This is a mute system for the trumpet and cornet. Can be used as 1- a passive mute (seal all the holes at the bottom to the outside apart from the pipe output). 2- Electronic mute, place a condenser microphone at top, put a small amplifier circuit inside and a voltage boost circuit for converting 1.5V dc to the required voltage for the amplifier. here is my voltage converter http://www.ebay.com/itm/DC-DC-Boost-Converter-Step-Up-Module-1-5V-to-5V-500mA-for-phone-MP4-MP3-Arduino-/351390823155?pt=LH_DefaultDomain_0&hash=item51d08672f3 I've ordered these but not tested yet for the microphone amplification http://www.ebay.com/itm/1pcs-Microphone-MIC-amplifier-module-Voice-Module-NEW-/201226168458?pt=LH_DefaultDomain_0&hash=item2eda03a88a I've made a prototype with the circuit schematic above. It works, but could be better. For obtaining a proper reducement in the sound passing thru the mute, all holes must be sealed from inside with something like a glue etc. Only the pipe output should stay open. If you have recommendations about the project, circuit schematics etc., post comments please.