Designer:
Doublsmm

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Tower speakers with four woofers to provide great low end response and a planar tweeter to work with the woofers and provide a clean sound.

Design Goals:
My goals for these speakers were something that I would be extremely happy with, something that could do everything and something that would look amazing. I’m happy to say I achieved my goal!

Driver Selection:
Woofer Part # 290-218
Tweeter Part # 275-085

Enclosure Design:
Bass reflex, rear ported

Enclosure Assembly:
18mm MDF, nails and wood glue

Crossover Design:
Dayton Audio XO2W-3.5K 2-Way Speaker Crossover

Conclusion:
In conclusion I couldn’t be happier with the end result, these tower speakers sound amazing! The bass is so good that without a high-pass set you barely even need a subwoofer, they are controlled on all genres of music and look amazing! Overall extremely happy with my end result.

Thanks to 123Toid (youtube) for helping me with the graphs for the crossovers!

About the Designer:
My name is Doublsmm and I run an Australian based youtube channel where I build speakers and make videos surrounding them!

Project Parts List:

Designer:
Park

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$500 – $1,000

Project Description:
The PAP audio trio series of open baffle speakers.

Design Goals:
Use left over parts and great drivers.

Driver Selection:
Dayton Audio P220
Eminence Alpha 15a

Enclosure Design:
Open baffle

Enclosure Assembly:
Easy and straight to point

Crossover Design:
Using an electronic crossover with drivers xo ‘ ed st 200 hz with a 12 db roll off.

Tips & Tricks:
This was an Pproved build from PAP with their design and metal bar bracing.

Conclusion:
Great speaker, super imaging, easy to build and perfect for any room.

About the Designer:
I build therefor I am.

Project Parts List:

Designer:
Peter Barilla

Project Category:
Home Theater

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
Bluetooth speaker for my daughter

Design Goals:
Home bluetooth project for my daughter, use wenge wood and spruce wood

Driver Selection:
Model: DS115-8|Part # 295-424
Model: ND20FA-6|Part # 275-030

Conclusion:
Sound is good

About the Designer:
I try make first speaker

Project Parts List:

Designer:
Tom Zarbo

Project Category:
Subwoofers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$500 – $1,000

Project Description:
This project is a dual enclosure subwoofer system that pairs an 8″ High Fidelity Reference Series subwoofer with a 10″ Reference Series passive radiator in each enclosure.

Design Goals:
My wife and I are friends with a couple from church with a good, but slightly older home theater setup. I’ve offered to upgrade their subwoofer system several times over the past few years, and last year they mentioned that they might like to upgrade their subwoofer from an older 12″, low-wattage system to something more modern — rightly surmising that they could find some gains in performance in light of how far subwoofer technology has come in the past 15 years or so.
After some discussion, two things became apparent: First, 20 Hz bass was not necessary; and secondly, whatever I design needed to be on the small side. I suggested two smaller enclosures that could be tucked away… they liked the idea.

Driver Selection:
Since size was a major factor, the driver I ended up using was the Dayton Audio HF 8″ subwoofer along with Dayton Audio’s impressive new RS-based 10″ passive radiator, which is a perfect aesthetic match for the Reference Series line of subwoofers. I added one washer to the PR which yielded an F3 of around 32 Hz… This combo doesn’t need a very large cabinet to perform well.

Enclosure Design:
The enclosure is fairly straight forward. I used 3/4″ MDF for the enclosure, adding an additional layer of 1/2″ MDF to the front and rear baffles to allow the drivers to be recessed and still have enough material for the mounting screws to ‘bite’ into. The enclosure volume is around 28 liters.

Enclosure Assembly:
The enclosure was glued together with Gorilla Glue and is fairly easy to put together with clamps. I rounded over the front horizontal corners of the cabinet and the added bottom base-plate with a 1 1/4″ round-over to add a little extra flair to the design. I also added a single cross brace of 3″ wide 3/4″ MDF to the middle of the enclosure to provide resistance to any flexing.
Since my friend wanted a black finish and knowing how difficult it is to achieve a high gloss black paint finish, I decided to cover the cabinets with birch veneer, stain them ebony black, and apply clear polyurethane as a gloss finish for protection.

Crossover Design:
I intended from the start to use one of the new Crown Drivecore series pro-audio amplifiers to power this pair of subwoofers, as opposed to a more common plate-amp scenario. The crossover duties are handled by that device.

Tips & Tricks:
There are a few things I did that may not be obvious from the pictures. I used a rotary rasp in a drill to make some clearance in the cabinet for the active drivers to breathe. This was not necessary for the passive radiators as they are more ‘open’ since there is no magnet. Also, after drilling the driver mounting holes and driving in the intended mounting screws fully in each hole and removing, I saturated each mounting hole with super glue to help ‘harden’ it up to add strength. I also then applied some bees wax to each mounting screw to aid in insertion and prevent possible snapping of the fastener.
My goal is to construct each project to the level that it almost becomes a “kit” that just needs to be reassembled after the finish has been applied. You don’t want to be engineering things after you’ve applied your finish to your gorgeous cabinets! Do the engineering work before finishing, test fit each part, and you will keep your enclosure looking great after assembly.

Conclusion:
I was surprised at the ‘punchiness’ of the bass this project produced. It digs down low enough for home theater use, but it really excels at reproducing music, and will do so at fairly loud volumes. Having two separate subwoofer enclosures allows you to find the best locations for ‘even’ bass in your listening room, as well as giving you about 6 db more volume overall. The cabinets are small enough to tuck behind a piece of furniture if you want to hide them… or attractive enough to place them front-and-center in your listening room and show them off.

About the Designer:
I’ve been building subwoofers and speakers since I was a teenager and I’m still enjoying it at the age of 46. I keep learning thanks in part to the great folks on the Parts Express “Tech Talk” forum.

Project Parts List:

Designer:
The Foam Core Forte

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
A 2.1 semi-portable boom box using foam core for the enclosure.

Design Goals:
I’ve been messing around with the idea of creating a compact stereo unit ever since our other high priced bluetooth unit started giving us trouble; cutting out, disconnecting intermittently, etc. The project goal was to create a relatively compact, very affordable speaker that covers from ~40hz on up, with hi-fi quality sound.

Driver Selection:
I wanted a selection of drivers that would give me the bass I was after and decent highs as affordable as possible. I picked up the CE65W-8’s (285-143) on sale. And the Tang Band W3-1876S 3″ Mini Subwoofer (264-909) was the logical choice for a small format sub that could get down into the 40’s no problem.

Enclosure Design:
Taking inspiration from builds in another online DIY forum for audio, the enclosure is constructed out of foam core. I included my CAD layout of all the cut pieces in the photos below. The foam core allowed me to complete the whole build in days rather than weeks if I had used MDF, hardwood, or plywood. I simulated the enclosure sizes for the drivers as well as the port specs for the subwoofer in Unibox.

Enclosure Assembly:
I glued the foam core together with good old white Elmer’s school glue. The drying time isn’t great but i feel like the bond it gives on foam core is really strong. The plate amp and drivers are held in place with 8/32 threaded inserts and black allen head machine screws. The Elmer’s didn’t do such a great job adhering the threaded inserts to the foam core, so I came back with some Titebond III on all of them, which seemed to do the trick. I used a cut up moving blanket to line the inside of each section of the enclosure and added a handful of polyfill to the subwoofer section.

Crossover Design:
The plate amp I used has an internal electronic adjustable crossover (from ~30-150hz) and is based on the TPA3118 class D chip. There are two chips. One putting out 2×30 watts to the CE65’s, and the other gives 60 watts to the sub. It’s running off of a 120W laptop power supply. This combo is more than enough to drive the CE65’s and the 1876S.

Tips & Tricks:
Foam core is a fast and easy way to create speaker enclosures. It comes in 3/16 and 1/2″ thicknesses, so plan accordingly.

Conclusion:
Even though the CE65’s only reach to ~16khz and this speaker isn’t as compact as our old bluetooth, it beats the pants off of it in every way. The CE65’s can play so much louder and cleaner with the 1876 picking up from 40-150hz. Jazz and vocals sound great with accurate reproduction of plucked bass notes and piano as well. I can say I’m already very happy with it. Hopefully it gets even better with a little break-in time on the drivers.

About the Designer:
I come from a family of machinists going back generations. I love working and creating with my hands and speaker building has been a great way to combine my interest in design, woodworking and electronics in the perfect way.

Project Parts List:

Designer:
SRL Loudspeakers

Project Category:
Loudspeakers/Cabinets

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
This project entailed building two (2) 15″ PA sub-woofers utilizing the best materials, components, and construction techniques.

Design Goals:
Build an enclosure that had very high SPL, power handling, and excellent fidelity. Maintain small size and weight while still having relatively low Fb and high SPL.

Driver Selection:
290-598 – Eminence Kappalite 3015LF Neo 15″ Speaker Driver

Enclosure Design:
5/8″ Baltic Birch plywood. Entire enclosure is held together with beach-wood biscuits,staples, and glue. This method while taking longer actually ensures a stronger bond and zero chance of vibration and resonant frequencies from fasteners coming loose.

The only fasteners that were used were 10-32 T-Nuts and grade 8 SHCS’s to hold the drivers in place. Truss head screws were used to mount the Penn-Elcom handles and jack dish into place with foam gasket around the flanges.

Crossover Design:
Crossover was electronic by choice of Ashly Protea 3.6SP

Conclusion:
While this project was very time consuming, it yielded a product far superior than any big name sub-woofer that could be purchased. We utilized the finest materials, construction methods, and Eminence Drivers for a high quality product. We also produced a sub-woofer that was lighter and more powerful than anything that could be purchased.

About the Designer:
SRL Loudspeakers (founded 2017)

We were founded on guitar iso-cabinets and quickly moved into designing and building sound reinforcement cabinets for DJ’s and mobile musicians. While lead times aren’t our selling point, our quality and tonal characteristics speak for themselves.

Project Parts List:

Designer:
GKT

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
Under $100

Project Description:
Small boombox for the the home and patio

Design Goals:
Mid century looks and good sound

Driver Selection:
297-428

Enclosure Design:
Plywood inners with poplar exterior

Crossover Design:
Simple butt joints

Conclusion:
Works well but, I ran out of room for my ports. Live and learn. This was my first attempt at one of these

About the Designer:
Newbie audio guy from Dallas. I’m more of a woodworker. Teaching myself how to make these and I’ll be stepping it up as we go.

Project Parts List:

Designer:
Neil Davis

Project Category:
Home Electronics

Project Level:
Advanced

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Act 2 is the second in a series of designs that will result in a compact yet potent wireless 2.1 active system that can be used for computers, TV’s and other entertainment equipment. Act 1 was a subwoofer using a Dayton Audio B-REX cabinet with two Tang Bang W5-1138SMF subwoofers and a Yung SD-100 plate amp. For Act 2, we will remove the B-REX back panel and Yung amp and replace it with a 6-channel amp and a DSP board on an aluminum plate—it will be our own plate amp. This project focuses on that new plate amp design and how the power supply, DSP, amps and WiFi board get mounted and connected. The satellite speakers are described in the write-up for Act 3, and the software and how it gets loaded will get addressed in Act 4.

This project also describes a smaller version of the plate amp that can replace a Yung SD-100 amp. This second plate amp uses an external power supply and a “double-decker” construction to accommodate all the electronics.

Design Goals:
The overall design goal for the Act series is to create a DIY version of the Sonos, Heos or Bose active WiFi speakers, but with better audio quality. It’s hard to compete with these commercial products on size, as some of them are surprising good given how small they are. But by using larger cabinets we can improve on the sound quality and still have the convenience and flexibility of a modern multi-room high resolution WiFi system, at a good price point. And with some attention to materials and detail, we can also make nicer looking cabinets (see Act 3 for some interesting cabinets).

The key to this high audio quality WiFi capability is the electronics on the plate amp. The block diagram shows the components that were used for the plate, and the next sections describe the various components and why they were chosen.

Driver Selection:
The drivers are described in the next project: Act 3. For this project, we needed to select the amplifiers, the power supply, the DSP board and the WiFi module. Each of these components are described in the following sections.

Amplifier: The design goals include a subwoofer with 2-way left and right active 2-way speakers, so I needed an amplifier with a minimum of 5 channels (subwoofer, left woofer, left tweeter, right woofer and right tweeter). Since the Act 1 subwoofer uses 2 drivers, a 6-channel amp was preferred. I didn’t want to deal with heat build-up so I only looked at class D amplifiers. Class D amplifiers switch at high rates and the switching currents and magnetic fields in the output inductors can cause problems when trying to use multiple two-amplifiers near each other. So, the logical selection was the 6-channel Sure amplifier, PE part number 320-307. This amp uses three of the TDA7498 chips synchronized to the same clock, so the amps will not interfere with each other.
The TDA7498 is a well-designed class-D amplifier IC, and we can count on reasonably good audio quality from this amp. The amplifier comes with a small fan to blow air across the heatsink. You will need to remove the fan, as we are going to mount the amplifier “upside-down” and thermally connect the heatsink to the mounting plate. To ensure a good thermal connection, use a .5mm thermal pad between the mounting plate and the heatsink. When you use the 20mm standoffs in the kit mentioned below, there will be enough pressure from the mounting screws to provide a good thermal connection. There is a picture that shows the blue-green thermal pad between the mounting plate and the heatsink.

Power Supply: The power supply is the Meanwell 150W 24V switcher for the larger plate amp, and for the smaller plate you will need just about any competent 100W-150W external “brick” type power supply. A larger power supply could be used, but a nice feature of active 3-way systems is that you can typically get by with smaller amplifiers and power supplies than for similar passive systems. The 100W to 160W power supplies work very well for this application.

DSP/CPU Board: As you can see from the block diagram, there is a lot happening on the DSP/CPU board. I used a custom design for this board to keep the circuitry compact and avoid wiring between submodules. The CPU, DSP, DAC, local power supplies, and Bluetooth/USB are connected by traces on the board, and the only external connections are the audio lines (which use RCA phone jacks), power and some serial connections.
Because this is a custom DIY board, you will have to build this board yourself or find someone who is making them. Design files for the PCB and some construction details are available on the Audiodevelopers web site. It is not an easy board to assemble because of the large number of SMD devices. However, there will be an updated version of this board that will be much easier to assemble. The new design will use a greater number of pre-assembled modules to reduce the parts count and make assembly much easier. That design will be posted on the Audiodevelopers web site and be available for free once it is finished and debugged.
Although this plate amp design uses the custom DSP board, it is possible to use separate modules. For example, you could use a miniDSP board or FreeDSP board, but would need to add an Arduino CPU, a Bluetooth board, and an extra digital-to-analog converter board. That’s not too hard to do, but the size and cost and wiring complexity make that approach cumbersome. There is a place reserved for an article that shows how to use these other modules on the Audiodevelopers web site (see the Article on Case Study #2).

WiFi Module: WiFi based wireless speakers are the rage and no doubt the future of home stereo. According to a report from Strategic Analytics, this market grew by 62% in 2016 to 14 million units. Sonos was one of the early market leaders, but Bose, Denon, Amazon and others have jumped in with products that range from background music devices to replacements for the home stereo. These WiFi speakers allow you to set up a home network of devices with routing of various sources to any room in the house. The WiFi speakers have built-in Internet radio (XM, Pandora, Spotify, Amazon, Google, etc.) and allow music library playback with smart phone control.
Parts Express carries two different WiFi modules—the WFA02 (#300-576) and the WFA28 (#300-577). I used the smaller (and cheaper) WFA02 module. Both are controllable with the same smart phone app, and both offer the features we need for this project.

Enclosure Design:
The electronics are mounted on a plate that fits in the back of the Dayton Audio SWC1-BK 1.0 cu. ft. cabinet (PE #302-836). This cabinet is well built and it provides plenty of space for the Act 2 electronics.

The first step in building any plate amp is to lay out the parts so they fit on the plate. This can be done by using “paper dolls” of each component or using a computer drawing program. I used Powerpoint to create the components using a 2:1 scale, and move them around on the plate to make sure everything would fit. The Act 2 plate layout graphic shows that the parts fit with little room to spare. There is also a layout for a comparable plate amp using the Sure DSP boards. Even with the extra modules, there is enough room on the plate for everything. But with the Sure modules, there isn’t enough room to use the bulky RCA connectors as interconnects, so the cabling will be more involved.

The SD100 replacement amp is much smaller than the 12.5” square plate amp, and it is clear from the layout that the power supply will need to be external. And even without the power supply, the 7” by 8” plate needs a second layer to make sure the components fit. I used a 1/8” thick plate of aluminum that I had left over from my wife’s business. The guys in the machine shop where I worked had made her some nice aluminum cookie sheets in exchange for some cookies, and I was able to cut the cookie sheets down to the right size on a bandsaw. So, if you don’t have extra aluminum plates laying around, you will need 2 pieces of 6” by 6” 1/8” material. One of the pictures shows the double-decker construction for the SD100-sized amp.

Enclosure Assembly:
The assembly phase involved a lot of drilling, component mounting and wiring.

Drilling: It’s important to drill all the holes you need to mount components before painting and assembling the parts. Drilling is messy, and you don’t want metal flakes shorting out circuitry that is already mounted. The hole locations and drill bit sizes and countersinking will vary depending on the selected connector hardware and the modules you use. Take your time on this important step, and keep double-checking for the right fit for each item. Once the holes are drilled, you can sand the plate with increasing fine paper until you get the “texture” you desire. You don’t need to paint the aluminum plate, but a coat or two of flat black will be less conspicuous and easier to get past your wife.

The power supply has pressed-in threaded inserts for mounting that are difficult to accurately locate. Fortunately, the power supply has a plastic insulator that easily slides out after removing one screw located near the power input connector. Just mark the insulator with a pencil through the mounting holes and then slide out the insulator sheet to use as a template. For the DSP board, just make a printout or the PCB or one of the Gerber files to locate the mounting holes. Once you drill these holes for the M3 screws (1/8” will give a tight fit), countersink the cap screws with a 5/32” drill to a depth of 1/8” from the front side of the plate.

The Speakon and Powercon connectors require an “oddball” 24mm drill size. Since this is not a common size for most drill bit kits, you may have to order one online. I bought a 24mm “Roman Carbide” Forstner bit from Amazon for $13. However, after drilling just 2 holes in the aluminum plate, one of the carbide blades broke off. By the time I was done with all the holes, both carbide blades had separated from the body. You might want to either buy a better drill bit or else be very careful to not press too hard with the budget drill bit.
Notice that many of the components on the plate require countersinking from the back due to the thickness of the plate. You might be able to find some panel-mounted switches and connectors suitable for ¼” panels, but you will probably have a better selection of components if you just countersink everything with a large bit. If you are building the SD100 version, you might need to shop around for a heavy-duty power connector. There are 5.5mm/2.5mm barrel connectors that can handle 5A, but the ones PE carries are only rated for 3A.

You don’t need mounting holes for the WiFi module, as that plastic box can be affixed with Velcro or the 3M mounting strips used for toll road transponders.

Assembly and Wiring: Assembling the components to the plate is fun, as you get to see the amp take shape. But wiring seemingly takes forever, and there is little joy in crimping pins on small ribbon cables or soldering RCA connectors to shielded cables. Plan to fight the tedium by having good beer or stronger spirits to keep you amused, and don’t get frustrated at the amount of time it takes—that’s just the nature of this task.

A step that requires some extra care is wiring up the external antenna to the WiFi module. You only need to do this if you can’t get a good WiFi signal with the module hidden behind that mounting plate. If you are close to your WiFi router you will probably get an adequate signal. But our router is in the basement, so I wanted an external antenna, even though I knew this would void the warranty. Carefully open the WiFi module using a knife blade to pry off the cover. Then remove the 4 mounting screws holding the board to the plastic housing. The button for the WPS switch is probably going to fall out, so make sure you don’t lose it on the floor. Then remove the antenna connector—it is one of those tiny U.FL connectors that you see in laptops, and it’s got hot melt glue that you need to pull off. I used a U.FL to RP-SMA cable assembly (Mouser part #741-080-0001) to allow using a nice external antenna. With the external antenna, the signal strength was about 98%, even though I was two floors up from the router. If you have a hot melt glue gun available, put a small blob of glue on that UFL connector to make sure it doesn’t fall off the board (that happened to me!). When you put the board back in the case, make sure you remember the WPS button, because you will need it to get the WiFi module to join your network.

Unfortunately, the original wiring approach had issues with grounding. The WiFi module requires +5V at around 300ma, and most of that current is for the WiFi signal, which in effect is a small radio station. When you try to connect the audio to the amplifier or DSP, all that return current is flowing through the ground, and it creates an audible noise like digital chatter that is annoying. It would be nice if the WiFi module had separate analog and digital grounds that could be connected independently, but that’s not the case. There may be other ways to fix this grounding issue, but the easiest approach I found was to either use a DC to DC isolating convertor for the WiFi 5V, or else run the WiFi from a USB charging module. The noise goes away once the power is isolated. The new version of the DSP board will include the DC-DC isolation module, but for this prototype I used the USB charger.

Crossover Design:
The crossover is active, using an ADAU1701 DSP chip that is controlled by an Arduino CPU. Act 3 describes the active crossover design, and Act 4 describes the software that is used to control the DSP. Act 4 also describes the cell phone application that is used to select the crossover and EQ.

Tips & Tricks:

This project requires loading software into the CPU. Unfortunately, software is never done, so it is helpful to extend the USB connection to the CPU by adding a connector to the outside of the box. The Neutrik NAUSB-W-B (PE part #092-279) and a short micro USB to USB cable (PE #130-572) let you easily provide an airtight USB connector on the subwoofer front baffle. There’s not enough space on the back panel using the layout shown here, but having the connector on the front is a convenience.

Another important tip is to make sure you set the switches on amplifier that adjust the gain before you mount it to the plate. Since the amplifier board gets mounted “up-side-down”, these switches will not be accessible once the amp is installed. There are some calculations that you can do to determine the best gain value for each channel, based on the power supply voltage and the sensitivity of each driver. For many designs, the best switch settings will be “weak” (25.6dB) for the tweeter and subwoofer and “low” (31.6dB) for the woofer or midrange.

Conclusion:
This is a complicated project, and it is only part 2 of a 4-part series. Most of the real complexity is hidden inside those powerful modules: the WiFi adapter, the DSP, the CPU, or the Bluetooth adapter, the 6-channel amplifier and the power supply. But there is still a lot of cutting, drilling, wiring, assembly and finishing to complete this phase, and then there’s that big step of loading software in part 4 that still awaits us.

This is still more of a prototype than a finished solution, but it helped identify what is needed for DIY’ers to make a high-end DIY Sonos/HEOS/Bose clone that they can customize and use drivers of their choice. This project made it clear that the DSP board is a good step forward, but that a next-generation version will make this project easier to build and simpler overall. And there might be a kit down the road to make that DSP board easier to build or there might be something fully assembled that you could purchase.

But even as a prototype, this project is fun to use and extremely satisfying. The Dayton WiFi software is not as “professional” as the Sonos or HEOS equivalent, in that there are fewer “stations” (for example, Sirius and Pandora are not natively supported) and less integration for some of the existing stations such as Spotify. But there is still a good variety of Internet streaming sources, and the multi-room routing and lossless audio is great. The WiFi module can keep music libraries on a memory stick, or it can play from music libraries located on your phone and other computers. That’s a lot of flexibility and fun, combined with high quality audio.

The DSP board adds even more fun and excitement. There is an Android app that will run on a cell phone to select crossover slopes and frequencies or specify EQ, baffle step compensation and bass boost. Those features will be described in the next project (Act 3).

About the Designer:
Neil is a member of the PE speaker builder design team (SBDT). He is a retired engineer who has enjoyed watching the speaker building technology evolve and he wants to help bring those technologies to the DIY community.

Project Parts List:

Designer:
Neil Davis

Project Category:
Loudspeakers/Cabinets

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Act 3 is the third in a series of designs that will result in a compact yet potent wireless 2.1 active system that can be used for computers, TV’s and other entertainment equipment. Act 1 was a subwoofer using a Dayton Audio B-REX cabinet with two Tang Bang W5-1138SMF subwoofers and a Yung SD-100 plate amp. For Act 2, we came up with a 6-channel plate amp with WiFi and DSP. And now we get to build something a bit simpler that can take advantage of the DSP horsepower in that plate amp. The details of the software will get addressed in Act 4.

Act 3 is two sets of speakers that are interchangeable–that is, either set could be used with the plate amp described in the Act 2 project. One set uses a cabinet made from locally-grown cherry and the other set is built using solid zebrawood. Both speakers use the same connector and channel assignments for the DSP, and by simply reprogramming the DSP from a cell phone, either set of speakers can be used with the subwoofer and amplifiers. Although these are active speakers, one of the speakers has an interesting twist by using an unusual AMT tweeter combination with a passive crossover at 5000Hz.

Design Goals:
The overall design goal for the Act series is to create a DIY version of the Sonos, Heos or Bose active WiFi speakers, but with better audio quality. Act 1 gave us a medium-power subwoofer to fill in the area below 80 to 150 Hz. The main design goal for this phase, Act 3, is to develop a generic satellite 2-way active speaker, where the design supports a wide range of 3” to 5” woofers with many different tweeter options. We will show two different variants of interoperable speakers—where you can quickly plug in one or the other, and select the DSP profile that optimizes each variant. Another design goal is to show what can be done with real hardwood cabinets that can have a high “spouse approval factor”.

Driver Selection:
One of the nice benefits of using separate amps and DSP in active speakers is that driver selection tends to be a lot less critical than with passive designs. If you use drivers that behave reasonably well in their assigned frequency band, you can usually use them successfully in an active speaker, even though they may be difficult to work with in a passive design. So, this was an ideal opportunity to draw on my stash of drivers in the attic and put some of those unused Christmas presents to good use.

The cherry cabinets used some SEAS Excel W14CY-001 woofers purchased many years ago, along with the Tymphany (Vifa) NE25VTA-04 aluminum tweeters. The Excel woofer uses a magnesium cone with prominent breakup modes in the 10KHz area, and it has a well-deserved reputation for being a “difficult” driver to work with. However, a steep 8-pole crossover at 2KHz or so will completely suppress those breakup artifacts. And this relatively low crossover point is not a problem for the ¾” Vifa tweeter, especially with that steep filter.

The tweeter selection for the zebrawood cabinet was one of those ideas that gets stuck in your head and won’t leave you alone. Every time I looked at those zebrawood stripes, I was reminded of the AMT drivers that PE is carrying—the AMT mini-8 and the AMT-2. However, neither of those tweeters was “ideal”, as the mini-8 didn’t extend low enough to integrate well with a 4” or 5” woofer, and the AMT-2 suffers from some “beaming” for frequencies over 5KHz due to the relatively large size of the diaphragm. So, I decide to use both tweeters, with a passive crossover at 5K between the two. This passive crossover was a simple 2-pole Butterworth filter. Because the AMT impedance is almost entirely resistive, I was able to use textbook values for this crossover.

The zebrawood cabinets were just the right size for the Dayton RS125 4” driver. I had a couple of speakers that I intend to rebuild that already had the RS125 driver, but I decided to save those cabinets and drivers for Act 5, or “Curtain Call”, as it will probably be called. Since there aren’t too many other drivers with the right dimensions, I ended up buying the MCM 4. 5” driver, 55-5655, to give that new driver a listen. In retrospect, the RS125 would have been a better choice, since the MCM driver is now a special order item.

Enclosure Design:
Both cabinets were sealed, in the 4L to 5L range. This internal volume results in an F3 of 90Hz to 120Hz for the drivers that were considered for these cabinets. Since these will be used with a subwoofer and an active crossover for the subwoofer to woofer transition, the box dimensions are not critical. In fact, I simply used the amount of wood I had to determine the box final dimensions, and just scaled everything to achieve a “golden ratio” (1.6) of height to width.

If the drivers and cabinet were a bit smaller, using a 3” to 4” driver, it might be worth looking at a vented cabinet design to extend the response to allow a low crossover to the subwoofer. Alternatively, some additional filtering could be provided in the DSP to electronically extend the response.

Both cabinets used a removeable front baffle that is affixed using tee nuts and machine screws to cleats glued to the internal cabinet walls. The removable baffle makes it easy to service the drivers or to repurpose the cabinets with a different set of drivers. The speakers still need grills, but I’ll make some simple covers later.

A key design feature is the use of Neutrik Speakon connectors. They are reliable, easy to use, and they allow swapping in different cabinets without worrying about polarity and getting the right channels to each driver. I always count from the top and use the 1+ and 1- pins for the tweeter and 2+ and 2- for the woofer. Mounting the connectors is easy: just use a plate made from a 2” by 3” strip of ¼” wood, and then drill the 24mm hole and mount the Speakon to the plate. Cut a 1-1/8” by 1-1/2” opening on the back of the cabinet, and then mount the plate to the inside of the cabinet with the connector sticking through the opening. The connector should be at the “bottom” of the rectangular opening with the latch at the top so there is some room at the top to insert a fingertip to release the connector. If you use a right-angle Speakon connector, it will stick out about ¼” from the back of the cabinet, making a very nea t and compact connection. Make sure the top of the rectangular opening is at least 5 inches above the cabinet bottom so there is room for the connector and the wire.

Enclosure Assembly:
As already noted, one of the cabinets used locally-grown cherry from our cabin in Western Maryland. This wood has a large amount of figure, so it would be classified as curly cherry, yet it is very stable and easy to machine. When used with a penetrating finish such as tung oil or boiled linseed oil, the wood takes on a rich depth that creates refraction patterns of dark and light that move as you change viewing position. This interesting and visually appealing scattering of light is called chatoyance.

I had purchased a Porter Cable dovetail jig a while back and decided to use it for the first time for these cherry cabinets. Dovetail joints are amazingly strong, and are overkill for ¾” wood. I did some test runs, and got some perfect 90-degree angles that were amazingly strong even without glue. But the strength wasn’t the objective here: dovetail joints simply look cool. It takes a couple of test runs to set up the depth and tightness, but the instructions with the Porter Cable jig are thorough. After a few good runs, I did all the tails and pins and then spent about 20 minutes cleaning up the router shavings. The best way to work with the dove tail fixture is to have a friend hold a dust extractor hose under the material as you use the router. Otherwise, be prepared to be coated in a heavy layer of shredded wood.

The zebrawood was quite different from the cherry, in that zebrawood is not straight and stable, and it does not machine well. This started out as a 2” thick plank that I sliced down the middle on a band saw. By the time I reached the end of the plank, the wood curved by over ½” along its length—there was a lot of stored tension that got released. This time I used the box joint templates rather than the dovetail template to keep the cut lines parallel to the grain.

After squaring up the pieces on the table saw and cutting the box joint fingers, I had to use clamps to get the pieces to fit into each other. Zebrawood has a lot of tension built up from the light and dark bands having different hardness and expansion properties, and making square joints with this wood is a real challenge. However, this time the box joints were not just decorative—they did a good job of forcing the corners to fit and stay square during gluing, and the interlocking fingers should keep those joints stable and strong. The zebrawood also tends to splinter in long strings—it doesn’t machine as nicely as other hardwoods. But going over the box joints with a razor blade helped remove all the fine threads left by the router.

With a couple of coats of penetrating sealer/varnish, the zebrawood starts to show its beauty and richness. The light and dark areas absorb the finish differently, but by using lots of coats (about 10) with fine sanding (1200 grit) in between, the finish starts to look uniform.

Crossover Design:
The key to achieving the goal of satellite design flexibility is the DSP on the plate amp. The DSP uses the popular ADAU1701 chip, but with a local CPU host that can calculate the filter coefficients from simple commands sent from a cell phone. So, if we change drivers or crossover points, our generic design can be tweaked and optimized by simply sending some commands from our cell phone.

There are many benefits from using DSP and dedicated power amps for each driver, but the main benefit is that it simplifies the crossover design. Specifically, the designer doesn’t need to deal with the complexity of passive crossover design. Passive crossovers interact with the driver impedance, so the designer needs to have reliable impedance measurements. Since the impedance of a typical driver changes with frequency, and because many drivers have different impedance curves, the passive crossover network needs to be designed for a specific set of drivers, and will only work well with those drivers. For an active system, the driver impedance curve is irrelevant, as the low impedance output of the amplifier completely “swamps out” the driver impedance. We still should measure the amplitude response of the driver, but for many drivers that are “well behaved” in the intended frequency range, even the amplitude response of the individual drivers can o ften be ignored.

The DSP crossover for the woofer and tweeter can be selected from a simple menu that currently includes 5 different crossover types (one-pole Butterworth; 3-pole Butterworth; 2-pole Linkwitz-Riley, 4-pole Linkwitz-Riley, and 8-pole Linkwitz-Riley). The crossover frequencies can be selected from 7 different frequencies (1200Hz, 1600Hz, 2000Hz, 2400Hz, 2800Hz, 3200Hz, or 3600Hz). Similarly, the subwoofer to woofer crossover can be selected from 4 different types and 5 different frequencies. These menu options are in a look-up table, and could easily be changed by either changing the code or downloading a custom table.

The DSP also provides baffle step compensation, selectable from 8 different frequencies ranging from 300Hz to 1000Hz, and 7 different levels from 0 to 6dB. Additionally, there is a 9-band equalizer that can be used to tailor the frequency response. And the volume of each driver can be adjusted over a 10dB range.

These DSP functions give us a lot of control over the drivers, and the settings are saved in non-volatile memory (EEPROM). So, we can optimize the settings for a given set of drivers and save those settings, and recall them later. By using a standard connector for the satellite speakers, we can quickly connect different cabinets that have different drivers, and simply recall the optimize settings for each speaker. There is a lot more discussion about the software and DSP control in the Act 4 write-up, which is the next one in this series.

Tips & Tricks:
Solid hardwood cabinets can look beautiful, but make sure you select the wood wisely. The wood needs to be thoroughly dried to be stable, and some of those exotic woods with interesting grain patterns—such as zebrawood—can be difficult to work with. It’s also helpful to consult one of those wood shrinkage charts to understand the amount of movement likely for different species in varying humidity conditions. Some hardwoods may not be suitable for areas that have large changes in humidity, particularly if the cabinet has large panels.

Dovetails or box joints aren’t really needed with strong modern glues, but they can useful for wood that tends to curve and for thinner wood where the gluing surface is small. However, they look nice and they help showcase the solid wood construction. The dovetail template is essential for those joints, and the template is easy to use. There is a lot of end-grain cutting with dovetails, so make sure you have sharp router bits and use a hardwood that doesn’t have excessive tear-out. I ended up cutting some extra end panels for the cherry cabinet because the wood split off two of the end pins. Take your time with the router and don’t try to cut out the tails or pins too quickly.

Conclusion:
After that complicated Act 2 project, this one is a refreshing break. But that’s the nice payback from using a DSP in the plate amp: the speaker design is easy, with no custom passive crossover to worry about. And we can use a wide range of drivers, and even use some of those hard-to-work-with drivers that take too many components to tame into submission. And we get to work with nice woods, which beats the drudgery of wiring any day.

The woodworking takes time if you are starting with rough cut wood, but by using precut and sanded lumber this project can be completed quickly. The cabinets can also be made from MDF, of course, and finished in many ways, or you could use prefinished cabinets or knock-down kits. But since these are the speakers that will likely end up on the desk on next to the TV, it’s worthwhile to use materials and construction methods that look nice.

The goal of this project was to describe a generic satellite design that can be used with the Act 2 sub/DSP. We’ve shown two different variations, and in the next article (Act 4) we’ll show how to load the software into the CPU to control the DSP and we’ll provide the instructions for downloading the cell phone app.

About the Designer:
Neil is a member of the PE speaker builder design team (SBDT).

Project Parts List:

Designer:
GKT Design Co.

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
A 36″ portable Bluestooth speaker.

Design Goals:
To get a device that looks good enough and sounds good enough for it to be your one device. Home audio, patio or pool, or tailgate.

Driver Selection:
295-424

Enclosure Design:
This first attempt is in pine to keep cost down until I figure out how to construct it. I used a maze vent to get a bit more low end which worked out well. It was a totally guess on my part. The design software made my head hurt. Sounds Great!

Enclosure Assembly:
Brads and glue

Crossover Design:
High pass filter plate to the tweeters (cost saver) and I passed through direct to the woofers.

Tips & Tricks:
My only tip is to make sure you have enough room for all the electronics!

Conclusion:
The sound is great, the battery life is great, the bluetooth signal need work on the next one, the looks turned out well. I will however do much better on the next one.

About the Designer:
Maker from Dallas, TX. Music nerd and learning wood working. Learning…. Learning…. hopefully someday selling

Project Parts List:

Designer:
David Hall

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Longboard Line Array – There is something alluring about line arrays that caught my eye. And after doing some research, I decided to dip my toe in the water and build a “Reader’s Digest” small version of line arrays.

Design Goals:
• Cost effective
• Sound great
• Drivers individually amplified with low cost low noise PAM8403 3-watt stereo amplifiers
• Visually striking

The first goal was to cut my teeth on line arrays without breaking the bank. You’ve heard the expression, “Good, cheap and fast – pick two and call me back.” Well, this build was good and relatively inexpensive (if I don’t consider my time), but did take some time. Secondly, despite the frugal budget objective, I wanted the arrays to produce decent quality sound. That being said, considering the cost of my choice of driver, the CE40P-8, my expectations were not too high. Yet in the deep recesses of my mind, I was hopeful the arrays might have some potential for “presence” and sound as if performers were actually in the room (or at least the next room). Also, to maintain a low cost of the project I wanted to power each CE40P-8 driver with the inexpensive PAM8403 stereo amplifier boards as they are low cost (about $1) and they are advertised as “low noise without a lot of external noise filtration capacitors and inductors.” Yep , I admit it. I was lured into the “cheap” trap. Lastly, I wanted the aesthetics of the arrays to be visually appealing. A large black monolith with lines of drivers installed was out of the question. The arrays had to pop with colors found in natural wood. As far as the design style, I designed this prototype to loosely emulate the old school look of “longboards”, the surfers of the 60’s used to ride the waves.

Driver Selection:
CE40P-8 — I was intrigued by the claims made in the Parts-Express video on CE40P-8 (which is no longer on the site at this time 8/10/17). Initially, I ordered three drivers as experimental drivers to see how they actually performed. According to the datasheet and the video, these cute so-called “full-range” little drivers (that look like something Santa’s elves would make) should handle the high end as well as the mid-range. As an avid fan of physics (yes I am a geek), I had no delusions these tiny 2-watt CE40P-8 were capable shaking the art off the wall. The initial test of an unmounted driver sounded like I bought the best speaker one could buy for 10 cents. After some cursory calculations I built one small enclosure for one speaker and a dual chamber for the other two, both of them ported. I was pleasantly surprised so I asked the elves at Parts-Express to ship me 24 more drivers. I tested them all using the DATS V2 audio test system and entered the test data into Excel. The statistical distribution of all the drivers was surprisingly consistent +/- 5% on critical Thiele small parameters. No drivers were rejected so basic driver quality was not expected to be an issue in the build.

Since 12 of these were going into each array, at a listening distance of 3 meters, the calculated SPL obtained should be about 87 dB, which should be enough for most listening in the home (when the wife is not around). The final measured values from each array was actually closer to 85 dB.

The PAM8403 circuit boards proved to be rather noisy and unreliable. The “low noise” was not as low as I had hoped and produced an intolerable hissing that irritated me enough to toss them into the trash. After wasting too much time with different filtration schemes, I abandoned this approach. Instead, out of frustration I changed direction and wired all the drivers in each cabinet in a series-parallel configuration yielding a little less than 6-ohms for each array and used a Lepy LP-168 Plus Bluetooth 2.1 channel amplifier to drive the arrays as it was the closest thing to grab. This amp enabled me the choice of either a 3.5 mm input jack or Bluetooth and had treble and bass adjustments for the arrays and a sub.

Enclosure Design:
The design was first modeled using Sketch-up to determine the number of board-feet of lumber to purchase as well as the port and driver positions. Calculations dictated that each driver needed an 86 cubic inch chamber with a ½” diameter port 1 ½” long. This configuration yielded an Fb = 106.8 Hz. Due to the narrow design and the number of partitions supporting the sides no bracing was needed.

Since one of the goals was to have visually appealing line arrays, I made the speakers out of solid wood instead of MDF. I was going for the “old school” accent striped look of the longboard design of the 60’s. For contrast in color I selected maple and cherry.

Because cross-sectional dimensions of the cabinet are small and the wall thickness was relatively thick (read dense) any absorption of acoustic energy from the drivers was minimal and did not produce standing waves or introduce distortion or significant dead spots in the frequency spectrum.

Enclosure Assembly:
I jointed and planed inexpensive rough-hewned lumber to make the wood flat with clean orthogonal edges. Varying widths of wood were then ripped to random widths to produce visual contrast in the two arrays. The strips of lumber were then laminated (glued) together and planed. Once all the lumber was milled, jointed, ripped, glued, then cut to size, I used a router to cut dados in the side boards to accommodate the individual chamber partitions. Because the cabinets are solid wood I needed no fasteners, screws or nails; I used simple glued butt joints as they provided enough bonding surface area. The ports were made by gluing small blocks into the inside of the driver panel then drilling through the front panel and block once the glue had dried.

The partitions are made on ¼” plywood. I glued and sealed them into the cabinet slots. Due to the small size of the chambers (and the size of my hand), I initially installed every other divider panel in order to leave enough room for my hands to install the drivers. The holes in the front panel for the drivers were cut using Freud scalloped edge Forstner bits as this yields a clean smooth cross-grain edge compared to most other bits available. The edges of the holes were rounded with a ½” round-over router bit. The wood was sanded to 220 grit then sprayed with 3 coats of gloss polyurethane followed by one coat of satin polyurethane.

Next, the drivers were installed as were the remaining partitions. As before, the panels were glued and sealed. To seal the back of all the driver chambers, I made a backplane using contact cement to bond a ¼” sheet of closed-cell neoprene foam to ½” plywood. The speaker wires were then routed through small holes in the backplane. The neoprene covered backplane was compressed into the back of the speaker and secured to the cabinet by driving screws into the sides thereby sealing each individual chamber. The neoprene might serve as minimal acoustic insulation, however I don’t think it provided any significant effect or improvement to the sound. The drivers were wired in series-parallel to achieve about 6-ohms. Note: I initially tried stuffing each chamber with acoustic fill, but the sound became somewhat muddy so I eliminated it from the design.

There remained about 1.5” inches of space in the back of the arrays. This allowed enough space for hardware to hang the arrays on the wall as well as install crossover or DSP. These would be a great left/right speaker for a home theater system (which one day they might become part of a 5.1 system).

Crossover Design:
None.

The speaker configuration yielded relatively good results for such small drivers which is why I selected the CE40P-8. As one would expect, the bass portion of the spectrum was thin but better than expected. To provide the needed low end, I built a ported subwoofer using a Dayton Audio DCS165-4 6″ Classic 4-ohm subwoofer. I chose this driver because the frequency response curve is very flat in the low end and nicely tails off at about 2kHz. This configuration allowed me to forego the need for a crossover. The subwoofer cabinet was constructed of ¾”MDF and tuned to about 40 Hz. I had enough leftover maple and cherry wood to fabricate the veneer needed to cover the subwoofer.

The testing was performed with a Lepy LP-168 Plus Bluetooth 2.1CH amplifier. Fortunately, the Lepy LP-168 has independent bass adjustments that enable me to easily balance the low end from the sub with the arrays. For testing, the bass and treble adjustments for both the subwoofer and arrays were set to mid-point.

Tips & Tricks:

Be patient. Allow yourself time as the CD40P-8 are very small and the spaces to install are tight.

Conclusion:
This was a fun build that looks and sounds pretty great. My goal was to build line arrays using cost effective drivers, and we’ll stamp this one a “success.” While these line arrays aren’t going to rattle the art off the wall, there is certainly more than enough volume to fill the room with no perceptible distortion.

Overall the build was labor-intensive because of the sheer number of drivers and woodworking involved, but the work was worth it. The quality of sound was delightful and greater than expected. These currently sit next to our Klipsh RF16 speakers and sound as good or better though not capable of handling higher volumes than the Klipsh do. Still, these fill the room with quality sound and I’m pleasantly surprised with the results. We’re now using them as our primary choice of speakers.

The listening test included jazz, classical, a cappella, rock, symphonic, blues and hip-hop. The subwoofer was truly needed to supply the lower end for the rock and hip-hop genres. The vocals of the a cappella group Home Free had great presence, especially in the mid-range. They image very well, especially with about seven to eight feet between arrays. I got some low-end excursion noise from overpowering the drivers. To protect the drivers from bottoming out from lower frequencies, I installed an inductor to shunt the lower frequencies as I noticed slight distortion at higher volumes. The subwoofer will do the heavy lifting just fine.

I was disappointed that the PAM8403 amplifier boards did not produce the results I wanted, but in the end, the Lepy amp allowed me adequate adjustability in the sound profile.

The next array build will include larger drivers accompanied with tweeters, a miniDSP HD, and possibly the LinkPlay EVB kit with A31 Wi-Fi Audio Module capable of Bluetooth and Alexa Voice service.

About the Designer:
David Hall is an avid custom speaker and home theater designer, and the owner of SounDesign. The favorite part of his job is speaker design and fabrication. His enclosure designs start with sketch pad and pencil. A lot of paper finds its way to the trash can before a design goes to CAD (computer-aided design). He pursues unique cabinet design and drivers that offer his clients both the look and quality of sound they desire. David’s philosophy is audio should be as pleasing to the eye as it is to the ear. It has to look as good as it sounds and it must sound awesome! David focuses on choosing drivers with optimal qualities to achieve the finest sound in order to diminish or avoid the electrical and acoustic challenges of crossover design. He has, in one way or another, been involve with electronics since he graduated from DeVry (decades ago). Music is a major source of enjoyment in his home. In his younger years David was a bass trombonis t in jazz ensembles and sung and played in several venues throughout the southwest. He is a desert rat living in Phoenix, Arizona with his hot wife, Debbie. Occasionally, in the cool months, he enjoys a good cigar and bourbon (when his wife is not around).

Project Parts List:

Designer:
Jamie Walder

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
portable/stationary Stereo bluetooth speaker

Design Goals:
The Goal of my design was to create a speaker that is portable yet can be docked on a stand when home.

Driver Selection:
I selected the Tang Band W3-214 for the main forward facing speakers in this design for there full range crisp sound and the look they have against american white oak. i also incorporated 2 Tang Band W2-1625SA to hit the lower end that the full range drivers couldnt quite hit

Enclosure Design:
The design is a simple, modern clean design based mainly on aesthetics. all the drivers are isolated with the recommended capacity as quoted on their parts express info pages. the woofers however have a little less room but when docked on the solid oak functional stand, the lower woofer is free to resonate in the stand giving a much fuller sound

Enclosure Assembly:
the enclosure is assembled using rabbet joints all round and finished with a roundover on every edge. the internal compartments are made in ply and butt jointed with glue only.

Crossover Design:
Crossovers used are only on the woofers and are simply a 1mh inductor in series with a 20uf cap in parallel after the inductor but before the woofer. this cuts the highs but still keeps the lows and some mids up to about 500mhz-1khz. the full range drivers need no crossover.

Tips & Tricks:
Work hard and always test on scrap if you are in doubt as to whether or not your cut or drill hole is going to work out.

Conclusion:
The over all design and appearance i think is great. the Amp board it perfect for the application. the drivers sound better then expected thanks to the addition of the woofers. a little less portable then i would have liked as is very heavy.

About the Designer:
Maintenance man from south england, Wood working is a hobby and i hope to one day earn from my hard work.

Project Parts List:

Designer:
Rasmus Munk Larsen

Project Category:
Tower Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$500 – $1,000

Project Description:
Here is my “Birthday Build” for my friend Mike, commissioned by his wife as a surprise present for his birthday. Mike, our wives and I love to get together to listen to music. Mike is a constant source of learning about cool artists, old and new, for us, so I really wanted to build something excellent that we could enjoy together over the years to come.

Design Goals:
My goal was to create a great sounding and beautiful floor-standing speaker, putting to use all the skill and knowledge I have accumulated over the last few years of building, experimenting, and listening to more experienced speakers designers, here on Parts Express and other online forums.

Driver Selection:
The speaker uses a Vifa XT25BG60-04 1″ Shielded Dual Ring Radiator Tweeter, and a Peerless 830875 6-1/2″ Nomex Cone HDS Woofer. I have used the Vifa XT25 in previous projects and love the very detailed and neutral sound it has. I also think it creates an incredible 3-D soundstage. I had not used the Peerless Nomex cones before, but saw many people recommending them. I am very happy with this choice as it was easy to work with, plays surprisingly deep, and looks great.

Enclosure Design:
The enclosure is a 25 liter bass reflex box tuned to 42 Hz. I simulated it in WinISD.

Enclosure Assembly:
The cabinet has 3 internal window braces, foam dampening (mattress topper) and a 3″ port made from ABS pipe, using a 60 degree knee to make it fit, and flared on the outside using a chamfer bit. The sides of the baffle have a 1/2″ roundover. The cabinet is covered in zebrawood veneer and finished with Polycril.

Crossover Design:
The crossover is adapted almost exactly from a design by Jay a.k.a. Brewski in an old thread here on Parts Express: http://techtalk.parts-express.com/…/45553-hi-i-am-new-and-n…

I used a mix of Audyn and Jantzen (the lower end ones) for the series caps and NPE for the large caps in Zobel and the RLC. Inductors were Jantzen. I added an L-pad (not shown in diagram) consisting of a 3 Ohm resistor in series and an 8 Ohm resistor in parallel to match sensitivity and reduce an upwards tilt of the tweeter response.

Conclusion:
I am very happy with the way these speakers came out, both in terms of looks and finish and sound.

About the Designer:
Rasmus is a computer scientist and amateur choral singer living in the San Francisco Bay Area. He grew up in Denmark (where all those sweet speaker drivers come from).

Project Parts List:

Designer:
Warren Peace

Project Category:
Bookshelf Speakers

Project Level:
Beginner

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
This is my take on an antique radio using a Dayton KAB-230 amplifier board, an Echo Dot and Overnight Sensation 2-way speaker.

Design Goals:
I wanted to upgrade the sound of my Echo Dots to listen to Spotify Premium. The regular Echo sound better, but just don’t cut it. I like the look of antique radios instead of the plastic things made today.

Driver Selection:
275-030 Dayton Audio ND20FA-6 3/4″ Neodymium Dome Tweeter
297-429 HiVi B4N 4″ Aluminum Midbass Round Frame
My selection for drivers was easy since I just used the Overnight Sensation (OS) design.

Enclosure Design:
The speaker box portion was easy too since I just used the OS plans. Creating the enclosure for the amp, power supply, and Echo Dot took a bit more planning. I used Sketchup to design the radio. I used an antique radio dial frame from a General radio I found on eBay. It took some searching to find one the right size to house the Echo.

Enclosure Assembly:
Assembly was pretty straightforward woodworking.

I used oak wood. I created false inlay with a rotary tool and a homemade jig to carve grooves into the sides. I then stained the rows I wanted darker.

The 3/4″ oak was too thick to install the potentiometers, so I routed it to be thinner where I placed them. The left pot is just being used as a switch, not a variable knob.

The Echo is held in place with friction. I lined the hole with gasket tape and pressed it into place. Took a few tries and some wax paper to let me slip it in, but It finally made it in and won’t go anywhere without a lot of effort.

I used some brass fidget spinner parts for feet. (Finally, those spinners find a useful role on this planet) The old antique radios didn’t have brass feet, but this is my take on the radio, so I felt I had some artistic license.

The grill cover is a bit simpler than the old radios too. I didn’t want anything other than the speaker cloth in front of the drivers.

Crossover Design:

I used the crossover designed by Paul Carmody for the OS speakers.

Conclusion:
I am happy with how it turned out. Now I am working on the left channel speaker. It will be another Overnight Sensation made from oak with the same design elements, but it will be a regular OS size since It won’t house anything other than the drivers and crossover.

Previously, I built a retro video game console from a Raspberry Pi 3 for my boys. This laid an egg in my brain, and I think my next project will be a Raspberry Pi with touchscreen in a sound bar. I am leaning toward two Quark speaker and a Voxel subwoofer all housed in the sound bar. I think it’ll end up being a smart-radio/alarm clock.

About the Designer:
I am a communication strategy Marine Corps gunnery sergeant. I teach public communication at the Defense Information School.

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.

Project Parts List:

Designer:
Bigberts

Project Category:
Freestyle Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
DIY Speaker dock with a recessed to hold an Echo dot, full range speakers and Topping T-amp with USB DAC.

All the cables are hidden in a compartment inside the dock with special slot to hold the Topping T-amp. The amp allows me to switch between My PC, the Echo Dot. The Dot runs at full volume with the amp providing

Design Goals:
Provide better sound for my office.

Driver Selection:
Dayton Audio DW3-1053SC 3″ Full Range Driver
Part # 264-880

Enclosure Design:
Basic sealed enclosure sufficiently sized for Dayton Audio DW3-1053SC 3″ Full Range Driver.

Enclosure Assembly:
Rounded cabinet edges and Duratex finish over MDF.

Crossover Design:
No crossover – using full range 3″ speakers

Tips & Tricks:
Some planning and measurement are needed to recess the Echo Dot

Conclusion:
Satisfactory sound in a compact speaker, This design could be adapted to any small full range/ 2-way speaker design using amplifier board or small amplifier. The Echo Dot provides Bluetooth connectivity and volume control if needed.

About the Designer:
I am an Chemical Engineer in Houston TX and have been dabbling with speaker building for the last 5 years.

Project Parts List:

Designer:
Flipflopforager

Project Category:
Bookshelf Speakers

Project Level:
Beginner

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Stormtroopers, as dubbed by my wife. This was a learning project in terms of design and build.

Design Goals:
Flat response with extended flat bass response and managing to amke the Peerless tweeter work with the Aurum Cantus woofer. Largish bookshelf was the goal with transparency, soundstage, and efficiency.

Driver Selection:
Aurum Cantus 8 ohm 7″ woofer
Peerless Dual concentric 4 ohm tweeter
2″ port with flare

Enclosure Design:
MDF 1.7 L modeled on iOS exclusively
XO is 3rd order butterworth, zobel on both drivers at 8/4 ohms respectively, and attenuation network (Variable L-Pad) on the tweeter. Over engineered the copper wire at 10-12 AWG internally and externally.

Enclosure Assembly:
Surface mount only, time ran out and wanted it done. Flush mount on future builds.

Crossover Design:
3rd order buttersworth, zobel on both drivers, L-Pad on tweeters

Conclusion:
There is better than anticipated off axis response, high efficiency, clean soundstage, transparency with DAC supplied music, warm lovely vinyl music, very good background music experience, some challenges with near off axis and port leakage, latter now resolved with stuffing.

About the Designer:
Just a geek in all things that interest me.

Project Parts List:

Designer:
GKT Design Co.

Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
24″ Bluetooth with rechargeable battery.

Design Goals:
This is my 3rd project and with each one I continue to apply lessons learned from the previous version(s). I also wanted a more finished look with this one and added the grill. The grill ultimately gives me more options for color combinations. With each revision I’m trying to get where I can duplicate and make them efficiently. Ultimately offer these for sale at a “reasonable” price and good quality and style.

Driver Selection:
(2) HiVi B3N 3″ Aluminum Driver Round Frame.

(2) 1TD2-8 1″ Designer Dome Tweeter 8 Ohm.

Enclosure Design:
24″L x 5.5″W x 6.5″H Oak.

Enclosure Assembly:
Basic butt joints and a lot of finesse

Crossover Design:
Only a high pass.

Tips & Tricks:
1: I say it each and every time. Be careful with your space for the electronics. I have run out of room on EACH of these and had to fine a work around.

2: Use a fortsner bit or other to hollow out the wood in front of the bluetooth board. Or, create some openings. Does wonders for range.

Conclusion:
Turned out well and I think the next version will quality enough to offer it up for sale and hopefully someone out there wants to buy it LOL.

About the Designer:
Commercial lighting contractor by day, wanna-be designer, home renovator, and wood worker on the weekends. Located in Dallas, TX.

Project Parts List:

Designer:
David Hall

Project Category:
Bookshelf Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Curly Maple Mini Bookshelf Speakers with Accent

Design Goals:
• Accurate and clean sound reproduction
• Extended low end despite the small size of the enclosure
• Small enough to fit on a narrow shelf
• Visually appealing (if not eye-catching)

While sitting in my office one day, in between jobs, it occurred to me how ironic is was that I had no permanent speakers in my office for listening for my listening pleaseure. I spend the majority of my time in my small office designing speakers when not in the shop fabricating, finishing or assembling speakers. Space is at a premium. There is barely enough room for my desk, electronic bench, file cabinet and a wall covered with books, and not much else. I checked my inventory to see what I had on hand to work with and a few days later music filled my office.

Write up:

curlymaplespeakerproduct_writeup

Driver Selection:
The focus of the design was to design and build small two-way speakers having a supportive low frequency response despite its modest size. I am a fan of the ND series of drivers has they typically have larger than typical excursion as well as good power handling capability for their size. For this build I chose the ND105-8 (290-214). It provides more than adequate frequency response in the lower end given is size and mass. Their look is clean and simple allowing the cabinet’s design to pop.

For the high end, I used the Peerless XT25SC90-04 (264-1014), featuring a 22 mm voice coil mounted in a neodymium motor. This is a good choice for many 2-way speaker applications. It has relatively good off-axis response producing a bright sounding high end without being harsh. Despite its modest price and looks, it handles a lot of power (100 watts rms). The only real detractor are the solder tabs. They are molded into the plastic body requiring you to be fast at soldering because the tabs and the surrounding plastic will melt if disconnect crimps are not used.

Enclosure Design:
The enclosure design is relatively simple as it required no complex baffling. The four sides were fabricated with solid cherry wood. The front baffle is made of curly maple with an added accent stripe made of some exotic strips of wood I had laying around the shop. The back panel is stained 3/16” plywood to accommodate the 1” port and terminal cup.

The inner chamber dimensions are 12 1/4” x 7 5/8” x 4 3/4” for a volume of ~0.235 ft3. The port dimensions are 1” diameter x 4”. This configuration yielded an Fb of 44.8 Hz, further boosting the low end.

Enclosure Assembly:
The front baffles were fabricated from a solid piece of curly maple. These were then bisected at random angles on the table saw. Thin strips of Movingui, African Padauk, and Wenge were laminated together to serve as an accent stripe on the front baffle. The accent piece was then glued between the two maple pieces of each front baffle. Since I compromised the strength of the baffle with the accent stripe, it was glued to a 1/4” piece of maple for structural support. This additional layer was thankfully hidden by the large rubber surround of the speaker. Holes for the drivers was cut using a router and a circle cutting jig and the edges of the woofer holes where chamfered with using a chamfer bit.

The corner joints are miter joints for visual appeal. To accommodate for wood expansion, the front baffle is about 1/8” undersize with the edges rounded over to visually minimize the gap between the front baffle and the edges of the enclosure. The front baffle is secured to the enclosure using silicon caulking rather than wood glue, again to accommodate the movement from wood expansion in the humid months.

Because the miter joint is an end-grain joint, ½” gussets running the length of the joint were glued to the interior of each joint providing strength/rigidity to an otherwise questionable joint. An alternative could have been to use remaining accent stripping for splines in the joint itself (but that would have required building another jig for the table saw and more time).

The finish is a sprayed gloss polyurethane, 3 layers.

Crossover Design:
The tweeter uses a 3rd-order Butterworth filter design while the woofer used a 2nd order Butterworth. Both drivers require some equalization in order to achieve a somewhat flat response. The tweeter’s higher frequencies tend to increase in volume as seen in the frequency response graph below. Thankfully, those frequencies tend to become in audible as they increase. Still an L-Pad was required to tame tweeter down and flatten the frequency response a bit. The ND105-8 had a sharp peak in the frequency spectrum at about 3200 Hz requiring equalization to flatten it out as well.

Tips & Tricks:
Take your time when making miter joints. Everything must be perfect and orthogonal in order to avoid any external gaps in the joint. To accomplish this, I used an Incra Miter1000se miter gauge with telescoping fence to maintain perfect registration during cutting operations.

Butt joints are quicker, easier and stronger, but look cheap so that was not an option. Another joinery option still appealing and very strong are finger joints, but again that would require more time and material to make a fixture for cutting the fingers of the joint.

To cut clean and centered holes for the drivers in any speaker I highly recommend using a Jasper 200J Model 200 circle cutting jig for plunge router. Warning, the 200J is a very delicate piece of thin plastic mounted to a relatively heavy router. Because of all the registration holes in the fixture it WILL snap in two if you’re not careful setting it down. When setting the router down after cutting a hole, make sure the router end of the two, not the far of the plastic fixture, contacts the surface first or the jig will snap and you will spend another $40 to replace it.

Conclusion:
The build was fairly straightforward. As with all my designs, they must accurately reproduce sound and look as good as they sound. This one hit on all goals/objectives. The sound reproduction is excellent with a full but not overpowering low end, small footprint, and they are eye-catching.

About the Designer:
David Hall is a custom speaker and home theater designer, and the owner of SounDesign. The favorite part of his job is speaker design and fabrication. His enclosure designs start with sketch pad and pencil. A lot of paper finds its way to the trash can before a design goes to CAD (computer-aided design). He pursues unique cabinet design and drivers that offer his clients both the look and quality of sound they desire. David’s philosophy is audio should be as pleasing to the eye as it is to the ear. It has to look as good as it sounds and it must sound awesome! David focuses on choosing drivers with optimal qualities to achieve the finest sound in order to diminish or avoid the electrical and acoustic challenges of crossover design. He has, in one way or another, been involve with electronics since he graduated from DeVry (decades ago). Music is a major source of enjoyment in his home. In his younger years David was a bass trombonis t in jazz ensembles and sung and played in several venues throughout the southwest. He is a desert rat living in Phoenix, Arizona with his hot wife, Debbie. Occasionally, in the cool months, he enjoys a good cigar and bourbon (when his wife is not around).

Project Parts List:

Designer:
J.J. Elias

Project Category:
Freestyle Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
Under $100

Project Description:
Modeled after a standard size Lawn & Garden battery

Design Goals:
A creative addition to my workplace office to be in the theme of my job as a parts store manager and as a conversation piece with my professional clients. But really it was to have something GOOD to listen to.

Driver Selection:
299-208 HiWave BMR12 Compact 2″ Full-Range Square Speaker 12W 8 Ohm

Enclosure Design:
Sealed box

Enclosure Assembly:
.75 inch MDF (sides and bottom) .375 inch Clear Pine

Crossover Design:
No crossover

Tips & Tricks:
All butt joints so keep those joints tight when gluing. Plenty of quick clamps make things much easier.

Conclusion:
A big sounding little conversation piece with multiple input choices and a small footprint.

About the Designer:
29 year veteran of the music industry (retired) as both an artist and sound engineer. Auto parts manager for the last 11 years and a moonlighting part time radio DJ.

Project Parts List:

Designer:
Tonewood

Project Category:
Freestyle Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Our Jazzspeaker V2 has 2 Drivers and 2 Tweeters, it is designed to sound great, and look great!
With a baffle made out of solid Padauk it is a one of a kind bluetooth speaker!

Design Goals:
– Make a Bluetooth speaker that looks amazing
– It should have plenty of low end (without a sub)
– It should be able to fill a medium sized room with sound

Crossover Design:
It’s a simple Butterworth crossover

Conclusion:
With all boxes checked, I’m really happy with how it turned out!
I’m hoping to build variations of this speaker in different woods!

About the Designer:
Since I’ve build my first speaker about a year ago I’m hooked!
I found my passion and I continue to build more speakers to improve and learn as much as possible!
I’m working hard because I love it, I’m hoping to build speakers for customers in the future and start my own little business!

Project Parts List: