Designer:
Bobby Kinstle

Project Category:
Car Audio

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
Despite having quite a large number of drivers and equal amounts of hype, I found the Bang and Olufsen system in my new Audi quite disappointing. Since most of the drivers are poor quality separates and many are odd sizes and some are 8 ohm, very little from the car audio world can be used. I replaced the 4×6″ 8 ohm horn loaded woofers and 4″ mids in the front doors, and the 6.5″ woofers in the rear doors. The rear door tweeters were just fine so I left them alone. The front pillar tweeters are rolled off at 10KHz inside the amp so replacing them won’t yield much benefit. The factory 10″ rear deck subwoofer was terrible and it can easily be replaced by most free air 10″ DVC 4ohm subwoofers. In the end I also added a Pioneer GM-D8701 amp to drive the sub tucked under the spare tire. The factory amp drove the sub just fine but I needed to reduce the low pass filter point to 45Hz.

Before starting the project I measured each driver in car the best I found with a Dayton Omnimic. To isolate the drivers, I put the microphone through the hole in the base of a clay flowerpot lined with foam on the inside and then wrapping a towel around the outside. Even then total isolation was pretty difficult on a couple of drivers, but I was able to get a useful view into the frequency range of each driver. One side note was the front door 4×6 woofers which are actually driven to 43Hz but can’t play anything below 58Hz. I only noticed because the 50Hz test tone on the Dayton test CD made that speaker vibrate.

Design Goals:
My design goals were to correct the harsh midranges, poor vocals, abysmal deep octaves on string instruments, and weak sloppy bass.

Driver Selection:
Front door woofers: 296-412 “Aurum Cantus AC-180F1 7″ Woofer”

Front door midranges: 264-1484 “Peerless by Tymphany GBS-115N25AL01-04 4-1/2″ Aluminum Dome Woofer 4 Ohm”

Rear door woofers: 299-609 “6-1/2″ Poly Cone Midbass Woofer 4 Ohm”

Subwoofer: Kicker CompC10 DVC 4Ohm

Enclosure Design:
I mounted the new drivers into the factory locations, so no enclosure design was needed. However the front door woofers required significant work which seems to fit in this section. The original speakers were rear facing into a horn that directed the sound towards the inside of the vehicle. After removing the drivers, I cut the top surface flat so I could mount a normal round driver onto it while utilizing the factory screw mounts and wiring harness connector.

The front door woofer also had only a 4×6″ opening in the grille, even though the fake grille marks are 8″ in diameter. I opened the closed holes above the new woofer so it wouldn’t be too restricted, but would still be strong enough to deflect any foot that bumped the door there when people were getting in and out.

Front door midranges bolted up to the factory location with spacers and some gasket material around the edges.

Rear door woofers bolted up with a standard Audi 5.25″/6.5″ speaker adapter ring.

Crossover Design:
I used the built in crossover points from the factory amplifier.

Tips & Tricks:
I strongly encourage reading my spreadsheet with my test data before starting down this project:
https://docs.google.com/spreadsheets/d/1ftkRt8rz1ZgtTtAs-NRYAIkHbtRuhX2cu702CeuqhVs/edit?usp=sharing

Add sound dampening material inside the panels while you are in there.

Conclusion:
Sound quality was massively improved. Bass guitar, cello, the bottom quarter of the piano all sound great. I had to lower the subwoofer crossover point because the Arum Cantus woofers played so well down the the factory cutoff of 43Hz that they were creating a strong overlap band from 43-70Hz. I should have made my life much easier if I had used a 6.5″ woofer rather than the 7″ as the woofer I chose required extensive cutting and grinding inside the door panel.

The peerless 4″ dome midrange is the real star of this show. The sound quality is simply unbelievable. The dome shape creates incredible off axis response that fills the entire front seat area with perfectly imaged sound FAR better than the fake 3D effect the car has build in. (I disabled all the 3D effect features that I could in software). The peerless midrange is bright and authoritative but NEVER harsh and brings out details in the music so tiny that you probably didn’t even know where there. For example, if I played “The Wind that Shakes the Barley” by Dead Can Dance, on the factory speakers you hear a woman singing punctuated by painful passages. On the peerless midrange, you hear the echos off the walls and instantly recognize it as a large church and her voice is always smooth and pleasing, even when she really raises the volume. I don’t think this driver gets near the love that it deserves.

The standard $6 6’5″ rear door woofer continues to be a crowd pleaser and meshes perfectly in the rear door with the rest of the system. Don’t be scared of the price. There’s a reason why you keep seeing this woofer in so many projects. I always keep a pair on hand in case I need another set and Part Express finally runs out of them.

Some day I may revisit this project to replace some of the surround speakers that can’t fully be turned off like the rear deck 4″ full range and the center channel 4″ woofer and 1″ tweeter. It’s low priority since these speakers don’t contribute that much to the overall project.

About the Designer:
I grew up in the Mojave Desert in a small community of scientists, craftsmen, and engineers. We were the kind of people who didn’t accept “it’s impossible” or “you can’t do that”. If I want something that doesn’t exist, I’ll just make one. Now I’m a thermal engineer in the computer industry and I currently hold six US patents.

Project Parts List:

Also Included:

Subwoofer: Kicker Comp C10
Subwoofer 3/4″ MDF mounting spacer
Rear door Metra 6.5″ adapter rings for VW/Audi

Designer:
wourmman

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Bluetooth Speaker

Design Goals:
Portable. Battery-powered. Compact. Great sound. Unbearably cool to look at.

Driver Selection:
Dayton Audio ND65-4 2-1/2″ Aluminum Cone Full-Range Driver
Dayton Audio ND90-PR 3-1/2″ Aluminum Cone Passive Radiator

Enclosure Design:
3/16″ acrylic

Enclosure Assembly:
Laser-cut acrylic; solvent welded; air tight.

Crossover Design:
N/A

Conclusion:
Learned (the hard way) NOT to place drivers behind the front panel — speaker diffraction really is a thing!
The Dayton Audio parts matched up extremely well, and work extremely well.

About the Designer:
Retired USAF engineer. Maker.

Project Parts List:

Designer:
Greg T

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
I used the Denovo enclosure, the plan was just a two way design with the plan to use them alone or as fronts in surround sound. I used the DC28F-8 Dayton Audio tweeter and the HiVi M6N. They both have a sensitivity of 89 dB so they would be a good match and not require an l-pad to balance the tweeter. When I modeled it in BassBox I got an ideal volume for a ported setup similar to the 0.56 cubic foot boxes if I did not use polyfill so that is what I went with in this case. I tuned the port to 36 Hz. for the smoothest response. On paper I would have a roll off at 61 Hz for the F3 in with the M6N.

Design Goals:
I intended this to go with a turntable and a small subwoofer, but was so happy that in the end I have used them as my front channels for a 5.1 channel surround sound system.

Driver Selection:
275-070
297-441

Enclosure Design:
I used a ported box, part number 300-7064. I also used a ported setup with the port tuned to 36 Hz.

Enclosure Assembly:
The knockdown boxes are simple to put together. I ended up finishing them in white, the most complete image with this is just before the final coat.

Crossover Design:
I chose a crossover point of 2000 Hz, Linkwitz-Riley, 2nd order. And I did use a Zobel for the woofer to help smooth it out. I ran into some cone break up in the range of 1000-2000 Hz that became a hump in the response with my crossover point. So in the end i added a notch filter as well to target 1500 Hz and take the edge off the mid-range.

Tips & Tricks:
In my case I found the tweeter did not need to be out of phase for the second order crossover. Acoustic results varied form the planned design when tested with the Omnimic and I had a dip at 10 KHz like it was out of phase. I verified that I had them wired correctly and then rewired to normal polarity and found the dip disappeared. The response chart is before and after i made that change.

Conclusion:
Happy with the results overall. I would have put the tweeter a bit closer to the woofer if I had to do it over, but with the room they are in the stereo imaging was not really impacted nor the perceived center point of the speaker box. I found the lows better than a set of old Sony towers I used for my surround sound so I swapped them out. After breaking in the woofers I find that they are meeting the goal for low end, but now that I have them in surround sound that is less important. I was so happy with the tweeter’s sound that I swapped out the tweeter in my center channel with the same model to have a more cohesive sound in my front three speakers.

About the Designer:
I have been a technical adviser for Parts Express for nearly 5 years.

Project Parts List:

Designer:
Greg T

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
I have several old Samsonite luggage pieces that i have not used for years. They are also not as great for travel compared to a modern bag so I decided to upcycle them to be boom boxes. This was the first attempt.

Design Goals:
I wanted a portable Bluetooth setup that I can use around the house.

Driver Selection:
267-4327

Enclosure Design:
Small vintage Samsonite suitcase with some egg crate foam to deaden the walls a bit.

Enclosure Assembly:
I removed the inner pant bar and one of the pouches for small items like socks. I left the other and use it as a cubby for the ac adapter and cables so it is always ready to go. I cut the holes for the speakers and mounted some egg crate foam inside. The holes for each item on the side were all various diameters of drill bits so simple to setup and prepare.

Tips & Tricks:
I chose to use the KAB-INT for the USB charger, and I used an extension cable to connect it to the outside of the cabinet and avoid the odd cutout of that board. I extended the AUX input as well but do not use either. In the next project I may not use either.

Conclusion:
The frequency results using the IMM-6 mic and an Android app show an acceptable mid range response for the application. Bass response is limited since I used car audio speakers and enclosed them but it does fine overall. It is also not a large suitcase so i knew it was not going to go exceedingly low. I have a larger case for the next project that will focus more on a wider response curve. Battery life is 18-20 hours on background listening levels in my home as I work on projects. Less of course if I am pushing the volume, and I can always add another battery board later if I feel the need.

About the Designer:
I am a Technical Adviser for Parts Express for nearly 5 years.

Project Parts List:

Designer:
Mark

Project Category:
Freestyle Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
My first concerted start to finish woodworking project. Wanted something small and classy for one of our bedrooms. Had the PS95s in their boxes ready for a project. The rest is history.

Design Goals:
A small sealed enclosure suitable for the PS95s.

Driver Selection:
Dayton Audio PS95-8 (295-349)

Enclosure Design:
I had a set width and height in mind, and tweaked the depth of the box to match the ideal sealed volume specs for the drivers. I used a roundover on the top and side edges, and left the bottom and back square (a direct inspiration from the Cordelia build posted here, so thanks!).

Enclosure Assembly:
The enclosure is 1/2″ birch plywood, with a 1/2″ Douglas Fir baffle. Drivers are recessed about 1/4″. The rear is 1/2″ MDF for now – I plan to update the box with internal amplification later, but for now it’s being powered by a small external bluetooth amplifier. I used a small amount of PolyFill just to make sure the wiring didn’t rattle in the box. I finished the enclosure with some small rubber feet and speaker terminals on the rear (not shown), and a quick coat of satin varathane.

Crossover Design:
N/A. Running these drivers full-range as intended.

Tips & Tricks:
As my first woodworking project, I learned quite a lot in the process. The router circle jig made recessing the drivers pretty easy once I had the radius and depth right (practice on MDF first). I’d probably not use the roundover style on plywood again, as it exposed the ply more roughly than I’d wanted. I’ll go back and re-sand and seal the enclosure, as I’d like it all to be a bit smoother.

Conclusion:
Very impressed by the sound from these small drivers. I find the bass starts dropping off around 110Hz (more or less on par with the reported specs for a sealed box, possibly a bit lower due to the light stuffing used?). Sound quality in the acoustic instrument and vocal range is fantastic to my amateur ears in this small-room, moderate-volume application. I can see why people like these drivers so much.

About the Designer:
Longtime speaker junkie, first-time woodworker. Hopefully the first of many projects.

Project Parts List:

Designer:
JoeR

Project Category:
Loudspeakers/Cabinets

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
It was time to refresh my mid-high PA cabinets. While researching the causes of listener fatigue, I found the Econowave blog at PE and Redstate audio, and the unique crossover design described there, which was modeled with the free “Windows Passive Crossover Designer”. If you have not experimented with WinPCD, consider downloading it and giving it a try! You will be able to quickly simulate many designs and see the results visually, without having to physically build them. This will save a great deal of time and money, and you can zero in on your optimum design much faster. There are two computer files required for each driver used, the .frd frequency file, and the .zma impedance file. There is also a place labeled “SPL adjust” to enter the difference in efficiency (8dB) between the woofer and compression driver. Be sure to do this or your curves will not match up properly.
The Econowave blog also discusses the importance of elimination of any unwanted reflections in the HF subsystem. This cabinet design uses a split baffle to move the horn forward and does not have any internal cabinet edges around the horn. The internal geometry of the horn itself also is a consideration. (The blog discusses horn geometry and in particular, horns with parallel internal walls in the throat area, and the detrimental internal reflection that could occur.)

Design Goals:
1. Great Sound (obviously) with minimal listener fatigue.
2. Water resistant design (brief summer shower should not ruin the woofer cones)
3. 100 dB efficiency with 300w-400w program power handling
4. Full-range response for smaller events, mid-high performance with subs for larger ones.
5. Medium throw capability (90 degree horizontal coverage now, 60 degree in future design)
6. Trapezoidal cabinet with vertically-aligned voice coils, and closely-spaced drivers
7. Reasonable weight around 60 lbs.
8. Readily available parts from Parts-Express naturally!

Driver Selection:
The weight requirement suggested a neo woofer, and I chose the Eminence Kappalite 3015 neo woofers #290-597 based on the specs and smooth response of this driver, and also my positive experience with the 3015LF version of the same woofer that I use in my subs. Eminence provided the .frd and .zma files for modeling the woofer in WinPCD. Woofer cone was given 2 light coats of “Wet Look” coating #340-512 using a very soft 1” paintbrush to provide water resistance.
For the HF driver, the B&C DE250 #294-605 got the nod. WOW- I CANNOT SAY ENOUGH GOOD THINGS ABOUT THIS DRIVER! This level of clarity and detail is astonishing in a compression driver. Another huge plus is that these drivers are essentially FLAT, and do not require equalization in the crossover, just level matching with the woofer. PE provided the .frd and .zma files for modeling the driver in winPCD.
The horn lens chosen was suggested in the Econowave blog, and is the B-52 PHRN-1014 #299-2303 and is an absolute bargain at PE. This is a simple, throatless 90×40 design with no parallel internal walls.

Enclosure Design:
Cabinets were constructed from plywood, with a trapezoid shape for horizontal arrays when needed, and the internal volume (2.8 cu.ft.) recommended by Eminence for their “medium” sized cabinet and tuned to 49hz. I used “Sandeply” plywood from Home Depot and while ¾” thick, is considerably lighter than poplar or other hardwood plywood. While it is relatively void-free, the internal layers only seem to have the density of balsa or basswood. Screw holding power is less, so be sure to use hurricane nuts #081-1082 or Tee nuts to mount your drivers. The plywood seems to be fairly non-resonant like MDF, but stronger and much lighter than MDF, but weaker and more flexible than poplar or pine plywood. (If strength is a major concern, then use heavier maple or birch veneer poplar-core plywood instead.)

Enclosure Assembly:
Cabinets were assembled with construction adhesive and 19 ga staples and screws, sanded and given 2 coats of DuraTex #260-101 textured coating for a professional appearance and tough, low-maintenance, water-resistant finish. Soap and water cleanup is a huge plus with this product. Because the front surface of the horn is flush with the front edge of the cabinet, no grille is installed in front of it. The woofer has expanded metal painted black installed in front of it for protection. Metal cabinet corners and handles finish off the cabinet.

Crossover Design:
The crossover was built with components from PE, and includes all air-core inductors. Technically the crossover is asymmetrical with 12 dB/octave for the woofer, and 18 dB/octave for the tweeter, and crossover frequency is about 1700hz. Woofer section is a hefty 2mH 14ga air-core coil, and 15uF cap. Tweeter section has a 5 ohm series resistor network, then a 5uf cap, 0.6mh coil, 20uf cap, and a 5 ohm resistor network in parallel with the driver. Since these cabinets will be used professionally, each resistor network has a power rating of 50 watts or more. This crossover topology will work the amplifier a little harder at high frequencies than a traditional crossover with it’s rising impedance at high frequencies. But any back EMF from the compression driver will be dumped primarily across the parallel resistor network for dissipation, instead of across an inductor, where it could cause interference. Driver protection is provided by a polyswitch paralleled with an Eminence PX bulb #290-659.

Tips & Tricks:
“Room EQ Wizard” was installed on a laptop and used with a dBx calibration microphone to verify that the cabinets were performing as predicted by the simulation software. PE has several measurement microphones you can use if you do not have one already. You will need Java on your computer to run REW, and a reasonably decent sound card for accurate measurements. My measurements were made in a non-anechoic environment so the curve is not smooth in the low end frequencies. But I was more interested in the behavior around the crossover frequency, and the overall balance between the woofer and compression driver, and these both look very good. Graph shown is an actual measurement of the cabinet with 1/24 octave smoothing. There are many other useful features in this program, and it is a welcome addition to my audio toolbox.

Conclusion:
All in all, these cabinets are easy to transport and deploy, a pleasure to listen to, and a huge improvement in sound quality and appearance compared to the cabinets they replace. Thank you Parts-Express!!

About the Designer:
Retired computer network engineer, and audio enthusiast for the last 50 years!

Project Parts List:

Designer:
Chris

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
This build was my first attempt at building a speaker box. My previous store bought portable speaker gave out so I decided to make one rather than buy another. It is a ported box that contains a 5” midrange and 1” tweeter that can be powered by rechargeable battery pack or ac adapter.

Design Goals:
Needing a speaker that could be portable my goal was to make a box that was small enough to carry around but would still sound good.

Driver Selection:
The 5 inch midrange subwoofer part 295-426 will cover from 50 to 7,000 hz.
The 0.8 inch tweeter part 292-556 covers 1.2 khz to 22 khz. Both are 8 ohm speakers that handle 50 RMS.

Enclosure Design:
The box was constructed from 3/4 inch MDF and covered with a cherry veneer. It has a 1×4 inch port and a stainless carry handle. Measuring at 9 1/2” W, 12” T, 5 1/2” D weighing about 10-12 lbs. Its braced and polyfilled.

Enclosure Assembly:
Putting together the box was not difficult. After cutting all the dimensions I screwed it together with 1 1/4” pocket hole screws. For the bracing I cut out a circle in the middle of a left over piece of MDF then cut that in half. All seams inside the box were covered with silicone with exception of the back panel for access. Its filled with a couple of hand fulls of polyfil.

Crossover Design:
My crossover point is at 4000 khz.

Conclusion:
I am overall pleased with how it came out. The music is clean with crisp highs. It has moderate bass, about as much as you’d expect from a 5 incher. For a total cost $220 I built my first portable bluetooth speaker that I can take around where ever music is needed to fill a room.

About the Designer:
DIY’r with some woodworking experience.

Project Parts List:

Designer:
Shannon Ley

Project Category:
Headphones/Accessories

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
Under $100

Project Description:
3D printed bluetooth headphones with volume, track and play/pause buttons and a microphone to take calls. And they sound great too!

Design Goals:
The objective was to create 3D printed headphones that rival great store-bought ones for sound and ease of use. All the parts had to be readily available and affordable.

Driver Selection:
Dayton Audio CE38MB-32

Enclosure Design:
3D printed ABS

Tips & Tricks:
Out of the box the Dayton Audio CE38MB-32 are a bit bass heavy in this configuration. A bit of plasticine over the all except one of the drivers rear holes made them sound a lot better.

Conclusion:
The headphones sound great, look good and have intuitive controls.

About the Designer:
Engineer, tinkerer, small business owner.

Project Parts List:

Designer:
Jeff

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
I used part # 320-636 TPA3116D2 Class D 2.1 Amp Board 2X50W + 100W with Bluetooth 3.O and backlit LCD screen with part# 325-204 , 12VDC Output Power/ 18650 Battery Charger Bundle. Part# 275-106, Dayton Soft Dome Tweeters. Infinity 6X9 Automotive speakers.

Design Goals:
Make a Bluetooth speaker box someone could hear from miles away! Haha!

Driver Selection:
I used Part# 275-106 Dayton Tweeters and my own Infinity 6X9 speakers.

Enclosure Design:
I sprayed a base coat of tan on and then air brushed the box to make it look like wood grain and then sprayed 4 coats of clear on top of all of that.

Enclosure Assembly:
The box is made of MDF Plywood and formed with clothe and fiberglass and bodyfiller.

Crossover Design:
No crossover used.

Tips & Tricks:
Really no tips or tricks. Plug n Play mostly.

Conclusion:
This is one LOUD Box! And think the board has a place to hook up a subwoofer. I will update if I decide to get a sub.

About the Designer:
I like messing with electronics.

Project Parts List:

Designer:
Kenny

Project Category:
Freestyle Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
Stereo build from ground up.

Design Goals:
Christmas present I built for my 10 year old nephew. Wanted to give him the stereo I would have loved at that age.

Driver Selection:
HiVi B3N 3″ Aluminum Driver Round Frame
Part # 297-428

Enclosure Design:
Home built from Maple.

Enclosure Assembly:
I’m quite proud of the finish on this. First I brushed a layer of yellow watercolour paint on it, then I put a clear coat on the bare maple, then sprayed it with an aerosol “candy red” I found at a hardware store. This way I could see the wood grain through the paint, but still gave it the flashy look every kid wants. I was hoping to achieve a bit more orange, but the red went over really well too.

Conclusion:
There was lots of little things I tried, including hiding the LEDs on the rear side of the front face by very nearly drilling through the face from the rear, then just getting a glow from the LEDs. This worked fairly well. A few things I’d have done different would have been a lighter enclosure, and maybe gone a bit bigger and done vented enclosures as well. Overall I was very pleased and so was my nephew!

About the Designer:
Home builder, just for fun.

Project Parts List:

Designer:
John Murdock

Project Category:
Portable Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Mk boom kit that I made my own cabinet for

Design Goals:
Vintage modern with a twist

Enclosure Design:
Mdf and tiger oak

Enclosure Assembly:
Laminated MDF

Tips & Tricks:
Lots and lots of sanding lol

Conclusion:
I think my design turned out well with a vintage modern style

About the Designer:
Beginner with basic hand tools and ambition

Project Parts List:

Designer:
(custom) MK BOOM

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
MK BOOM Laminated

Design Goals:
Quick and easy

Conclusion:
Nice beginner kit

About the Designer:
All wood shop in Allentown

Project Parts List:

Designer:
safehans

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
I wanted to build computer speakers that were small and could be built extremely quickly.

Design Goals:
Very small, no electronics, quick build yet decent sound decent at least when pointed straight at you 2 feet away from you

Driver Selection:
From the design goals you can see there aren’t any drivers that would really perform under these crazy conditions.
So with some compromises I picked Dayton Audio ND65-8 2-1/2″ driver that promises to perform fairly well.

This would be used in full range duties with no crossover.

Enclosure Design:
Since I wanted something really quick, I didn’t want to build the cabinets from scratch. My previous builds are still in Garage after a thrid coat of paint and after months of work.

I also did not want Munny dolls funny looking cabinet. So I ordered a few wooden vases from Amazon that had roughly the right size and volume. Among these were Oval mango wood vase, banboo cylindrical vase etc.

I chose the Mango oval vase for the project eventually as no cuts or mods were needed to this.

Enclosure Assembly:
Enclosure is built from a 5″ outer diameter oval (or ellipsoid?) vase from Amazon that has roughly .015 cu ft internal volume. All I had to do was to sand the front face over a belt sander until the opening was exact size needed for this driver. I had to shave off 3-4mm of material at max.

Rest of the assembly was super quick with two holes in the back for binding posts and two on the bottom for a stand.

Stand is built from a stainless steel wire that keeps them pointed up to the ears

Finishing was done with Automotive spray paint in Piano black. Single coat did the trick.

Crossover Design:
No crossover was needed

Conclusion:
These actually surprised me after first listen. I actually thought my bigger bookshelves were ON. When they pointed straight at you and aren’t too far from you, they almost sound like real monitors. Low end is actually acceptable given that these are 2.5″ drivers in a small sealed box. They don’t really perfrom well over 15K hz which was expected

About the Designer:
When given a choice to buy something for really simple and cheap, he always opts to build something complex and expensive. How else would he learn!

Project Parts List:

Designer:
Dave M

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
A Blast Box Build.

The CNC routered cabinet panels are very precisely made. Every rabbet is perfect, and the screw holes are perfectly placed. After sanding, it looked good enough for several coats of polyurethane finish, rather than paint.

Grille frames were made from 2- thicknesses of 1/4″ lauan plywood laminated together, cut out, and gone over with a roundover bit. Burgundy/Beige cloth is used. Grille guides are used to attach to the cabinet.

Because of the cloth grille covering the back, the charging jack had to be re-routed to the side.

A metal dish was used for the charging jack, charging indicator LEDs, battery condition LEDs, battery condition pushbutton, and two RCA jacks for a Line In.

Design Goals:
A good-sounding kit build, rugged enough to use in the workshop.

Conclusion:
It’s a great sounding unit!

About the Designer:
Hi, I’m Dave.

Project Parts List:

Designer:
Ryan Michael Clark

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Identically matched left, right and center channel speaker for my living room. Basic 2-way design using all Dayton components: 8” paper reference woofer, DC28 dome tweeter and 3K crossover. 0.75 cubic foot sealed cabinets.

Design Goals:
I really enjoy both music and movies and wanted to upgrade my front 3 from my Polk set up that wasn’t really a matched set. I am not an audiophile and don’t have testing equipment, but the Polk speakers just seem to be missing that definition that I set out to get from this build. The Polks are not bad speakers, but I am hoping for good to excellence sound quality speakers. This was my first full range speaker build. I bounced around a while with different designs and ultimately decided on 3 identical “large” bookshelf speakers, which from what I have read is idea for an LCR set. A special thanks to PE techs that helped guide me on this design.

Driver Selection:
275-070
295-577

Enclosure Design:
I ended going with sealed enclosures as these speakers will likely spend their entire lives playing ~80 Hz and up (receiver crossover) and a larger ported enclosure wouldn’t add much value for my application.

Enclosure Assembly:
Used 3/4 MDF, partial sheet left over from last project. I also was able to reuse some panels from two sub cabinets I was going to toss out.
Joined sides, top, bottom and baffle with glue and pocket screws. Mounted the back with glue and finishing nails.
Painted with interior while paint to match rest of system.

Crossover Design:
Prefab Dayton 3K crossover. Designing and building crossovers seems a little beyond my current capability at this point. In retrospect, the 3K crossover may be a little to high but the speakers sound great so I probably will not change them.

Tips & Tricks:
Slow down! I think my biggest challenge is that I try to speed through projects, excited about the finish line. The problem is that I often don’t spend time on the finishing details and regret it later. I have a toddler which limits my hobby time, so I would set short-term goals for each available time window with no expectation of a completion date. Example: Saturday – cut all pieces. Sunday construct cabinets. Lunch break Monday – predrill all hardware holes…
Plan your material cuts, always trying to make all common dimension cuts while your saw is set to that length, so you have as little variation as possible, not to mention a time saver. I lay out all my cabinet pieces on my material sheet sizes so I have a cut plan (see my example in photos).
When constructing your cabinets, yield any flaws to the least seen part. In my case my baffles ended up about 1/32” too small. I tried to get that gap on the bottoms.
This time I predrilled all pilot holes (drivers, terminals, grill mounts) so that after I painted/finished I would have no dust and debris in my cabinets. This make the last part nice as I could finish up in the house without a mess.
I also read that if you use silicon to let the cabinets air out well before mounting the drivers as fumes from some sealants may damage drivers.
I used the PE grill kit linked below. It was really good kit despite my terrible skill with fabric. If you use this kit make sure to measure it out. I was able to make all 3 grills with the frames of one kit and only had to purchase 2 addition corner kits.

Conclusion:
Total cost (components and wood) for me, after getting some items on sale, open box, using coupons, etc., was less than $400! I feel my $400 speakers easily compete with one’s cost several times this. I am very pleased with project sound and finish. They drivers have less than an hour of play time. I know they will sound better as they break in, however, they are already noticeable better than what I had. Just clearer sounds and I can hear more content. Also, the off-axis is significantly better. Also, the cabinet is large enough that I can still add a port to get a little bump if I would like later. We will see…
Overall, I am ecstatic with the project. It was enjoyable, looks and sounds great. Already have plans for a couple more full-range speakers.

About the Designer:
I have always been an aspiring audiophile, although I don’t consider myself one. I am just a guy that loves music (listening and making), movies and building things out of wood. I still have my Infinity SM-62’s I bought out of a Crutchfield catalog in the early 90’s (~14 years old).
I am already planning a future project that I am calling “Old Schools,” which will be my recreation of the Infinity SM112 that I so wanted as a teenager. My versions will sound better

Project Parts List:

Designer:
Bobby Kinstle

Project Category:
Freestyle Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
Last summer, after my son’s sixth birthday, he casually asked me for an alarm clock to wake him up in the mornings before school. Over this same summer he really started taking an interest in music as well, so I decided instead of buying an off the shelf alarm clock, I’d build something special for him to use and enjoy for many years to come. It started out as an FM radio, and then I tried to do HD radio only to discover its impossible for a lot of really terrible reasons, and finally settled on building a clock with amplified speakers with analog an Bluetooth inputs so that it would work with an external source, in this case an amazon echo input, so that the music source can keep pace with the inexorable forward march of technology and digital media delivery. From here the project was quite simple and I let my son pick out any digital clock that he liked to mount in the box.

Design Goals:
The design goals were to tell the time, play high quality music, be compatible with multiple music sources, and have a programmable alarm clock. I also bought the volume knob for the amp so I could set an upper limit of loudness my son could select with the external source. If Bluetooth proves unreliable, I can use the analog input instead.

Driver Selection:
Given the extreme small size of the enclosure driver choices were limited. I originally considered a 2.1 design with 2 way stereo mains and a powered subwoofer, but the box was just too shallow to mount a speaker of sufficient quality. After running many different calculations on speakers that would fit, I realized the Dayton ND91 aligns well with using passive radiators. I’ve never used a passive radiator before, and the concept was a bit daunting, but after reading up on the math involved, I was able to find a nearly perfect match between using a pair of ND91’s and a Dayton Designer series 5” passive radiator with 7.2g of weight added. The ND91’s long excursion lets them belt out shocking bass even as low as 55Hz but they do pay a penalty in reduced midrange performance at high volume levels and heavy bass. This is a common issue with long throw woofers and something you’ll just have to accept. The effect isn’t deal breaking and frankly not an issue at alarm clock listening levels.

When it came time to pick the tweeter there were many good choices, but I decided if I’m going exotic with a passive radiator, why not jump right into the deep end with an AMT tweeter too? The AMT tweeter had a 3dB higher sensitivity than the ND-91 woofer, so I used the 8 ohm tweeter with the 4 ohm woofer to balance it out without burning off any power with resistors. Sweeps transition very smoothly between the woofer and the tweeter. I expected the AMT tweeter to be super sharp and possibly harsh, but it turned out much smoother than I expected. This combination is clear but the response is pretty flat and not overly bright as small speakers sometimes can be.

Enclosure Design:
The enclosure is based on a birchwood box I found while cleaning up my mom’s estate. It had a nice finish on it and was very solidly built. It appears to be some sort of document filing box as the inside is exactly letter sized and it had a plastic pull handle on one end (which is now the bottom). A sliding panel at the other end allows access to the inside and fits very well but needed some gasketing to make a good seal. In the end I needed to lock it down very tightly because the ND91’s can generate impressive pressure levels inside the enclosure that bounced the lid around pretty hard and sounded like popcorn popping in a kettle.

Since the original finish was scratched, I decided to refinish the box. This turned out to be a much bigger pain than I expected. The original finish was a color gel stain sprayed on top of a hard clear coat. Chemical strippers and a lot of scraping eventually got them off. Since the box was small, I attached a few sheets of sandpaper to a flat granite surface plate and sanded the sides *extremely* flat. Nothing says quality like perfect flatness. Staining was also problematic as the birch doesn’t absorb stain very well and I ended up using a gel stain finish. I’m not fully happy with how that part turned out but my son loved it and that’s really what mattered. After that I applied 4 coats of semigloss lacquer with a light sanding in between coats and a light polish with fine steel wool at the end.

Enclosure Assembly:
After cutting holes for the drivers, connectors, and the clock I secured the crossover boards to the bottom with generous helpings of hot glue. The power and AUX input jack screwed into the back side and sealed with hot glue. The amplifier board secured into the rear wall with wood screws and standoffs as well as the volume knob. I added a DC/DC converter to accept wide input DC and output 5V on a USB plug to power the clock and secured it with Velcro if I need to replace it later. The clock assembly fit into the slot and I used generous amounts of black silicone caulk to seal the edges on the back side. The passive radiator is glued on the backside with Loctite construction adhesive. Lastly, I secured the drivers with brass screws to break up the overwhelming blackness of the project.

I realize the glued items sounds like a one way trip but since I can only work on things through the small access door, it really was the only way to secure certain things.

Crossover Design:
For the crossover I made a simple second order (12dB slope) 2 way Butterworth design set to 6Khz. Since the tweeter and woofer are different impedances, I had to adjust the component selection accordingly, however as I mentioned above, I did not use any impedance matching resistors as I was able to make the SPL rating the same by using different impedance drivers. I hate using resistors in crossovers and especially hate burning off power in a small enclosure that already contains an amplifier. I would not run a slope less than 12dB with an AMT tweeter. The coils and caps were glued to FR4 PCB material using an industrial strength hot melt glue gun. This is much stronger than craft hot glue but be warned it will blister your skin if you touch any of the liquid product.

Tips & Tricks:
1. Use the highest voltage power adapter the amp can support to increase dynamic headroom on class D amps. Use the volume as a gain control by setting the source to it’s highest level playing music, then adjust the amp volume knob to be a little louder than you’d ever want it to be, and the only use the source’s volume control to adjust playback after that. This will give you the lowest idle hiss from the amp while supporting the range you want and not run the risk of clipping.
2. Dremel makes a jig for cutting grooves and circles with their rotary tools. This jig is super sloppy and should not be used to cut anything other than drywall and even then you’ll need to cover it with a flange. Use a real router for cutting wood. The results are so much better, no matter how inconvenient it is.
3. Hole saws can cut a pretty clean hole if you clamp the work down and load the hole saw into a drill press. Take your time.
4. Confirm your wood is compatible with your stain BEFORE applying it to the project.
5. Solder connections when possible. All others crimp tight fitting connections.

Conclusion:
The project turned out very well for the effort. It plays far louder than any alarm clock has any business playing and at far higher quality than even premium alarm clocks on the market. I wouldn’t call it high fidelity, especially at high volume levels, but in general I’m very happy with it. It plays pretty solid down to 55Hz. Having the speakers on the sides of the box means placement is critical. It works best in a corner, or in the middle of a wall and has no difficulty filling a bedroom with music. My son is ecstatic about the clock, and he loves using the voice controls to program it and play music.

Here are a couple of videos I made with a good quality microphone to demo the system.

About the Designer:
I grew up in the Mojave Desert in a small community of scientists, craftsmen, and engineers. We were the kind of people who didn’t accept “it’s impossible” or “you can’t do that”. If I want something that doesn’t exist, I’ll just make one. Now I’m a thermal engineer in the computer industry and I currently hold eight US patents.

Project Parts List:

OTHER COMPONENTS:

9-36V Buck voltage regulator with 5V USB output
5.5mm Power jack threaded panel mount receptacle
Scientific brass slotted weight, 5g
Amazon Echo Input
Walmeck DS3231 DIY Dot matrix clock kit
16Ga speaker wire
4 Screw down rubber feet
Lots of various bits and bobs

Designer:
geoff hooker

Project Category:
Freestyle Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
full range DML speakers with equalization

Design Goals:
the goal I wanted is to design these speakers to have a balanced sound without excessive treble and poor bass and to sound good on most types of music. I have been experimenting with dml speakers for many months and have come up with these.

Driver Selection:
The drivers I used are the Dayton audio DAEX25FHE 4 OHM 24w types. I would highly recommend them for this project. I have tried other types and think these are the best sounding.

Enclosure Design:
You will need 2 sheets of 5mm thick 20×30 inch foamboard and 2x100mmx3mm thick MDF discs which you can buy at art supply shops. They need to be drilled first for the 4 nylon mounting bolt holes and after marking the position of the driver drill 5mm holes around the disc-I found this improved the treble. Prime the center with PVA glue to improve adhesion of the driver then stick on after drying. Mount these to the panels slightly off center with the bolts and nuts but DO NOT glue them on. It is very important that the discs fully contact the panel and have a smooth surface.

Enclosure Assembly:
A pair of simple stands will need to be made to hang them on. I used some string glued on the back and hooks.

Crossover Design:
The equalization crossover is a simple R C L network in series with the driver. The values are R=12ohm C=2.2uF L=3mH.See picture.

Tips & Tricks:
The 12ohm resistors can be changed to 6ohm to lessen the EQ curve depending on your preference and room acoustics.

Conclusion:
I listen to these most nights and am very happy with the sound. I think these sound way better than budget box speakers. I mainly listen to jazz and easy listening.

About the Designer:
I am a keen audio diyer and am always experimenting and making amps, preamps etc

Project Parts List:

Designer:
John

Project Category:
Loudspeakers/Cabinets

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
I designed and built a medium size mini-tower. I had a number of Parts Express components that I combined to make this 8 inch 2-way speaker. We wanted something that looked nice and could fill a room with nice background music.

Design Goals:
Moderate size, decent bass response, clear treble, attractive woods and visual appearance.

Driver Selection:
Woofer- TC-8034 8 inch 4 Ohms. Tweeter- Selenium ST-200, 8 Ohms. These drivers were selected for smooth response, and relatively high SPL.

Enclosure Design:
The box was designed using the Loudspeaker Design Cookbook software package. The external dimensions are 24Hx12Wx15D. These dimensions would be nearly-optimum for the woofer, with a short port length predicted. The cabinet wood is solid 3/4″ Red Grandis, with 3/4″ Leopard wood for the center stripe, with a Black Walnut trim strip around the outer perimeter to hide the joints. The back panel is 3/4″ MDF.
The 2 inch port was selected so that the port length was short to minimize any breathing effects. The actual port lengths were 2.5 inches for one cabinet, and about 2.7 inches for the other cabinet (due to variations in the actual woofer stiffness, I believe).

Enclosure Assembly:
All of the “nice” wood was planed to 3/4″ before starting. The front and top/bottom panels were made by joining ~6 foot long pieces of Red Grandis and Leopardwood, observing the grain orientation, using biscuits and then cutting to size. The side panels are biscuit-joined Red Grandis, about 8 feet long, and cut to size. Medium biscuits were used throughout. The holes for the speakers were cut with a plunge router and Jasper cutting guide. The woofer is back-mounted, so I used a 3/4″ quarter-round to smooth the top inside edges. Because the speakers align to the center stripe, accuracy of the hole locations is important. All of the interior joints were reinforced with 3/4″x3/4″ pine. The key issue is to keep the edges square, and move quickly when assembling as the PVA glue sets quickly. Cross-corner measure to ensure squareness. Use lots of clamps.
The walnut trim strip was inlaid with a 1/2″ router bit, set to slighter shallower than the thickness of the walnut. The walnut was trimmed with a small hand plane to precisely fit the grooves. To bend around the corners, cross-grained walnut was soaked in hot water for 20 minutes, then glue applied and slowly bent the wood around the corner curve to prevent cracking. Blue painter’s tape was use to hold the corner inserts in place until the glue dried.
The box was sanded sequentially from 80 to 120 to 220 grit using an orbital sander. The finish is 4 coats of Minwax Polyurethane Clear Satin, lightly sanded with 400 grit paper between coats. The back panel was drilled for the L-pad and mounting screws with countersunk holes. Flat black enamel was used for the back panel finish.

Crossover Design:
I used ERSE (http://www.erseaudio.com/) as a starting point.. I selected a Linkwitz-Riley configuration. varying C and L values to get a crossover frequency about 3200Hz, with 12dB per octave slopes. Since the actual values (C1=4.4uF, L1=0.56mH, C2= 8.8uF and L2=0.28mH) are not available, I trimmed the components using additional capacitors in parallel and adding/removing wire from the coils to get precise values
All capacitors, resistors and coils are from Parts Express. A Zobel R-C series network was added across the woofer to smooth response (http://diyaudioprojects.com/Technical/Speaker-Zobel/). These component values were 9uF and 9.5Ohms. Crossovers were tested and tuned individually with a sweep generator and oscilloscope. The actual crossover points are about 3250Hz. The crossovers have point-to-point wiring on terminal blocks, mounted on 1/4″ plywood, caulk mounted to the back panel (no vibration), with screws (just for insurance).

Tips & Tricks:
Use alignment jigs when using biscuit joints. Lots of Tite-bond in the joints, wipe off the squeeze-out. Add 3/4″ reinforcement along all of the edges and the back panel supports. Wire internally with polarized plugs and color coded wires in case of repair.

Conclusion:
The speakers are attractive looking, and sound really smooth. Still trimming the tweeter L-pad for aural balance to our ears. They are not as efficient as some of my other larger designs, but quite adequate for the demands.

About the Designer:
I am trained as an EE from Michigan State University, with MS and PhD in Materials Science from MIT. I made my first speakers for a friend about 50 years ago. I have built more than 50 designs, including exact replicas of Klipschorns, JBL L200s, and Voice of the Theaters. My favorite drivers are horns for mid and high ranges, mostly from JBL, ALTEC, Selenium. I have experimented with all types of tweeters, but keep coming back to horns for their clarity and high output. I also rebuild VOX guitar amplifiers from the 1960’s and 1970’s, improving the electronics and restoring cabinets to “as close to original” as possible.

Project Parts List:

Designer:
RB

Project Category:
Subwoofers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$500 – $1,000

Project Description:
My brother needed a good subwoofer for his living room, and this is what I came up with.

Design Goals:
Be able to play loud.
He has a hyperactive dog so I tried to build something that wouldn’t be prone to damage.

Driver Selection:
Used the 8 Ohm Dayton Reference 12″ woofers.

I wanted the extra power handling, but still wanted a 4 Ohm load which was the main reason for using 2 woofers.

Enclosure Design:
I used the recommended volume for a sealed box. The interior is split into 2 compartments just for the added bracing.

Enclosure Assembly:
Entire enclosure is built with doubled 3/4″ MDF.
Added grills to protect the woofers. The mounting hardware didn’t work with the reference woofers but figured out a way to mount them.
Glued everything together and used a 3/4″ roundover on all the edges.
Primed then rolled on DuraTex to finish it off.

Conclusion:
Im happy with the way it came out. I didn’t realize how heavy this was going to be (well over 100 lbs.), needed 2 people to move it with the woofers installed.

About the Designer:
I enjoy audio and I enjoy building things so this is something to occupy my time.

Project Parts List:

Designer:
John Murdock

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Blast box build with a fun finish.

Design Goals:
I wanted a cool looking shop speaker with an old hotrod vibe.

Driver Selection:
300-7162

Enclosure Design:
Standard blast box enclosure

Enclosure Assembly:
Glued plywood

Crossover Design:
Standard blast box hardware

Tips & Tricks:
To get my finish I painted a primer coat. Then the three colors layered. I sanded thru to get the vintage look. Then sealed it all with a satin poly.

Conclusion:
This was an easy yet satisfying build.

About the Designer:
Just a big kid that plays in my shop.

Project Parts List: