Boombox

Boombox


Designer:
Jay

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
20+ Hours

Project Cost:
$100 – $500

Project Description:
Project began as a simple replacement of a blown bass speaker in a commercial bluetooth speaker (Doss Soundbox).

But then I decided to also replace the other drivers while I was at it. Figured I couldn’t get anything to match the case perfectly, so I decided to make a new case, a BT speaker has been something I’ve wanted to make a long time.

But then I also decided I didn’t care for the controls of the amp, and I wanted to add wifi capability, so I replaced the amp, preamp, controls, and power system as well.

In the end, the only parts remaining from the original speaker are the screws the hold the 2″ drivers to the soundboard.

I was in the middle of another project in the shop, but no music was an emergency that had to be fixed asap.

Design Goals:
I use a small portable speaker a lot; when working from home, when in my shop, when working out, and for dance parties with the kids.

Of course the goal of any speaker project is to look and sound as good as possible within the confines of the budget.

The speaker I was replacing took care of the conceptual design (the piecemeal on the fly design approach ensured it). 2.1 system with 2x 2″ 4 ohm speakers and a 1x 3.5″ 4 ohm speaker and 2x passive radiators.

I really wanted it to have wifi in addition to bluetooth so that there was no single controlling device that had to be nearby and dedicate its audio to it (mainly so I can watch ads while gaming or videos on social media without interrupting the music).

I have a retromodern design aesthetic.

Driver Selection:
1x Peerless SLS-85S25CP04-04 (# 264-1600)
2x Dayton Audio DMA58-4 (# 295-582)
2x Dayton Audio DMA80-PR (# 295-595)

Enclosure Design:
The basic scale is the same as the Soundbox I was replacing with the exception of depth. I moved the passive radiators to the sides and used speaker type passives instead of an oval rubber pad, which doubled the depth needed. Being wood and not plastic, its a good bit thicker.

I used stack laminated baltic birch (strips from some 3/4″ reclaimed pieces I have) and 3/8″ baltic birch sheet. The front and back are from a knarly old cherry board I found at an estate sale, cut quartersawn its figure is fantastic, and the color is so much richer than typical cherry.

The controls area is made from quartersawn figured maple “veneer” (about 1/4″ thick resawn) with a slim cherry border. The back was done similar, though a bit thicker, 5/16″ or so. Quartersawn wood moves much less than other cuts, important for the back to prevent bowing. I applied it bookmatched.

Shaping was done with my carving weapon of choice; angle grider with a flap disk.

Enclosure Assembly:
Lots and lots of Titebond 3. Lots. Huge amounts. Soundboard is screwed down.

Crossover Design:
Channel levels on the 2.1 amp for balancing; it has a built in low pass on the 0.1, not sure exactly what frequency.

Tips & Tricks:
Stack laminated baltic birch is almost as hard as an end grain maple cutting board and power carves excellent (its so hard its quite forgiving). I’ve used it on several projects now (I got a bunch reclaimed from Jaguar car crates years ago.

Ground loop isolator is VERY important to eliminate noise. I had massive hum problems until I added it, noise is minimal now.

Conclusion:
This thing sounds amazing. I added a bit more weight to the radiators, it can really hit low notes for a speaker this size.

Great project. Such a joy to work on and now use.

About the Designer:
Hobby woodworker, general engineer (civil specialty) in the aviation field.

Project Parts List:

Peerless SLS-85S25CP04-04 3-1/2″ Paper Cone Woofer 4 Ohm
Dayton Audio DMA58-4 2″ Dual Magnet Aluminum Cone Full-Range Driver 4 Ohm
Dayton Audio DMA80-PR 3″ DMA Series Passive Radiator

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