Designer:
bwguyer

Project Category:
Tower Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Balanced and accurate 3way for medium to large rooms

Design Goals:
Balance, balance, balance

Don’t break the bank

Good in medium to large rooms

OK for critical listening but has to project well for walking around —

” This is the reason why midrange is at ear level for seated listening, this way the tweeter is up high enough to be appreciated for every day activity. Measured for seated posibion, ears for final tweeks.”

Clean vocals, clean vocals, clean vocals

Good with most types of music

Bi ampable for the purpose of marketability, possible bi amping

As attractive as time permits since I’m not smart enough to make a living at it

Driver Selection:
Dayton Audio RS225P-4 8″ Reference Paper Woofer 4 Ohm

295-377

Dayton Audio RS150-8 6″ Reference Woofer

295-354

Peerless DA25BG08-06 1″ Aluminum Dome Tweeter 6 Ohm

264-1460

Enclosure Design:
Separate 1 f^3 ported chamber tuned @ 49 HZ

Separate sealed chamber @ .1 f^3
Horizontal bracing minumum 5″

Enclosure Assembly:
MDF with a mixture of poly and later cotton for damping

3″ pvc for ports

Tnuts for woofers

Crossover Design:
3 way

4th order low pass @ 310

3rd order bandpass @ 310 & 1500 with countour filter

2nd order high pass @ 1500

2.75 DB attenuation on tweeter

Tips & Tricks:
No real tricks.

Just sound bracing, separate chambers, contour filter for slight tilt — measure, listen, measure, listen.
Adjust where required/desired

Conclusion:
The speaker ended up the best sound I think I could summon from the drivers.

The speakers sound very good, my reference is Paradigm Studio 5 version 6 with much better vocal presentation.

The response curve is very flat with exception of an intentionally upward tilted curve toward the bassline — total of about 4DB at the bottom end

The speaker is very good with most music and even plays ok with rock although some comes across a little harsh @ seated lever

About the Designer:
By trade a UNIX specialist but I’ve always been passionate about music reproduction (audiofool) and always been a DIY guy. Marry these attributes and you get a speaker builder/designer.

I’ve build before but am going to build till I get the perfect sound (just kidding, no such thing.) But I’ll keep trying for perfect sounds for the right applications.

This is the most detail I’ve put into a build thus far and hope to only get better with time.

Project Parts List:

Designer:
Troystg

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
A cheap versatile garage radio for the neighbor.

Design Goals:
Decent sound, low price and somewhat portable.

Driver Selection:
Close out plate speaker from waaay back. Poly cones and plastic grills means they should last in the garage.

Enclosure Design:
Half inch plywood for everything except the front panel. A 1x6x24 inch piece of Poplar was uses just because.

Enclosure Assembly:
Glue, air nails and butt joints.

Crossover Design:
6db/oct from the factory on the plate speakers.

Conclusion:
For a garage box it came out pretty well. I would have painted or veneered it for dust purposes but he liked the black carpet.

About the Designer:
Long time garage tinkerer and all around hack.

Project Parts List:

Designer:
Barleyman

Project Category:
Home Theater

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
Design, build, and install a small home Theatre room. With the emphasis on small. The room is only 11 X 11, and needs to be used for a quest room if needed. ie air mattress. Note the small homemade A/V rack.

Design Goals:
Simple low cost, but good sounding Home Theatre. But with minimal clutter.

Driver Selection:
Pyle PDMW6, 292- 202, 6 1/2 midrange / woofer

Dayton Audio, 275-045, 1 inch metal dome tweeter

Enclosure Design:
Wall Mount – Left and Right

Center channel is a 18 X 11 X 4 homemade sealed box, using 1 X 4 pine lumber and 1 X 10 pine face. aprox. 0.4 cf.

Enclosure Assembly:
17 inch X 7 inch pine stock. The width was chosen to allow the mounting screws to secure to the wall studs. The back side was primed with foam skid cloth to help seal the unit to the wall.

Crossover Design:
Simple 2nd order Butterworth @ 3000 hz. I chose that point because most musical instruments and voice drop off at 2500 – 3000 hz. I did not want to crossover blow that range. That way the main drive handles 80 % of the sound.

Tips & Tricks:
It always takes longer than you think. Change is good.

I sanded and primed the wood stock with poly before any work was started. This helps with the cutting. I routed the speaker cut-outs before cutting the wood down to the final size. The wall cut-outs were minimized, to allow better installation. a finish coat of poly was added just before installation. The cross-over design was bare minimal. I do not believe in access sound manipulation.

Conclusion:
Great sound for a small in-expensive project. Again the goal was to minimize space, which was the reason for wall mounted speakers. The walls add to the bass and the sound may be a bit bright, because of the tweeter selection, but that is what I like. There is a Sub Woofer on the backside corner for real Theatre performance, or if you need the added bass for normal audio listening.

About the Designer:
I was going to build three of the box speakers, and hang them from the wall. but decided this looked terrible. I had installed this wall design about 8 years ago in another house and the kids ( college ) loved the sound. Plus the wall design adds a little bass to speakers that are lacking a bit on the low end. The sound is good and I use it for regular radio and CD listening all the time. The room could be converted from the A/V use to a regular bedroom in seconds. Leave the wall speakers.

Just remember that projects take time and you just need to suck it up and finish them. Mine appears done for now.

Please note – this was a attic room and there was access to the kick wall from behind for the installation. Also there is ethernet for the TV, along with an outdoor antenna jack for the receiver. The A/V rack was made from standard stock ie 1 X 6 and 1 X 8 pine. It was cut and put together in a couple hours, coated in clear poly. I could not find a small A/V rack, and this design just came about. I call it butcher block simple.

Project Parts List:

Designer:
Winston

Project Category:
Home Electronics

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Solar Powered Sound System for an Above Ground Pool

Design Goals:
I wanted a sound system for my pool that was loud enough for me to enjoy the music but not so loud that it annoyed my neighbors. (I like my neighbors.) That meant the speakers had to be close to the pool. But I didn’t want anything connected to AC current anywhere near the pool. It also had to be weather resistant and not likely to be damaged by a flying beach ball or other pool toy. It had to have bluetooth so I can control it from my phone and FM radio – just because.

Driver Selection:
I chose the TIC GS-10 (302-127 ) omnidirectional speakers because they could be mounted on the fence around the pool and they are weather resistant. After first testing, I found the sound needed more oomph – more bass – at lower volumes than these speakers provide So I added a pair of Dayton Audio DAEX32EP-4 Thruster 40W Exciters (295-230) glued to the steel wall of the above ground pool. The steel and the water dampen much of the high frequency energy of these speakers but the low frequency comes through nicely and can be balanced with just a volume adjustment. AND you can hear the music under water!

Enclosure Design:
I know you mean speaker enclosure, but for this project one important element was a waterproof enclosure for the electronic components. For this I chose an Igloo Cool Cube. The main compartment holds the components while the top flap gives you access to the controls.

Enclosure Assembly:
I drilled connections for the speakers and the power input through the body of the cooler and sealed them with silicone sealant. Then I cut an opening between the lid flap and the cooler for the 12 VDC Bluetooth FM Radio MP3 Audio Preamp Board (320-348) and the power switch. I added a Pyle 4 channel Marine amp (# n/a), the batteries, screwed the solar regulator to the inside wall of the cooler and wired her up.

Crossover Design:
N/A

Tips & Tricks:
The Pyle amp is just slightly too large with the connectors attached. Use a hot hair dryer or heat gun on the lid to slightly warp the plastic to make room and still be sure it closes tightly.

After drilling the holes through the cooler body seal around the sides inside the hole to keep moisture from collecting inside the cooler wall.

If you’re not in danger of getting it wet, crack the cooler lid and let the heat escape.

Make sure you have a place to mount the solar panel that faces SW and is out of the way of pool activity.

Get a solar regulator with a USB port and you can keep your phone/mp3 player/etc charged along with the system.

Conclusion:
Is it audiophile quality? No. But the sound is great for having fun in the pool. I wish the TIC speakers had a little more oomph, but weather durability is important to this system and I’m willing to give a little. I am extremely happy with how the Exciters have made up the difference and round out the sound. The Bluetooth pre-amp works great. It locks up quickly and has great range. FM recpetion is very good as well. I have not tried the USB or card portsThe system lives under the pool deck and I can control everything from my phone (in a baggie) without getting out of the water.

With 21Ah of battery life, the system works all day and into the night. Only time will tell how durable the system is out in the weather, but I am very happy with the system so far. It fulfills my needs for good quality sound and no one is in danger of electrocution.

About the Designer:
Dave is a location sound mixer for Film and TV production. He has been tinkering with audio since he was a wee lad. While he has built many rigs for recording sound, this is his first home sound (playback) project. Parts Express has been a life saver in helping me build rigs to record sound in all sorts of tough environments and unusual situations. I was glad to do this one just for fun.

Project Parts List:

###-### Pyle 4 channel Marine Amp
Speaker wire, electrical wire, switches, connectors, etc. from Parts Express. (too many part #s to look up)
Igloo Cool Cube Cooler
Solar Panel
Solar Regulator
3 x 12v7Ah sealed lead acid batteries

Designer:
DonaldMIDI

Project Category:
Amplifiers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
Cabinet for Footnote 5-watt amplifier with built in battery case.

Design Goals:
Cabinet to match speaker enclosures already built.

Enclosure Design:
3/4 particle board with routed edges. Covered with speaker cabinet carpet. Corners protected with Peavey style metal corners. Non-skid feet on bottom. Battery case incorporated into rear enclosure accommodates 6 AA batteries.

Enclosure Assembly:
3/4 particle board mostly glued (4 screws applied prior to routing edges). Speaker carpet spray-glued in place. Amplifier mounted to interior mounting points glued to corners.

Conclusion:
I will use this while camping to practice my bass guitar. I can use headphones or a speaker cabinet (already built). I’ll be able to use a solid-body bass at campground church services even if power is not available (amazing volume for only 5-watts).

About the Designer:
Built my first speaker cabinet at 15 years old. I’ve built many, many cabinets in the 53 years since then…infinite baffle, bass reflex, etc. Used mostly 15″ guitar speakers, but several were with 12″ triaxials for stereo systems.

Project Parts List:

Designer:
Chrome

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
This is a 2x50W portable speaker with outputs for alternative external speakers. It includes a rechargeable battery pack, bluetooth connectivity and enough “umph” to adequately drive large speakers cabinets. The total parts list is roughly $150 plus approximately 5-6 hours of labor.

Design Goals:
I wanted to build a portable speaker system that was reasonably small, durable, and put out good/clean sound. I was hoping for a “military” style appearance with the option to flip a switch, routing the amplifier output to larger external speakers. I’ll be using this to bench-test various speaker cabinets.

Driver Selection:
I used 2 x Dayton Audio PC83-4 3″ Full-Range Poly Cone Driver – 295-154. The airspace needed for these matched nicely with enclosure I had purchased.

Enclosure Design:
I originally wanted to use an old 50cal ammo can I had in the garage. Unfortunately, the metal housing with drastically reduce the bluetooth range so I opted for a plastic version. I was able to maintain the “military” style and good bluetooth range. The plastic ammo can was $10 or so, at a local outdoor store.

Enclosure Assembly:
This is a store bought container, no assembly necessary.

Crossover Design:
No crossover needed, these are full ranger drivers.

Tips & Tricks:
Measure twice and cut once.

Take your time and enjoy the building process.

Bench test your equipment before assembly.

Conclusion:
I was very happy with the sound from these drivers. I was shocked at how clean they sound and the box provides a reasonable amount of bass. I was initially concerned that the “external” speaker output would be lacking or have some crosstalk but quickly discovered I had nothing to worry about. I connected an old pair of AR-11’s to this little amp to test the external speaker function and it worked great. While running on battery power, this box was able to drive my my AR’s with no problem at all.

About the Designer:
I have been working with electronics and RF systems for quite a few years. Although I’ve done a few speaker repairs, this is my first attempt at building a speaker/amp and hope to do many more in the future.

Project Parts List:

Designer:
VC

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
Open Baffle design using the Visaton Fullrange FR13

Design Goals:
To obtain a great sounding speaker under $100.00

Driver Selection:
Visaton FR13 PE Part number 292-518

Enclosure Design:
3/4 inch board measures 11″H x 12″W

Enclosure Assembly:
Open Back

Crossover Design:
2mH 18g steel Laminate

Dayton 10 ohm resistor

3.3uF Dayton Caps

Conclusion:
Sweet sounding fullrange drivers on a budget

About the Designer:
Been building speakers since 2001

Project Parts List:

Designer:
Jeff Greenlee

Project Category:
Loudspeakers/Cabinets

Project Level:
Beginner

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Schematic:
new_speaker_schematic_718

Project Description:
Wanted to build a better set of speakers than the ones I built in high school that I still use today, using solid Walnut just like those (no there is no resonance) to make them a thing of beauty & detailed sound, cost was no object nor was weight a consideration, nobody is going to try & steal them. The final set of speakers I am going to build probably.

Design Goals:
Big, bad, beautiful & superior sounding with no subwoofer required, enough said.

Driver Selection:
2) Morel ST 728s #86-277-090 2)Morel CAT 308s #297-082 4)Eminence Alpha 4-8s #290-4012 2) Dayton (made by Eminence) ST-210-8 8″ series II woofers #295-100 2) Dayton (made by Eminence) ST-385-8 15″ Series II woofers #295-130

Enclosure Design:
15/16″ thick solid walnut cabinets & backs, mitered corner joints with glued & screwed bracing throughout, backs have 1/4″ 3 ply birch laminated to them. 3/4″ solid walnut front baffles with 6 ply 3/8″ birch plywood laminated to them for strength for a 1-1/8″ thickness. 3 port design with baffle separating woofer compartments. 4 Eminence ISO-5 5″ mid range isolation enclosures used. Cabinet dimensions are 28.5″ high x 17.5″ wide x 14.75″ deep. 1″ thick foam glued to insides of cabinet for sound absorption. Black PVC for ports with flanges on the inside for a clean look. Offset terminal board of walnut for beauty. Speaker grill cloth frame made of 3/8″ industrial fiberglass.

Enclosure Assembly:
2 pieces of 7 to 8″ wide 15/16″ thick walnut laminated to get the required 14.75″ width, mitered & braced. Backs & fronts glued into cabinet channel along with glued & screwed bracing from the inside. All speaker cavities routed for flush flanges. Modified cooling fan guards were used for the tweeter guards

Crossover Design:
All 2nd order except for the mid ranges which use a narrow band first order, using TRW, Epos & Rifa polypropylene metal film capacitors, 14 ga. hand wound coils for the woofers. 200 watt 4 ohm L pad for tweeters. (8 ohm 100w stereo L pads in parallel). -6db switchable L pads for the mids & 8″ woofer. Hand wired circuit boards made of fiberglass.

Conclusion:
A very involved & long project that turned out better than expected. I did not hurry on this project that took 4 months to complete, attention to detail was given.

About the Designer:
Built my first set of speakers in high school in 1975, I still have them today & use them. Have built 7 sets of solid walnut speakers over the years because I love to beauty of the wood. There is no resonance when built right. Instrument tech/electronics tech is my job, Audio & music is my passion. I don’t own any manufactured speakers, be they Pro audio or otherwise.
Project Parts List:

Designer:
TomZ

Project Category:
Tower Speakers

Project Level:
Beginner

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
This speaker set is a “Micro-Tower” design… full range sound in a very small size.

Design Goals:
Like many longtime speaker builders, not all of the speakers I build have an immediate purpose for their existence. Since my house is literally full of speaker pairs, I often just build them because I love to do so. These speakers, however, have a specific reason for their creation, they were designed for my niece, who’s name is Summer Lace. College life is behind her, and she is living on her own in an apartment in New York State. Upon visiting her last year, my wife and I noticed that she did not have a real sound system. She indicated that she would like a set of speakers from her uncle, and the result of some thinking and pondering yielded these… the ‘Summer Winds’.

Driver Selection:
These speakers would need to be very small due to space constraints in her apartment. This limited my driver choices to those around 3” and under in order to keep the total cabinet width reasonably narrow, as well as for better off-axis sound dispersion.

Having used the Dayton ND65 drivers in several previous projects, I chose them once again for their small size and fairly clean output. They have a long throw and copper in the motor which allows them to reproduce full-range sound at decent volume levels. The tweeter needed to be small enough to be placed very near the top of the enclosure, so the ND16 press-fit tweeter was one of few that would work, plus it sounds very nice, having a wonderful ‘sparkle’ to it. These drivers would have made a decent sounding speaker on their own, but would have needed a boost in the bass department for sure in order to yield decent output levels.

Enclosure Design:
I really like the narrow tower format because when designed small enough, they are not much more intrusive than a set of small speakers on a traditional stand. I also like speakers with curves, it’s just my preference… but sometimes it’s also the only way to get a certain driver to fit.

I originally considered using the ND105 driver as a woofer in this design, but when I realized that I could get deeper, louder bass from the Peerless 5.25” woofer in about the same space, I decided to try and see if I could implement it somehow. The result ended up being facing the driver in a down-firing configuration, and flaring the sides of the cabinet larger towards the bottom in order to fit the width of the driver. The volume for the Peerless sub is about 13.6 liters, and is vented with a 1.59” (1.5” black ABS at a home improvement store) by 7” port. The upper volume for the two ND65 drivers is 3.1 liters.

This cabinet is only 29.5” tall on it’s brass spikes, which places the tweeter terribly low. I didn’t think my niece would necessarily feel like sitting on the floor just to hear her music, so I decided to curve the front of the speaker up to aid in distributing the sound into the room a bit better.

The veneer is striped ebony and the cabinet is finished with several coats of rub-on polyurethane. The outrigger legs are solid redwood and painted with black and clear lacquer; combined with the brass spikes, they give the bottom-mounted woofer a bit of room to breathe.

Enclosure Assembly:
Curvy speakers have an advantage over standard flat panel speakers, in that the curves can often allow for less material thickness per a given square footage. 3/4” MDF is the standard thickness for most speakers, but these speakers have panels that are much thinner… 1/2” thick on the top, 3/8” thick on the sides, 1/2” on the back, and 1/4” on the front baffle. For everything but the back and bottom panels, I use multiple layers of 1/8” HDF (high density fiberboard.) In fact, the only 3/4” material in the entire speaker is the bottom panel… mostly because I needed something substantive and ‘square’ to attach the ‘bones’ of this speaker to. The knuckle test tells no lies — rap on any panel of this speaker and it’s solid all around. Consider a barrel made with thin sheet metal… it’s very strong because of the curve of the sides… and resists bending and flexing because curved material can resist those forces much better than a flat panel of the same thickness. Imagine a square box made of the same thickness of sheet metal as a metal barrel of the same cubic volume… it would flex far too much to be of much use. The curves on the front and sides of the ‘Summer Winds’ allow for thinner material used in multiples to make up for the lack of thickness, and it also looks cool!

I needed to construct several jigs to pre-bend and glue up the multiple layers of 1/8” HDF that comprise this cabinet. There are several inside braces that help ‘hold’ the thinner layers of material in place until the glue dried. Once the entire cabinet is glued up, it is a rigid — but light — unit.

I used Tightbond II wood glue to adhere the thin 1/8” panels to each other, and Gorilla glue or PL Premium construction adhesive to glue the panels to the speaker framework.

Speaking of framework, this speaker has several internal braces that aid in rigidity, as well as create the curve which the side panels would eventually glue to. I drilled as many holes into those braces as I could to make things lighter, and allow for open airflow within the cabinet. Those braces are mostly made of 1/2” MDF with a few pieces of 1/4” MDF as well.

Since I had to spend so much time making custom jigs to build these speakers, I decided to get a little more return on my time investment and build 3 pairs at the same time, which is why there are multiple speaker carcasses in several of the pictures.

Crossover Design:
I went for a minimalist design for this speaker. Being a three-way speaker it needed a fair number of crosser bits already… add to that the low crossover point of 150 Hz. from the woofer to mid drivers, and you already have a few fairly costly, and decent sized components to deal with in a very small internal volume. With a good amount of fiddling, I was able to get a fairly flat response with only 11 components in the crossover. The crossover point between the midwoofers and tweeter is 5,000 Hz, and all slopes are second order LR electrical. I have the tweeter just a bit hotter than I normally would use in most of my own speakers; this is because I believe these will not really be used as “sit down and listen” speakers, but will rather be listened to while moving about the apartment, often not right in front of the speakers themselves.

I’m glad I made lots of holes in the framework of these speakers… I had to use one of them to stick a particularly large 100uF cap as it didn’t fit on the crossover board.

Tips & Tricks:
In order to maintain consistency, I made one ‘perfect’ master template of the front and back pieces, which I reproduced with a router and trim bit for nearly perfect copies.

The top and front panels were pre-bent as individual glue-ups before attaching them to the frame of the speaker.

Being so small means that everything must be thought of beforehand. There is really no room in this cabinet to do anything but install drivers, and a minimal crossover board in the bottom woofer opening.

Since I used hardwood for the bottom outriggers, I was able to drill and tap them with a standard metal tap and die set to attach the speaker spikes right into the hardwood with no metal insert. Since the spikes are screwed fully into the outriggers, there is no concern with the threads giving out.

The particular binding post I used was chosen for it’s shallow mounting characteristics. The vent tube for the port is very close to the rear of the enclosure, and would have created interference issues with a standard terminal cup.

I thought about how I would mount the crossover in the early stages of the cabinet design. I glued a small piece of maple to the inner framework of the speaker which would be assessable from the bottom subwoofer opening. I used thin plywood as crossover mounting boards and pre-drilled holes to mount those boards. That way, when I finished the crossover, I knew it would mount right to the inner crossover mounting point with no issues as long as the components were not much bigger than the outer dimensions of the crossover board.

Conclusion:
This design is now honestly one of my favorites. I love all the curves, and I get a real kick out of hearing full-range sound out of a speaker cabinet that is so tiny at 4.5” wide and only 29.5” tall. I didn’t anticipate that this design would play very loudly, but I’ve actually tested this system out on a few movies and they can keep up with the audio of an action movie in a medium sized room just fine. The vented Peerless subwoofer drivers really produce ample bass; they model very closely to the venerable Tang Band W5-1138 subwoofer which I considered using as well. The bass output of the Peerless sub is augmented by their downward firing configuration and close proximity to the floor (less than 2”.)

These speakers measure reasonably flat down to 37 Hz, a surprising frequency range for something so tiny. For normal listening levels, a subwoofer would not be required.

About the Designer:
I’ve been tinkering with and building speakers since I was a teenager, though I admit… most of those early speakers didn’t sound very nice. After I found Parts Express, and the Tech Talk website, I was able to get answers to many of my questions from the many generous folks on the forum. That help, combined with a lot of reading, practice, and some tenacity to follow my speaker building aspirations have helped me to finally be able to create speakers that look and sound like I’ve always wanted them to.

Project Parts List:

Designer:
B-52 Bombers

Project Category:
Home Theater

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Pair of horn loaded speakers.

Design Goals:
To build a speaker that could be good for home audio use and professional use. I wanted to use horns because those allow greater SPL. The trick was to get the horns to sound good I had to select the correct drivers. The drivers needed to get loud if necessary but also have clean sound at lower levels. For the base cabinet, I wanted to try to create something that utilized just a base cabinet (almost like a subwoofer). I used a 15″ EV mid-woofer with dual 9.5″ deep ports to offer a good bass response.

Driver Selection:
B-52 Comp-4-MX

PRV Audio D230Ti-Nd-B

EV SH 15-2

Conclusion:
This was my first entry into the MidWest AudioFest 2018.

About the Designer:
I’m 14yrs old and just started speaker building and designing. I started building when I was 12-13yrs after attending a flea market sale and picked up 2 pairs of bookshelf speakers. Then I tore them apart and built a tower speaker from them. This led me to explore and discover the audio industry. From there I entered into the Midwest Audio Fest this year and met many wonderful people. I am currently working on a transmission line speaker.

Project Parts List:

Designer:
JSH Designs

Project Category:
Freestyle Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
Over $1,000

Project Description:
Greetings:

Several years I introduced a project called PVC Extreme. The project entailed using schedule 40 PVC pipe in an MTM design as an exploration in new and innovative home speaker design. The results were fantastic, so much so that I added rear speakers of a similar design and concept for a full surround system. The realism and overall encompassing sound is amazing, but left me with a burning desire to explore new and innovative speaker designs. In short, I’ve been stricken by the DIY audio bug.

This disease, which so many of us seem to suffer from, lead me to the 2017 NYC audio show last November. Here I encountered like-minded, borderline psychotic audiophiles, searching for the latest in design and sound quality. I was determined to prove to myself that PVC Extreme could match up with the “big boys” in the speaker game. However, instead of reassuring myself that PVC was the future of speaker design, I walked out feeling that there are a lot of really good speaker systems out there. I had not done a deep enough dive here. What I now wanted was to design and build a set “end game” speakers. Not just a series of boxes with top quality components and off the shelf design, but something unique, with top level sound quality, and most importantly, something that relied on creativity rather than wood working skills. There is only so much that I can do in my basement on weekends.

At the show, I came across a set of open baffle speakers. I had some familiarity with the theory, but had never heard them before. For whatever reason, most manufacturers have been reluctant to develop open baffle product lines in the past. Perhaps it’s that the previous designs have been rather utilitarian with limited aesthetic appeal. After all, the back ends of all the components are exposed, wires and all. They tend to look somewhat unfinished. Lack of commercially available open baffle designs may just have to do with marketability, as the open baffle sound is incredible. It’s clear, open, tight, and very realistic. The overall effect is one of the closest to a live performance that I have heard. The sound comes from everywhere, just like a live performance. The challenge is to make the speakers look as awesome as the sound.

Design Goals:
As such, let me introduce Kang and Kodos – Alien Open Baffle Speakers.

They stand about 5 ft. tall and sit on 24” x 28” bases with casters on the bottom so they can easily be moved. They’re pretty heavy, each weighing about 120 lbs. They are constructed from 1” red birch plywood with 3 to 4 coats of wood dye or stain depending on the color. All the wood is sealed with 4 coats of water based poly urethane and sanded and buffed to a medium gloss finish.

The speakers and cross over network were sourced through the company Pure Audio Project, though most of the components can be found on the Parts Express web site. The woofers are 15” Eminence OB-A15 Neo which is nearly identical to PE’s Eminence Kappalite 3015LF Neo 15″ Speaker Driver. The compression horn tweeter / midrange driver uses an extended Polymer 1.4” compression tweeter, which is very close to PE’s Faital Pro HF146R 1.4″ Neodymium Compression Horn Driver or a Beyma CD14ND. The crosses over components are from the German company Mundorf. Lastly the gorgeous wood horn is by craftsmen in Spain. This was one of the primary reasons that I sourced the components thru PAP.

The design and build took roughly 6 months, mainly working on week ends. Fortunately New England Winters are long so I didn’t feel too bad about spending my time working inside .

Now for the sound. Truly amazing and well beyond expectation. The first thing that comes to mind is how much these speakers create the illusion of a live performance. I go to a number of live jazz clubs and theaters in my area and the sound is always much different than reproduced sound. Obviously there are many components that contribute to why recorded music doesn’t sound like the real thing, but I’ve always felt that the right speakers make up 60% of the end result. 25% can be attributed to the recording and engineers, and the rest to the electronics. These speakers get closer to the “live” goal than nearly every other speaker I’ve previously heard. There is an airiness and openness that doesn’t exist with most other speakers. The dynamic range is quite expansive as is the soundstage. The compression horns allow the brass, winds, piano, and vocals to break out easily from the typical wall of sound. The (4) 15” woofers are very tight down to around 30 or 40 hz. Bass is incredibly tight with no boomy or muddy sound that may speakers have. The sound never feels as if it is coming from 2 points, but from all over. There is no traditional “box“ speaker sound. Like I said, it sounds like a live performance.

Products Used:
Drivers are very similar to these PE products

Eminence Kappalite 3015LF Neo 15″ Speaker Driver
Brand: Eminence Speaker
Model: Kappalite 3015LF
Part # 290-598
https://www.parts-express.com/eminence-kappalite-3015lf-neo-15-speaker-driver–290-598

Faital Pro HF146R 1.4″ Neodymium Compression Horn Driver 8 Ohm 4-Bolt
Brand: FaitalPRO
Model: HF146
Part # 294-1052
https://www.parts-express.com/faital-pro-hf146r-14-neodymium-compression-horn-driver-8-ohm-4-bolt–294-1052
Conclusion:
Overall I think I achieved what I was looking to do, create an “end game” set of speakers. Unfortunately, I’m still afflicted by the DIY speaker building disease. I’m currently working on a set of surround speakers and subwoofer to pair with Kang and Kodos, for home theater use. I’ll be sure to share this next chapter.

About the Designer:
I’ve been a designer and builder of sorts all my life (licensed architect and general contractor by trade). I’ve designed and built works of art, furniture, motorcycles, homes, and large scale mixed use buildings. I’m a big believer in having form be equal to function.

Project Parts List:

Designer:
MASC 2

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$500 – $1,000

Project Description:
Prototype loudspeaker, for future sale through internet

Design Goals:
Speaker with both aesthetic and acoustic presence.

Practically without resonances due to an extremely elaborate cabinet.

The walls have three layers of solid material, and three types of internal damping.

Driver Selection:
Part # 300-641

Enclosure Design:
Reflex

Enclosure Assembly:
cabinet in double 9mm mdf, plus oak veneer.

7 coats of lacquer applied by hand, sealing of all internal surfaces, and treatment against moisture.

two inerter reinforcement rings, with all rounded edges to avoid turbulence.

As well as the front of the speaker, rounded.

This created a challenge for natural wood veneer

Crossover Design:
the provided, eliminating the circuit, welding point to point, in silver.

Conclusion:
A loudspeaker was achieved, very solid, and due to the careful design of the components, the sound in without fear of appearing exaggerated; almost perfect.

Solid bass sounds, without dominating the whole, a medium range, absolutely natural.

The range of treble, due to the rounded front, are very natural and without diffraction.

The only problem, could be its weight, almost 14 kgm each, but it helps enormously to a clean sound.

About the Designer:
With a sporadic experience in loudspeaker design and construction, over 30 years, and because I did not find a distributor in Mexico, let alone a speaker manufacturer, I had been frustrated.

Now with Parts Express, I think I will dedicate myself to making this and other models.

Project Parts List:

Designer:
Bill S. (4thtry on PETT)

Project Category:
Tower Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
This is a small tower speaker using the new Dayton CX150-8 coaxial mid/tweeter and the reference series Dayton RS270P-8 10″ woofer. It features an artfully shaped curved cabinet combined with solid walnut upper and lower baffle boards.

Design Goals:
My goal was to design the very best sounding coaxial type speaker that I could with plans to enter it in the InDIYana 2018 “Keeping up with the Jones” competition (held in Fort Wayne, IN, April, 2018). Contest rules limited the woofer size to 10″ and the total internal cabinet volume to 2 cubic feet. Later on, I was also planning to enter this speaker in the MWAF Speaker Design Competition, so I gave the cabinet an unusual shape to create added interest during the show.

Driver Selection:
The coaxial driver selection process was very easy. During last year’s MWAF Speaker Design Competition, my name was the first one pulled from the door prize hat. The next thing I knew, I had a free pair of the new Dayton CX150-8 coaxial drivers in my hands.

Woofer selection was just as easy. The next day, during the tent sale, I found a pair of Dayton reference series RS270P-8 woofers at substantial discount. Parts Express ran the T/S parameters for me, which showed that this driver would work out just fine in a 1.75 cu. ft. box tuned to about 30Hz or so. I was all set!

Enclosure Design:
The basic cabinet is constructed of 3/4″ thick particle board material throughout. The upper and lower baffle boards are a 1.5 inch thick composite of 3/4″ particle board and 3/4″ solid walnut.

I put the coaxial driver in an upper, sealed 0.25 cu. ft chamber and stuffed it with Acousta-Stuf and fiberglass at a rate of approximately 0.75 lbs per cubic foot. I put the woofer in the lower 1.7 cu. ft. volume and tuned it to 30Hz. The port is a rectangular affair with an ID of 1.85″ x 3″ and a length of 7.75″. The woofer cabinet is lined internally with 1/2″ fiberglass throughout and stuffed at the upper end with 4 ounces of poly-fill

I mass loaded all internal mid-range and woofer cabinet walls every 5 to 6 inches with heavy, 1/4″ thick steel bar stock. Each piece of bar stock measures 1/4″ x 1.5″ x 7″ and floats individually in a thick 1/2″ layer of 100% silicone rubber cement. This results is a very dull knuckle rap test on all sides and back.

Enclosure Assembly:
The curved side panel is a composite of 6 layers of 1/8″ thick tempered HDF material, glued together with yellow wood glue. I spent a full week building a special fixture to clamp this curved side panel in place. I used approximately 3/4 gallon of yellow wood glue! A substantial portion of this glue was sacrificial and dripped away during the clamping process! I put down several long strips of wax paper along the lower edges to catch the glue before it hit the floor!!

I finished the cabinets with oil based primer and then several coats of “sand” colored high gloss enamel. I finished the solid wood baffles with Danish oil to darken the walnut. After the Danish oil had dried completely, I finished the walnut with 10 to 15 light coats of semi-gloss lacquer.

Crossover Design:
After finishing the cabinet and mounting all drivers, I used OmniMic and DATS V2 to create a complete set of on-axis FRD and ZMA files to develop the crossover. I used the blender software package to merge diffraction adjusted near and far field woofer and mid-range measurements.

But I made one small mistake that had a huge impact on the design. My woofer is located 7.5 inches from the floor and I failed to properly take into account the floor boundary reinforcement effect. As a result, when we played the speakers at InDIYana, they sounded very fat and heavy in the mid-bass (a very dark tonal balance).

So it was back to the drawing board. After several additional “mistakes” I came up with a “re-design” that sounded fairly good. I knocked out the phase plugs on the RS270P-8’s and replaced them with dust caps. I glued a small 30 ounce steel washer to the back side of the dust cap to increase the mass of the cone and reduce the woofer output by about 2-3dB. Then I glued a small enclosure filled with poly-fill to the back of the woofer magnets to seal off the vented pole piece and “re-tune” the voice coil cavity to eliminate an unexpected 150Hz resonance created by my dust cap modification!

I set the tweeter to mid crossover at 4kHz, 12dB per octave electrical. I set the mid to woofer crossover at 400Hz, 12dB per octave electrical. Impedance dips to 4.5 ohms at 500Hz but the phase angle is good.. Overall sensitivity is approximately 87dB/2.83V/1 meter.

Tips & Tricks:
Attached picture caption listing:

PIC: CAPTION:

_DS52918: Completed speaker.

_DS49932: I made a full-scale template to cut the curved baffle boards with a jig-saw.

_DS50278: Glue up of the box shell, showing the angled upper & lower cabinet partition.

_DS50454: Glue oozes out as the custom clamping fixture applies pressure.

_DS50524: Six layers of curved 1/8″ HDF are fully set in place after removal of fixture.

_DS52221: A look inside the woofer cutout showing xover and input cup.

_DS52486: Upper walnut baffle finished and ready for attachment via pocket screws.

Conclusion:
In terms of sound quality, these speakers are very polite and easy to listen to. The overall tonal balance is very good from top to bottom, perhaps just a little bit heavy below 100hz or so. This speaker applies the full 6dB of baffle step compensation, so it should be located well away from the rear and side walls for the best overall sound quality.

About the Designer:
I have been building speakers and amplifiers, as a hobby, since the mid 1970’s. In my spare time, I enjoy football, fishing, camping, landscape photography, building amplifiers, and, of course, building speakers. I also enjoy attending the many DIY events in the Midwest to see what other speaker builders are up to. I do not have a formal degree in electronics or engineering. Instead, most of my skills have come from reading detailed construction threads posted on the PETT forum.

Project Parts List:

Designer:
Bill S. (4thtry on PETT)

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
This is a super thin, 3 way loudspeaker with excellent imaging, very flat frequency response in the mid-range, and a very broad and uniform horizontal and vertical polar response pattern. It uses the full 6dB of baffle step compensation and should be placed on a 24″ high speaker stand and be located well away from the rear and side walls of a moderate to large sized listening room.

Design Goals:
My goal was to design the best sounding speaker that I could without exceeding $200 for all drivers. I wanted it to be capable of at least 95dB SPL at 1 meter with good low frequency extension to 35Hz. Stable imaging and 3D sound-staging were extremely important. The speaker must also have good high frequency extension, clarity, or “air” without harshness in the mid to upper treble region. Finally, the speaker must have a very neutral tonal balance from the mid bass up through the lower treble region (350 to 4500Hz).

Driver Selection:
Tweeter: I selected the Dayton Air Motion Transformer AMT Mini-8 to keep driver cost down and to meet my goal of good clarity and “air” without harshness. The crossover point, however, must be kept very high when using this particular driver.

Mid-range: I selected the Tectonic Elements TEBM46C20N-4B 75mm Balanced Mode Radiator (BMR) to keep driver cost down and to meet my goal of a very neutral tonal balance from 350-4500Hz. I have used this driver before and find that it has a very flat and smooth sounding response throughout the mid-range and lower treble region. It seemed like the perfect match to the AMT Mini-8, which needed a very high crossover point. In addition, this driver has a very broad and uniform horizontal polar response that is very similar to the tweeter. With close driver placement, I felt that I should be able to obtain excellent horizontal & vertical polar response.

Woofer: I selected the Dayton LW150-4 low profile 6” woofer because the cost was low and I needed a shallow driver for side mounting on a thin cabinet. Based on my experience, I have found that a very thin baffle is needed to meet my design goal of excellent 3D sound-stage imaging. The LW150-4 fits my design criteria perfectly because it is only 1.5” deep and can be tuned quite low in a very small cabinet.

Enclosure Design:
Internal cabinet volume is approximately 10 liters. External dimensions are 19” H x 3.5” W x 20.75” D. Material is 3/4” laminated particle board shelving throughout. I created the port by simply gluing in a 15.5” x 2” partition, 2.75” forward from the rear of the cabinet, leaving a 2” opening at the bottom for the port exit. The port therefore has an inside diameter of 2” x 2” and is 16.5” long (Fb: 40Hz). I lined the cabinet internally with 1/4” thick dacron. I used several small 1.5”x 2” side to side braces to stiffen the side walls. I supported the speaker on the bottom with a 6×9″ base board.

I located the side mounted woofer 11.5” from the top and 7.5″ back from the front of the cabinet. This places the woofer at the golden mean ratio (1.62 to 1) which helps to spread out internal cabinet cancellation and reinforcement modes.

I gave the mid-range a small, sealed sub enclosure that measures 2”x 2”x4” internally and constructed it from 1/4” thick HDF material. I stuffed it with two layers of 1” thick dacron. I located the mid-range cutout 5.75” down from the top of the cabinet, on center. I positioned the tweeter cutout 3” down from the top of the cabinet, also on center.

Enclosure Assembly:
I used miter joints on the two sides and top to create a smooth, hidden top seam. The baffle board is 3.5”x 18.375” and is surface mounted with yellow wood glue. The 2”x 15.5” rear panel is inset into the cabinet’s back and is open on the bottom for the port exit. The sides are 18.5” x 20” and are mitered 45 degrees along the top edges. The top is 20” x 3.5” and is mitered 45 degrees along both of the long, top edges. I used gaffers tape to hold the two sides and top together, filled the miter joint with glue, and then folded & clamped the composite into the shape of a very flat box.

I flush mounted the woofer, mid-range, and tweeter using custom templates and a router bushing set. This keeps the plane of all drivers totally flat with the plane of the baffle and the plane of the side walls. To soften the baffle step, I used a 1/2” round over bit to ease the baffle edges. I used a 1/4” round over bit to ease the top two edges. After finishing and sanding the edges, I painted them with a single rattle can of Hammered Silver (#7213).

I built the crossover externally on a 12″ x 11.5″ piece of 3/4″ laminated particle board, mounted vertically to a 12″ x 3″ base. It is connected to the drivers via 6 individual runs of 16ga OFC cable, bundled inside a 3 foot length of Techflex expandable sleeving. I connected these cables individually to the crossover board using 3 sets of stereo banana jacks. This gave me complete access to all driver terminals at the crossover so that I could easily re-do any botched measurements or flip the phase to examine reverse nulls.

Crossover Design:
After finishing the cabinet and mounting all drivers, I used OmniMic and DATS V2 to create a complete set of on-axis FRD and ZMA files that included baffle step and floor boundary reinforcement gain. Since my “in room” measurements are only quasi-anechoic down to about 400Hz, I applied 1/3rd octave smoothing below this frequency to create files that were very close to quasi-anechoic down to approximately 100Hz. I then loaded these raw FRDs into the XSim software package, set the mod delay offsets, and developed the crossover

I set the tweeter to mid crossover at 4.2kHz, 12dB per octave electrical. I set the mid to woofer crossover at 350Hz, 12dB per octave electrical. XSim is a very easy software package to use, allowing the user to quickly adjust part values and/or swap parts in and out on the fly. In very little time, I had a simulation that measured + or – 0.5dB from 350 to 4500Hz and roughly + or – 2.5dB from 35 to 17000Hz. Impedance dipped to roughly 3 ohms at 125Hz but the phase angle was roughly 0. Any amplifier capable of driving a 4 ohm load should have no problems with this speaker. Overall sensitivity was approximately 85dB/2.83V/1 meter.

Conclusion:
This was a fun project. Flat cabinets, flat drivers, flat mountings, flat crossovers, and a reasonably flat frequency response as well, both on and off axis! All in all, a very good sounding speaker for the price. And I can listen to this speaker system for hours without fatigue. The AMT Mini-8 gives the mid to upper treble region a special clarity, depth, and “air” that blends well with the smooth and very neutral sound of the TE 75mm mid-range.

About the Designer:
I have been building speakers and amplifiers, as a hobby, since the mid 1970’s. In my spare time, I enjoy football, fishing, camping, landscape photography, building amplifiers, and, of course, building speakers. I also enjoy attending the many DIY events in the Midwest to see what other speaker builders are up to. I do not have a formal degree in electronics or engineering. Instead, most of my skills have come from reading detailed construction threads posted on the PETT forum.

Project Parts List:

Designer:
Winston

Project Category:
Home Electronics

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Solar Powered Sound System for an Above Ground Pool

Design Goals:
I wanted a sound system for my pool that was loud enough for me to enjoy the music but not so loud that it annoyed my neighbors. (I like my neighbors.) That meant the speakers had to be close to the pool. But I didn’t want anything connected to AC current anywhere near the pool. It also had to be weather resistant and not likely to be damaged by a flying beach ball or other pool toy. It had to have bluetooth so I can control it from my phone and FM radio – just because.

Driver Selection:
I chose the TIC GS-10 (302-127 ) omnidirectional speakers because they could be mounted on the fence around the pool and they are weather resistant. After first testing, I found the sound needed more oomph – more bass – at lower volumes than these speakers provide So I added a pair of Dayton Audio DAEX32EP-4 Thruster 40W Exciters (295-230) glued to the steel wall of the above ground pool. The steel and the water dampen much of the high frequency energy of these speakers but the low frequency comes through nicely and can be balanced with just a volume adjustment. AND you can hear the music under water!

Enclosure Design:
I know you mean speaker enclosure, but for this project one important element was a waterproof enclosure for the electronic components. For this I chose an Igloo Cool Cube. The main compartment holds the components while the top flap gives you access to the controls.

Enclosure Assembly:
I drilled connections for the speakers and the power input through the body of the cooler and sealed them with silicone sealant. Then I cut an opening between the lid flap and the cooler for the 12 VDC Bluetooth FM Radio MP3 Audio Preamp Board (320-348) and the power switch. I added a Pyle 4 channel Marine amp (# n/a), the batteries, screwed the solar regulator to the inside wall of the cooler and wired her up.

Crossover Design:
N/A

Tips & Tricks:
The Pyle amp is just slightly too large with the connectors attached. Use a hot hair dryer or heat gun on the lid to slightly warp the plastic to make room and still be sure it closes tightly.

After drilling the holes through the cooler body seal around the sides inside the hole to keep moisture from collecting inside the cooler wall.

If you’re not in danger of getting it wet, crack the cooler lid and let the heat escape.

Make sure you have a place to mount the solar panel that faces SW and is out of the way of pool activity.

Get a solar regulator with a USB port and you can keep your phone/mp3 player/etc charged along with the system.

Conclusion:
Is it audiophile quality? No. But the sound is great for having fun in the pool. I wish the TIC speakers had a little more oomph, but weather durability is important to this system and I’m willing to give a little. I am extremely happy with how the Exciters have made up the difference and round out the sound. The Bluetooth pre-amp works great. It locks up quickly and has great range. FM recpetion is very good as well. I have not tried the USB or card portsThe system lives under the pool deck and I can control everything from my phone (in a baggie) without getting out of the water.

With 21Ah of battery life, the system works all day and into the night. Only time will tell how durable the system is out in the weather, but I am very happy with the system so far. It fulfills my needs for good quality sound and no one is in danger of electrocution.

About the Designer:
Dave is a location sound mixer for Film and TV production. He has been tinkering with audio since he was a wee lad. While he has built many rigs for recording sound, this is his first home sound (playback) project. Parts Express has been a life saver in helping me build rigs to record sound in all sorts of tough environments and unusual situations. I was glad to do this one just for fun.

Project Parts List:

###-### Pyle 4 channel Marine Amp
Speaker wire, electrical wire, switches, connectors, etc. from Parts Express. (too many part #s to look up)
Igloo Cool Cube Cooler
Solar Panel
Solar Regulator
3 x 12v7Ah sealed lead acid batteries

Designer:
CBG amp

Project Category:
Amplifiers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
a mobile amp for playing my cigar box guitars

Design Goals:
using recycled materials in the design of CBG’s

Driver Selection:
8″ Celestion speaker

Enclosure Design:
old wine case

Enclosure Assembly:
already build

Conclusion:
add a battery holder to make it mobile

About the Designer:
I enjoy building 3string CBG’s and amps

Project Parts List:

Designer:
nick santorinoes

Project Category:
Bookshelf Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
This was my theme entry into the Indiyana “Keeping up with the Jonses” event. It required a mid woofer with a coaxial mounted tweeter augmented with a woofer or subwoofer. So, basically, a coaxial three-way.

Design Goals:
My goal was to build a full range medium sized speaker with a home-built coaxial driver. I had been eyeballing my wife’s reproduction of a 50’s popcorn machine as a visual inspiration for a speaker build. This seemed like the perfect time to bring my idea to fruition.

Driver Selection:
I started my search by looking for drivers with removable phase plugs. I know from previous experience with my “stink eyes” project that most phase plugs are fairly easy to remove and once removed provides space for the tweeter. I settled on a Dayton rs100p 295-369. Once the phase plug was removed I was able to get a good measurement and search for a tweeter that would fit. That brought me to the Tang Band 1761 264-841. The truth of the matter, that’s just what fit. Once I found my mid and tweeter, I then perused the stash of drivers on my shelf for a woofer that would fill the need both in performance and esthetic. Next I modeled several six to eight inch drivers, but kept coming back to the Tang Band W69 264-837 for its simulated performance as well as its unusual shape.

After choosing my drivers I set forth to combine the mid and tweeter into one unit. This required me to turn an aluminum sleeve on my lathe. I did this so that the combination of sleeve and tweeter would equal the diameter of the phase plug and would physically provide a smooth transition between tweeter and mid.

During initial accoustic measurements, the mid tweeter combination had a large suck out in the upper frequencies. After several attempts to mitigate the suck out, I devised a way to move the tweeter in and out in small increments while taking acoustic measurements. I found that at 0.08″, the previous suck out was reduced to less than two decibels and was now just a narrow dip at about 12.5khz. This required a new sleeve with a step in the rear to hold the tweeter 0.08″ off being fully seated in the driver.

Enclosure Design:
The enclosure is completely made of MDF, and is comprised of three main pieces. The bottom and middle section are both truncated pyramids with differing side angles, while the top could also be considered a truncated pyramid, it is only 1.5″ tall and therefore basically just a cap. I chose to build it in three separate sections for two reasons. The first reason was to give it the rounded edges where sections meet, in order to mimic metal construction, and the second reason was to make my life easier when it came time to paint. The bottom of the lower section measures 11″ x 14″ , the top is 9 3/4″ x 12 3/4″ and the height of just the lower section is 14 1/4″. The bottom of the middle section matches the top of the lower at 9 3/4″ x 12 3/4″, the top is 8 5/8″ x 11 5/8″, and the height of the middle section is 7 1/4″. The top cap is 1 1/2″ tall, again matching up to the dimensions of the piece below. The middle section has an internal truncated pyramid serving as an enclosure for the RS100p, which leaves an overall volume of 26L for the Tang Band w69. The w69 is tuned to approximately 36hz through a pair of 2″ ports 13″ long exiting in the rear.

Enclosure Assembly:
The entire enclosure as stated above, is constructed of 3/4″ MDF, with the exception of the internal mid enclosure, which is made up of 1/2″ MDF. The actual construction was time consuming and a bit tedious due to there being multiple sections that needed to be built, matched up and be connected. All three sections contain threaded inserts and are held together with 10-32 machine screws. The physical construction is straight forward in that the individual pyramids were cut and glued using titebond III. The top cap is composed of two layers of MDF with the center of the lower layer removed, forming a rectangular ring on the bottom. Once all three sections were complete, I bolted them together, got out the old router and and hit the four vertical edges with a 3/4″ round over bit. It was then time to take the cabinets back apart and round over all the horizontal edges using a 3/16th radius. The next step was to glue in the ports, radius the outside edges and fabricate a removable bottom to facilitate final assembly. The cabinets are finished in automotive paint. The steps are as follows: polyester primer, block sand, 2k primer block sand, base color, clear, wet sand, buff and polish.

Crossover Design:
For those of you who only like minimal parts counts in your crossovers, quit reading right now, because this one will give you nightmares or at least shaking your head thinking I’m crazy or don’t have a clue.

Starting with the tweeter, it’s pretty normal, requiring an electrical third order slope to keep it happy, and a notch filter for shaping, possibly due to the unusual application.

The woofer is also pretty standard except I normally wouldn’t use a zobel, but in the case the impedance shoots up fairly early and the compensation kept my inductor sizes down.

The midrange is where things became interesting. Removing the phase plug revealed a large breakup at about 10khz. The fourth order filter along with a zobel, dropped the peak down to an inaudible level. The 15uf cap and 3.3r resistor are there for shaping purposes. Throughout development of the crossover it would not be an exaggeration to say that I have way over 100 hours of listening time in trying different slopes, topologies, and just general adjustments. One other thing of note is that right before MWAF, I tried to improve the crossover, and came up with an alternative design that had the same tonal balance, but provided more detail. The problem was that is became fatiguing after a short time. So back to the original.

Conclusion:
Overall, I would have to say that these are very listenable for long periods of time, with no fatigue. while the drivers used are hardly high end, they do an admirable job working together creating a smooth sound with a good soundstage, and the W69 is surprisingly good in the bass department.

About the Designer:
I am an electrician by trade. I started tinkering with speakers shortly after getting my first real stereo in 8th grade, an MCS setup. I continued to build and tinker, upgrading stereo components and building speakers until my mid twenties, at which point I took a nearly twenty year hiatus before getting back into it full swing.

Project Parts List:

Designer:
Julian Franke

Project Category:
Tower Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
Over $1,000

Project Description:
3-way, Bass Reflex design in an MTMW configuration

Design Goals:
My goal was to design audiophile quality speakers with a contemporary look, a furniture grade finish and “spousal” appeal, while keeping the size to a minimum and maximizing the frequency response.

Driver Selection:
Woofer: DA RS2255-8 8″ (295-356), Qty. one per speaker

Midrange: DA RS125-4 5″ (295-370), Qty. two per speaker

Tweeter: DA DC28FS Shielded Silk Dome (275-075), Qty. One per speaker

Enclosure Design:
The enclosure has parallelogram shape with a baffle angle of 15 degrees. The tweeter and midranges are mounted on the front baffle with the 8″ woofer mounted on the side. The left and right speakers are mirror images of each other. It has a butcher block look design element that carried over from a previous project.

Enclosure Assembly:
The best way to describe the enclosure assembly is a cross between Lincoln Logs and Lego Blocks. Most of the 125 wooden pieces (per speaker) are 3/4″ x 1″ of various lengths with the ends cut at a 15 degree angle. Each piece was glued and clamped in place to form the profile, layer by layer. The internal assembly (driver chambers, braces, wiring, crossover mounting and acoustic dampening) was done prior to gluing the last side panels in place. I used an orbital sander with 40 grit sanding discs to shape the enclosure and a plunge router to radius the corners and cut the holes for the drivers. The cabinets were finished with rejuvenating oil.

Crossover Design:
3-Way, 2nd-Order All-Pass (APC) – Crossover frequencies are 300 Hz and 2700 Hz. Due to the size of the components, I split the sections up onto two boards, the Band-Pass section mounted in the lower part of the speaker, and the High and Low-Pass section mounted in the upper part of the enclosure.

Conclusion:
With the speakers taking almost a year to complete, I believe my Design Goal was achieved, and perhaps even exceeded. These speakers have a fairly flat response from 30 Hz to 20,000 Hz, detail in the mids and highs with good bass response, and a good looking cabinet that got two thumbs up from my wife.

About the Designer:
I’ve been an audio enthusiast for as long as I can remember. My Dad built a pair of speakers back in the 60s using Electro-Voice drivers that I still listen to today. I’ve been designing and building speakers for the last 15 years. I work as a Mechanical Design Engineer for a robotics integrator. My hobbies include photography and an ongoing project of maintaining a classic truck. I live with my wife of 18 years and an Italian Greyhound.

Project Parts List:

Designer:
Javad Shadzi

Project Category:
Tower Speakers

Project Level:
Advanced

Project Time:
20+ Hours

Project Cost:
Over $1,000

Project Description:
The EPQ-3W is a high end build utilizing Dayton AMT Tweeters and the new 8″ Epique E220CF-8 with carbon fiber cone and high strength neo driver. The goal for this project was to product a dynamic 3-way founded by the 8″ up to 1khz and handing off the snappy and dynamic AMTPRO-4, and featuring exotic materials and a carbon fiber theme.

Design Goals:
The design goals for EPQ-3W were:

– Detailed, accurate flat response

– Efficient and dynamic response, fast transient behavior and sound

– Good dispersion characteristics

– Beautiful to look at

Driver Selection:
AMT2 Supertweeter

AMTPRO-4 Tweeter/mid

Dayton Epique E220CF-8 Woofer

Enclosure Design:
There are two enclosures for the EPQ-3W, the first is the sub enclosure for the open back AMTPRO-4, the purpose of this enclosure is to capture the back wave of the AMT, dampen it and diffuse is. This enclosure is “v-shaped” to minimize the propagation of surface reflections inside the enclosure, then heavily damped with denim insulation material.

The enclosure for the woofer is ported with an internal volume of 1.6 cubic feet, with a 3″ port tuned to 31hz which provided flat in room response to approx 30hz and good extension to 20hz. This enclosure is dampened with denim insulation behind the area of the woofer to dampen the response of the back of the cone.

Enclosure Assembly:
The base enclosure is constructed from 18 ply Russian Birch, similar to Baltic Birch but completely void free and very dense. Baffle, back and top are “veneered” with 3/4″ Chechen wood from South America, a very dense wood with beautiful grain.

Some brad nails were used for initial assembly of the Birch ply enclosure, all other construction is with Titebond 2, 3, Polyurethane glue and dowels.

All drives are flush mounted to prevent any diffraction, baffle edges have a generous 1.5″ 60-degree bevel to minimize diffraction as can be see in the off axis response below.

Crossover Design:
The crossover is a fully passive design

Woofer – 1.15k low pass 12db electrical, polarity reversed

Mid/Tweeter – 1.15k high pass 18db electrical, 9k low pass 12db electrical

Super Tweeter – 9k high pass 12db electrical.

All capacitors are high quality poly sourced from Parts Express, air core inductors are used except for the larger 3.0mH inductor on the woofer in order to reduce resistance as much as possible.

The AMT’s are not flat and a challenge to work with, it’s worth it as they sound fantastic, my recommendation would be to match my baffle dimensions and steal my schematic, I got these drivers to work very well together and operate very flatly.

Tips & Tricks:
Copy my crossover or use the AMT’s with an active DSP

Have fun and learn something!

Google “Javad EPQ-3W” to learn more about this project and to see a detailed build thread

Conclusion:
Every new project for me is an exploration in some new concepts and ideas that I hadn’t tried before, the EPQ-3W project gave me new experience in building a trapezoidal shaped cabinet, working with Chechen wood, Carbon Fiber veneer, using the new Dayton Audio Epique E220CF-8, using an 8” hifi driver up to 1000hz, using AMT tweeters, implementing a super tweeter and a few other things as well.

This was a really fun project and I’m definitely coming away with some new skills, ideas and experience to apply to the next project. These ultimately were for the Midwest Audiofest event in July and they were well received and placed 3rd in Dayton category which I was pleased with considering the stiff competition. Visually the Chechen wood is stunning and I like the contrast with the Chechen wood, but also the parity to the carbon fiber theme including the woofer cone and binding posts.

I love real wood, each board and each grain pattern tells the story of the tree’s life and what it endured to continue to grow and thrive. I love looking at each baffle while I’m listening to these, taking in the differences, imaging what these two different trees experiences that made them grow the way they did.

Sonically these sound great, the AMT tweeters are a challenge to work with passively crossed over as they do not have a flat response, but I was able to get a very flat response considering what I started out with. I purposely left the super tweeter elevated above 10khz as it gives the speakers a nice air and detail to the sound. I tested 6 different crossover topologies before finalizing on what is here, this project would be super easy to do with an active DSP and yield very good sound as well.

The Epique woofer is a good unit, tuned to 31hz in about 1.8ft^3 it provides deep bass to 30 he in room. It holds its composure to over 300 watts with bass heavy tracks, I have measured these speakers at over 110db at 1-meter with my Adcom GFA-5800 clipping lights flashing. In my listening design room imaging is holographic with excellent off axis response virtually anywhere in the room.

About the Designer:
Javad Shadzi is a business owner of company that manufactures automotive performance products, he has 4 kids and a wonderful wife and he resides in the Bay Area of Northern California. His wife is thrilled with all the speaker projects he has planned, in fact she can’t wait to see the next ones he builds!

Project Parts List:

Designer:
Warren Peace

Project Category:
Furniture

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
I picked up a Stromberg Carlson 130-L floor radio at a local second-hand store. I have a soft spot for old radios. They are works of art, unlike today’s black metal boxes. It is now powered by a class a/b 150-watt amp fed by a hybrid tube preamp and Echo Dot streaming Spotify Premium. Everything but the Echo is powered by a surge protector plugged into a TP-Link Smart PLug for voice on/off. Isolation foam covers the inner walls of the cabinet and the speakers rest on isolation mats to mitigate resonance in the old cabinet.

Design Goals:
I wanted to keep the look of yesteryear and add modern sound to it. I also didn’t want the speakers in the cabinet to be permanent. The cabinet is easily upgradable since nothing is permanently mounted. Some of the scars have been left on the old veneer to retain its story/character.

Driver Selection:
I used Paul Carmody’s Overnight Sensations designs for a solid sound and bang for buck ratio.

Enclosure Design:
The enclosure is per Mr. Carmody’s design.

Enclosure Assembly:
I committed antique radio restoration blasphemy and stripped the original finish off the old cabinet. I restained to appear as close to the original as I could. I finished it with 5 applications of tung oil – 0000 steel wool rubbings between coats.

Crossover Design:
Crossovers are per Mr. Carmody’s design.

Conclusion:
I am happy with the way it turned out. My living room now has a beautiful radio for some easy listening.

About the Designer:
I am a communication strategy Marine Corps gunnery sergeant. I manage the flagship social media accounts for the Corps.

I spend my free time in my garage building things. My grandfather was a woodworker, and so is my father. I am not as into as they are, but I picked a few things up. I like woodworking, but I also used metal and electronics.

http://projectgallery.parts-express.com/uncategorized/retro-radio/

Previous build:

Project Parts List: