After playing MobFobAmp for a while, I wanted to take another step in the evolution towards a really good portable instrument combo. With this design I’m trying to address the shortcomings of the previous prototypes:

  • Power output could be higher
  • More volume in the low lows would be nice
  • Folding mechanism a bit fiddly.
  • I’d like a one-step unfold, preferably one-handed operation possible
  • Mechanical stability and robustness could be improved
  • Sensitive components mounted on the outside requiring to be handled with care

A first design#

Taking the above points into account, I figured out that I had to compromise foldability a bit to get all the sensitive components including the speaker chassis to the inside of the cabinet. A ball-shaped design would be ideal for best low frequency / size ratio, but I didn’t know how to manufacture such a design - so I went with a cylindrical approach. I’d like the speaker to “pop up” so it would be protected from mechanical damage when folded. So my first idea looks like this:

Shelly13 scetch

Project constraints#

I cannot manufacture the cylinders myself so I’d have to contact a drums manufacturer to send some unfinished custom-size Tom-toms over to me. Even if I get those, I’ll have to cut on a curved surface which I never did before, and I’d require some 3D printing / routing to craft an adaptor plate between speaker and cylinder… Or will I just have the speaker mounted on the top/bottom? Plus, I’d have to think about how to include a more powerful amplifier into my design - there are some ideas like this Pioneer car amp or the specialized Hi-Fi amp from DIY Class D but they have very different and maybe harsh requirements on power supply…

Conclusion#

You see, many open items to think about. I’ll let this sink in for some time before continuing work on this project.