To improve the sound of Hardkernel’s Stereo Boom Bonnet (https://goo.gl/TrDU8u), I went to my local hobby shop and got an “assortment pack” of styrene which happened to have some .080mil sheets and some tubing in it. I also purchased a little styrene solvent for welding. I did everything by eye, so some of the corners are not square, but this is intended to go into another cabinet, with only the face plate showing through. When it's complete, I'll glue a piece of cloth over the front and remount the speaker with hex head screws exposed. The boxes will be for acoustics and vibration control. If I were to make the boom box a standalone cabinet, I would probably make it about half as deep, but I chose this size because of the depth of the housing cabinet. I don't think there would be much sound difference with a longer tube.
One thing not shown in the pictures is shredded cotton balls. When the project is complete, I'll have the wires extend to a connector on the back, and the entire box will be loosely stuffed with pulled cotton to make a baffle, in order to prevent a “hollow box” sound.
I am deliberately leaving out measurements, since they don't matter much. I think it would be better to replace the tube with a simple flat sheet spaced up from the bottom about a quarter diameter of the speaker and spaced from the back about the same length. You can find designs all over the Internet for various chamber designs and ideas if you want to go more in-depth.
Do something like this with any speaker, including the Stereo Boom Bonnet, and it will instantly sound better. To experiment with the sound, I inserted the front panel in backwards since I haven't extended the wires yet, and the sound was amazing. It tries to do a little bass, not much below 100Hz,but if I put my finger over the tube most of the bass goes away, so the chamber appears to be working like it should. Once the wires are extended out the back and the tube is in the box properly, it should give a tiny bit more bass.
For comments, questions and suggestions, please visit the original post at https://goo.gl/yyp22n.