Project Category:
Portable Speakers

Project Level:
Beginner

Project Time:
1-8 Hours

Project Cost:
$100 – $500

Project Description:
Some what portable, easy to use and respectable sounding bluetooth speaker.

Design Goals:
Essentially what I wanted was a somewhat portable, good sounding bluetooth speaker with a long battery life that I could bring to BBQ’s and camping trips to introduce my friends to what good sound actually sounds like. I originally wanted to go with an ammo can speaker but after consideration I realized it just wasn’t possible to produce good sound without a lot of extra work.

Driver Selection:
I went with the Tang Band W3-315E just because I had them laying around from a past project. They aren’t sold anymore but the W3-881SJF are comparable.

Enclosure Design:
I’m not an expert wood worker so I kept the design simple. I chose birch wood that was already 7.25″ wide (.75″ thick) off the shelf so all I had to do was cut the lengths for each piece.

External Dimensions:

11″ W x 7″ H x 8.5″ D

Top/Bottom:

7.25″ x 11″

Sides:

7.25″ x 5.75″

Front/Back

7.25″ x 11″

Basspro6 recommend and enclosure of 0.198ft^3 but the actual box is 0.21ft^3 to compensate for the displacement of the bluetooth board, batteries and drivers. The port is 2.6″ long and 1.5″ in diameter for a fb of 75hz.

Enclosure Assembly:
The enclosure assembly is fairly straight forward. Use wood glue and glue the top/bottom and sides together at 90 degree angles followed by the front. I designed the back of the speaker enclosure to be removable. I used 2.5″ pocket screws to secure the back panel and 3/8″ wide speaker gasket to seal the panel.

I sanded everything with a palm sander starting with 60 grit and worked my way up to 220 grit. I did one coat of pre-stain conditioner followed by one coat red mahogany stain and three coats of polyurethane gloss.

On the back panel I used a simple power switch, 2.5mm female power jack and flush mounted the 3 LEDS for the bluetooth board.

Crossover Design:
Didn’t use one. You could use a knotch filter to tame the peak around 10khz but its not necessary in my opinion.

Tips & Tricks:
Take your time, sand, sand, and then sand some more.

Conclusion:
Overall i’m extremely pleased with this project. The speaker sounds great, battery life is around 7 hours and it looks great in my opinion. The sound is much bigger then the speaker itself, vocals are rich and overall very pleasant to listen to. They’re not “audiophile” grade but hands down better than any off the shelf bluetooth speaker.

About the Designer:
I’m an aviation electronics technician with 6 years of experience working on the AV8-B Harrier with a small hobby of building speakers.

Project Parts List: