Experiments with Hybrid sound body appliances have started by coupling speakers into the sound box of an acoustic instrument. Both sound generation are in theory opposite by its purpose: a speaker box is designed to not resonate with the vibration of the transducer, meanwhile the soundbox of an acoustic instrument is a surface aimed to compress air and forces in a way that the sound could be streamed.
As in archiecture, the "design" of spaces has to offer for each purpose a specific room and environment. The approach was similiar on Knurl: The resonance chamber and the bridge improves acoustic qualities related to reflection, meanwhile the tailpiece receives an internal layer of muffled material to absorve the sound from the speakers. Knurls acoustic system improves the direction of tensioned body, while its electric system deals with release and restraint.
4 speaker of 4 ohm are connect into the bela Board (bela.io). Since bela only handles 8ohm, I connected 2 speakers in series with the others, having then 8 ohm of each channel. Therefore, Knurl is stereo with the possibility to implement a 4 chanel sound system if connect to an amplifier class D.
The speakers in the bridge are disposed in a angle where improves hifi reflections in a stage/concert hall environment. The speakers at the bottom part improves lofi reflections, by its angle adjust towards the floor.