I've been very pleased with the results from my MUSICTECH wireless system for my acoustic /midi accordion .it transmits and receives and also supplies power for the midi in the actual accordion .Tthe receiver output is connected to the midi in on my expander module . the stereo out of my midi accordion is from the stereo outlets on the expander .
The acoustic side of the accordion is picked up from my sennheiser headband mic and is very effective and also goes thro my expander via the mic input !!!
This set up allows me complete freedom of movement on stage etc and allows me to stroll as well !! with no trailing wires/cables etc
Take a look at the musictech web site www.musictech.it


regards ......Giovanni