and are worried about blocking the port: Any local home improvement store has odd ceramic tiles lying around. Just grab a pair to put under the speakers and you are ready to roll.

The bass tuning was chosen to maximize transient response while preserving as much depth as possible. I have found this tuning to exist somewhere a hair under maximally flat for the DA-135, but not so deep it starts to create more problems than it solves. The overarching goal: As much symmetry as possible through the entire range of the loudspeaker starting from the bottom-up.

A creative and simple solution needed to be had for the mid-range enclosure. Toying with many ideas, the one that stuck was a 22.5 degree “Street” PVC elbow with a PVC cap at the non-flared end. This provides an un-even enclosure which disallows standing waves to form. I also dampened the inside with HVAC perma-gum dampening which acts both as a sealant and a non-hardening dampening material. Parts Express “Calk Gasket” material is the same stuff and works just as well. A small fist-full of Acousta-Stuf rounds off the mid-enclosure.

The position of the drivers including the offset off the midrange and tweeter helps to idealize the diffraction signature and crossover points. A large part of the design was to eliminate the need for a router or milling of any sorts. Easy tools are all that is required. After drawing the driver positions directly onto the enclosure using a ruler and compass, a drill with an inexpensive Forstner bit set took care of the midrange and tweeter holes, and a jigsaw the woofer and port holes.

Chamfering or rounding-over the back-side of the midrange and woofer holes is usually a must when building a loudspeaker. Since a router could not be used, I grabbed a rasp, roughed-out rounds on the back-side of the midrange and woofer holes then sanded them smooth. As stated so eloquently by one of the most ingenious and resourceful people I know, despite the fact he never graduated high-school, “If it looks stupid and it works, it ain’t stupid”! Talk about tenacity…

Enclosure Assembly:
Parts Express provides a wonderfully detailed drawing via Sketchup for assembling the Denovo 1.16 cubic-foot flat-pack enclosure so there will not be much focus on that detail. With only the rear CNC machined, some care is needed to make sure all aligns well, however it is small-beans to deal with in comparison to building an enclosure of this quality from the ground-up.

All of the placement of the drivers on the baffle were optimized ahead of time then drawn with a compass, a square, and a ruler right on the baffle itself

Once the holes were cut/drilled in the baffle, a round-over was put on the rear of the woofer cutouts and midrange cutout as described above. At this point, the baffle is still not attached to the enclosure. This is also the time the bottom of the enclosure received it’s hole for the port, and four, one-half inch holes for the floor spike keepers. Like the baffle, all positions were drawn right on the bottoms before cutting/drilling.

The midrange enclosure, as mentioned, is a PVC 22.5 degree elbow which is flared at one end. This is long enough to provide the required breathing space for the FRS5X and wide enough to afford room for the cut-out through plus the round-over on the rear of the front baffle for the midrange.

For assembly: First, use some expanding polyurethane glue to secure the flared end in place over the midrange cutout. It is heavy enough not to “float” as the glue expands. Once dry, I drilled a hole for the wiring to pass through, pressed in some rope-calk to dampen the hard, plastic “tink”. Some PVC glue took care of securing the cap to the end of the elbow and that is all there is to the midrange enclosure save a small fist-full of Acousta-stuf during final assembly.

Despite the quality of the Denovo 1.16 cubic-foot cabinet, I noticed the sides were a hair proud. Nothing to really worry about but good enough to easily catch your finger nail when running perpendicular to it along the seams between the braces, top, and bottom. For good measure, the expanding glue was used to attach the baffle to assure no air-leaks or vibration points.

The final trick-shot is mounting the FRS5X. A 2” hole is all that is required to mount this from the front, though rear-mounting seems to be what it was designed for. Using the rope-calk, I ran a bead around the edge of the driver’s frame and after feeding the wiring through the midrange enclosure gently pressed it in place. A low torque setting on the drill/driver combined with a slow speed evenly seats it. There will be squeeze-out from the gasket confirming a very good seal that is easily trimmed away with a precision model knife… (wait, that’s a fancy tool. I promised none of them)I mean a razor knife.

Knock in the ND16 *carefully*, mount/hook up the crossover internally through the DA135 cutouts, split 1/3lb. of Acousta-stuf between the bottom of each cabinet around the port (not restricting the port in any way) and the top of the cabinet above the midrange enclosure, attach some speaker wire and hit play!

Crossover Design:
If all of the loose ends and details are tied up during the initial design phase of a speaker, designing the crossover is fairly straight forward. Aside from the filter networks, I am not a huge fan of using contour, notch, and compensation circuits unless planned ahead of time since crossovers only reduce, not add. Unless we are talking in terms cost, then they add! My hand got forced into using a Zobel network, a type of filter that flattens the impedance after the driver resonance due to inductive rise, on the midrange. Otherwise the crossovers for the T3’s are very straight forward with the approximate crossover points being 450Hz and 4000Hz.

The T3 is a 4 ohm nominal speaker. The minima is 3.48ohms at 128Hz, nearly resistive, making my “8 ohm only” fifteen year old pioneer home theater receiver perfectly content while driving them with movies and music alike. The rest of the range it is a safe load too, which remains easy enough for just about anything to drive.

All filters were targeted as 2nd order Linkwitz-Riley. It is generally accepted that “2LR” type filters are a nice balance of performance vs. complexity. The Zobel network adds a small capacitor and resistor to the tail of the midrange. There is a resistor in front of the midrange and tweeter to help level-match those drivers to the woofers once the baffle step was accounted for. Since the T3 is a 3-way loudspeaker, the crossover has about five more components than a typical 2-way loudspeaker. It is not necessarily more complex, just a little bigger and since this design is about a little tenacity going a long way, I say bring it on!

Tips & Tricks:
Here are some things that will make the build-life easier.

Mount the binding posts before securing the port, unless you have a fourth joint in your arms, even then it will be sketchy.

Gently solder a long length (48” or so) of wire to the ND 16s then throw them into freezer for about ½ hour before knocking them in. This will not hurt the tweeter and make the already tight fit seem a little less hairy when smashing the tweeter with a beating device.

If there is any place there may be a hankering to upgrade, it should be the 47uF capacitor in the midrange. To keep it budget friendly I put in the $2 cap, not the Auydn $12 cap.

Take your time! It is the one free thing we get as a DIY-er. Any loudspeaker you build can potentially last decades, make it worthwhile even if it is just a stepping-stone to a larger, more complex build.

Lastly, weather screws, binding post hardware, or the inserts for the spiked feet it is not necessary to tighten more than firm hand-tight plus ¼ turn. A rule of thumb I have developed over many-a-year of ruining many-a-thing.

Conclusion:
The Tenacious 3 turned out to be a budget loudspeaker with a not-so-budget sound. Hitting the design goals always brings a sense of real accomplishment.

Challenging myself to capitalize on all of the advantages of a small footprint floor-standing loudspeaker that can offer an different option to a modest stand mount 2-way, a 3-way loudspeaker with the least build complexity as possible, all while keeping it all budget conscience was a lot of fun. There is a certain gratification to watching people’s hair stand on end when they are moved by a hand-full of entry-level drivers that is unique to a tenacious budget build. I am thankful to Parts Express for inspiring me to dig deep and stretch my knowledge.

About the Designer:
Michael Zisserson started tinkering with speakers at 13 years old and by 18 he was building replicas of famous loudspeakers. During this time, he grew his audio knowledge working for a local Hi-Fi audio store. In 2004, Michael graduated from New England Tech. with a degree in Electronics Engineering Technology while managing a retail audio/video store called Cambridge Soundworks. Through the years, Michael kept studying loudspeaker design, became a reviewer for Stereomojo online and continues to design and build loudspeakers whenever he is not adventuring with his family. Speaker building and listening to music with local audio enthusiasts occupy most of Michael’s leisure time, but as filler he also enjoys hiking/geocaching, survival training/camping, reading, and home improvement.

Parts Used:
295-330    DA 135 5.25″ Dayton Woofer    4     $21.54
292-640    FRS 5X-8 2″ Visaton full range    2    $11.08
275-025    ND16FA-6 Dayton Tweeter    2   $9.64
300-7066    Denovo 1.16CF cabinet    2    $65.74
260-387    2″ Adjustable Port Tube    2    $3.18
091-1250    Black/Gold binding post    2 pair 1    $14.49
240-730    1/2″ super cabinet spikes    2    $5.60
260-520    1/2″ Sonic Barrier    2    $9.97
260-317    Acousta-Stuf 1lb    1   $11.50
260-400    12″ speaker caulk 72pcs.    1    $9.50
266-556    2.5mH Inductor    2    $9.79
266-552    1.5mH Inductor    2    $7.98
266-806    0.2mH Inductor    2    $4.85
255-232    0.56 mH Inductor    2    $8.03
027-358    80uF NPE cap    2    $1.98
027-352    47uF NPE cap    2    $1.45
027-111    2.7uF Cap    2    $2.18
027-110    2.2uF Cap    2    $2.04
027-112    3.3uF cap    2    $2.25
004-10    LI 10R0 Resistor    2    $1.38
004-2.4    LI 2R4 Resistor    2    $1.38
004-1   R5 LI 1R5 Resistor    2    $1.38
Other Some wire, a few screws,ect…    1    $50.00

Designer:
Phil

Project Category:
Subwoofers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
Over $1,000

Project Description:
Our church was outfitting a new space with a 21″ platform height. Commercially available low profile installation subwoofers command a hefty premium to less architecturally friendly models, so we decided to fabricate enclosures for the space.

Design Goals:
We wanted to utilize an enclosure well under 21″ high that would not attract attention in the space in a black finish. Extension below 40Hz was desirable, but not mandatory.

Driver Selection:
The Dayton Audio RSS315HO-4 (295-466) driver was chosen. With high Bl, low Cms, and three shorting rings, this driver is built more like a typical professional audio woofer.

Enclosure Design:
The enclosure is a conventional vented box with slotted port tuned to 31 Hz. Woofer fires down from a small recessed location.

The enclosure is designed to have a slight peak at Fb to facilitate use of a second order Butterworth HP filter above Fb, giving an overall flat aggregate response.

Enclosure Assembly:
Enclosure flats were CNCed out of 18mm, 13 ply baltic birch plywood. Enclosures were assembled using Titebond III wood glue and 18ga brads.

Drivers and handles are affixed via #10 flanged barbed inserts. Neutrik NL4 inputs are retained using #6 t-nuts.

Crossover Design:
Loudspeaker is processed using church system DSP. Baseline filter is 2nd order Butterworth HP at 33Hz. Final filter parameters to follow after we complete ground measurements on the finished units.

Conclusion:
We assembled five enclosures on Saturday evening, and deployed the unfinished units for the first Sunday AM service in the new space.

About the Designer:
Phillip Graham moonlights in professional audio and has been building speakers off and on since the mid 1990s. From October 2011 to October 2016 he wrote the technical column for Front of House, a leading professional audio trade magazine.

Products Used:

Project BOM, DXFs for cabinet shop, PDFs of CAD, all Solidworks files, and build photos may all be found at the following Google Drive link. Measurements to follow in the coming weeks:

https://drive.google.com/drive/folders/0BwZr3b_1ro5UTjUxYXFBU3FTUzQ?usp=sharing

Designer:
Banger Speakerz

Project Category:
Tower Speakers

Project Level:
Beginner

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
Always wanted to build a nice set of tower speakers so this is what I ended up doing. 69.5″ tall hand made speaker enclosures with 2 subs in the rear, 6 woofers and 2 mids and 1 ribbon tweeter in each tower.

Design Goals:
My design goal were more of an elegant look for the most part but I also wanted some sound quality too.

Driver Selection:
6 HiVi M6N woofers, 2 HiVi M3N midrange and 1Beston ribbon tweeter
2 TangBand 6.5 subs in the rear of each cabinet along with a Dayton Audio 100w plate amp

Enclosure Design:
Slim design at 69.5″ tall 8.5″ wide and 8.5″ deep.

Enclosure Assembly:
Enclosure is all made out of 3/4″ Mdf wood. Front face place and base stand painted to a high gloss black finish and a fir wood veneer around the enclosure stained with Red Sedona finish

Crossover Design:
Custom 3-way crossover

3-Way Crossover Network

Low-Pass (LP) Filter:

1 required

Type:

2nd-Order All-Pass (APC)

Desired Corner Frequency:

Band-Pass (BP) Filter:

450 Hz

1 required

Type:

2nd-Order All-Pass (APC)

Desired Lower Corner Freq:

450 Hz

Desired Upper Corner Freq:

4500 Hz

High-Pass (HP) Filter:

1 required

Type:

2nd-Order All-Pass (APC)

Desired Corner Frequency:

4500 Hz

C1 =

3 μF

, Polypropylene, 0.00764 ohms

C2 =

68 μF,

Polypropylene, 0.00192 ohms

C3 =

5.1 μF

, Polypropylene, 0.00697 ohms

C4 =

33 μF,

Polypropylene, 0.00269 ohms

L1 =

0.25 mH

, Air Core (#16), 0.302 ohms

L2 =

2.5 mH

, Air Core (#16), 0.538 ohms

L3 =

0.2 mH

, Air Core (#16), 0.273 ohms

L4 =

3 mH

, Air Core (#16), 0.595 ohms

Band-pass Gain = 2.08 dB

Conclusion:
Very happy with my outcome in the major project. The clarity is right where I’d hoped it’d be. Crystal clear to my ears

About the Designer:
Always wanted to tackle a wood working project and something like this has been in the works for a long time. I’m an aerostructures painter so I stay busy with working lots of overtime and trying to spend as much time as I can with my family so this project took me many late nights and weekends to complete. I’m thankful for all the advice I was giving for any questions I had about this project and for my family and friends that had to listen to countless hours of how excited I was during the whole project. I’m by no means a carpenter but I think I’ve learned a few new skills along the way and look forward to making many more projects like this one!

Project Parts List:

Designer:
Daniel Tonks

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
I currently own a set of large, floorstanding speakers as well as a moderately sized pair of bookshelf speakers, but I wanted a set better suited to near-field listening for a computer desk. I specified a level of “Intermediate” simply because the cabinets aren’t pre-fab. These are certainly easy enough to build if you know how to use a table saw, sand paper and spray paint.

Design Goals:
Quick, cheap and simple! Obviously I wanted them to sound good as well, but for me that went without saying. Lastly, I wanted to build a pair of speakers that didn’t just look like drivers in a box.

Driver Selection:
These were meant to be easy on the wallet. Because of this I didn’t want a driver that would necessitate the use of filter networks and compensation circuits. I ended up choosing the Dayton Audio DS90-8 for the task.

Enclosure Design:
I did some calculations by hand and utilized WinISD and WinSpeakerz for further simulations. I settled on a volume of ~0.08 cubic feet with a port 4 inches long by 1 inch diameter. I suspected that having chamfered corners would help reduce the effects of baffle diffraction (compared to the usual rectangle), but without building a second set for comparison I guess I won’t actually know if there’s an audible difference.

Enclosure Assembly:
With a rough idea of what I wanted them to look like I headed to the woodshop and got started. I actually built two pairs in parallel: one set for myself (the test pair) and one as a gift. I began by simply constructing rectangular enclosures, then raising and tilting the tablesaw blade to make the angled cuts.
I sanded the bare enclosures up to 220 grit, then sprayed them with high-build primer, wet-sanded that up to 800 grit and then painted them white. I chose to skip clear coating them and just used a high gloss enamel paint instead.

Crossover Design:
No crossovers here!

Conclusion:
I was blown away. Overall I’m very happy with how these sound. I tested them with a small Emotiva amplifier and high resolution digital files. Test tracks included Nils Lofgren’s “Keith Don’t Go”, Sarah McLachlan’s “Angel”, the MTV Unplugged recording of Alice in Chains’ “The Rooster”, Earth Wind & Fire’s “Sing a Song”, the main theme from Schindler’s List, Rachmaninoff’s “Rhapsody on a Theme by Paganini, Op. 43″ and a few others.

Some strengths: Great imaging and detail, instruments (guitar and piano in particular) sound very natural.
Some cons: I’ve found that vocals can sound a little bright for my taste.

I took some very informal measurements in-room with an un-calibrated mic, so I won’t place too much stock in the results, but measurements on axis at ~1m show an f3 around ~65-70Hz.

About the Designer:
I’m an electrical engineering student with too many interests for my own good.

Project Parts List

Designer:
Lee Teeples

Project Category:
Freestyle Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
The satellites were design in Solidworks using the 737-900s that Southwest Airlines use as reference. The model was spit into sections that could be 3D printed. After that, a lot of sanding, primering and painting finished them out. All electronics are mounted in the sub cabinet.

Design Goals:
My wife I a proud member of the Southwest Airlines family and to celebrate, I designed and built these so she can show her spirit at the office. They were intended for her desktop audio but the system works great as a bookshelf system being fed by a mobile device or a Sonos Connect.

Driver Selection:
Dayton Audio ND65-8 2 1/2″ Full-Range Driver
Tang Band W5-1138SMF 5 1/4″ Subwoofer

Enclosure Design:
Satellites- sealed pods
Subwoofer- ported .3 cubic feet tuned to 44 hz

Enclosure Assembly:
Satellites- 3D printed and finished
Subwoofer- Birch

Crossover Design:
Built in electronic

Conclusion:
Really like how it turned out. Sounds great! My wife is estatic.

About the Designer:
Car audio installer/fabricator for 20 years. Now work in the New product development of a manufacture.

Designer:
Mark Rivera

Project Category:
Portable Speakers

Project Level:
Advanced

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
This is an aluminum fabricated sheet metal enclosured Bluetooth boombox using Dayton ND-91 drivers and the Dayton 50w Bluetooth boards and accessories.

Design Goals:
Goal was to design a good sounding, medium sized boombox around one of my favorite speakers and the newly available Dayton boards with BT circuitry built in. This one uses 2 of the battery boards available with three 18650’s each.

Enclosure Design:
Aluminum formed, welded and shaped construction, stainless steel back cover

Crossover Design:
Full range

Conclusion:
This is a nice sounding unit that plays for 4-8 hours depending on use, and will work really well for camping or whatever portable sound solution is necessary. The lower voltage supply of the lithium batteries and the low sensitivity of the drivers don’t make it the loudest box available, but it hits nice and low, has very smooth midrange, and the highs are adequate if you stay mostly in front of it or a decent distance away. Overall satisfied, but dreaming bigger and louder…

About the Designer:
I’m a tinkerer whose designed and built several systems for personal use, from home theater to car audio to portable… I work in metals daily and have been exploring more nontraditional enclosures for some time, with decent success…

Project Parts List

Designer:
Footnote amp

Project Category:
Guitar and Bass Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
Full CNC FootNote amp build.

Design Goals:
To get my daughter to get her hands dirty.

Parts Used:
249-400 – Build Your Own FootNote Guitar Combo Amp – Components Only

Conclusion:
I used this kit to get my daughter envolved with some basic woodworking. This is the front face plate of the enclosure, we will leave the rest up to you guys since it’s prettt simple.

About the Designer:
Just a DIY guitar amp made with my daughter. Front face plate was done with a home built CNC machine.

Designer:
bhearts

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
i have never dealt with open baffle designs before, but i love how this turned out. wonderful, flat bass response that plays alot lower frequencies that i ever would have expected from an open baffle design.

Design Goals:
make a great sounding tower that i can give to my in laws while making them think i spent tons of money building them something that also looks good.

Driver Selection:
6.5 inch poly cone midbass speakers that are on the factory buyout deal because who doesnt want to make awesome towers using 4 dollar speakers and the goldwood 1″ softdome horn tweeters

Enclosure Design:
the face of the OB is 2 sheets of mdf thick so that i could round over the speaker exit to give it a streamline look. the face is 12×48 and the total height with stand is roughly 4.5 feet tall. i painted the rear non visible areas of the OB tower with a black spray paint, and the face of the tower was a grey with a nice clear poly over it. no real previous knowledge of open baffle designs so i just kinda winged it on the dimensions.

Enclosure Assembly:
I didnt have any huge set backs why designing these towers. i wired the speakers up in a series parallel design to end up with a 4 ohm impedance. toughest part was probably figuring out how to attach the face to the base plate, which i do think turned out looking quite fashionable. i really liked how the speakers mounted from the rear, are replaceable, and how the wiring worked itself out. its very rigid wiring design which helps because its all exposed to the elements.

Crossover Design:
i used the premade PE 5khz 8 ohm hpf crossovers for the tweeters. no filters on the midbass drivers.

Conclusion:
i dont think ill ever go back to enclosed towers ever again. the bass from this open baffle is the best thing ive ever heard. its so smooth and seems to extend down to the sub 50 range, although i have not performed any formal tests to verify this. i think these towers will look great in my in laws living room.

Project Parts List: