Just exactly what we needed. Well Constructed.
This acoustic driver works great with a wide range of passive pickup instruments. It seems to be extremely well constructed and engineered for the price. I initially bought it to amplify a banjo but have since used it for a mandolin and a bouzouki. It allows you to not only amplify the signal but to also adjust the sound to replicate the natural sound of the instrument. I have a Fishman that I originally bought to use and paid over twice as much for and it holds no comparison what so ever to the ADI21. I recommend it highly and several of my friends have purchased this driver after hearing it.