Building log of the FM Radio and Bluetooth Bookshelf Speaker Project
FM radio is more popular than ever, but finding a simple radio for the average room that looks good, sounds good and is intuitive to operate, can be challenging.
Instead of compromising on design, quality, sound or usability, a custom speaker was built. Integrated in the speaker is the TIMBERtune Audio Module for the FM Radio and Bluetooth audio streaming functionality.
Any DIY speaker kit can easily be used, but this one was built from scratch to achieve the desired design.
The Specifications
Here are the specs:
- Size: 15.5” wide, 5.7” high and 4.5” deep
- Internal volume: 235 in³ (sealed enclosure)
- Wood: Baltic birch plywood
- Finish: Old Masters Oil-Based Sanding Sealer
- Speaker: 2x Dayton Audio RS100-4 4″ Reference Full-Range Driver 4 Ohm
- Amplifier: 2x30W Infineon MERUS MA12070 based Class D amplifier
- Further hardware:
- Bourns 5k Ohm stereo audio potentiometer with rotary switch for volume control and on/off switch
- Volume knob
- 2.1 mm DC power jack (Barrel Plug 2.1 x 5.5 mm)
- 15 VDC / 800 mA (12 W) AC/DC power adapter
The Speaker enclosure build process
The enclose is build from Baltic birch plywood panels, 3/4” for the walls and 1/2” for the front and back panel. All parts are CNC machine cut:
The walls consist of a 5 piece “stackup” of 3/4” thick parts glued together:
The 1/2” thick front panel is glued on as well, and the back panel is secured with wood screws (to finish the wiring and access the electronics).
The regular finishing process included (lots of) sanding and just one final coat of the sanding sealer for a natural wood look.
The final result
Since that was fun, we made 3 more and used dark brown walnut stain and pink acrylic paint (yes, my daughter loves her radio) on the others:
The material used
(not affiliate links):
- TIMBERtune FM Radio and Bluetooth Audio Module:
https://timbertune.com/ - Dayton Audio RS100-4 4″ Reference Full-Range Driver:
Parts Express - Amplifier:
Own board based on the MA12070 Class D audio amplifier chip - Wood finish:
Old Masters - Hardware: