We want to tie a player piano into a C4 matrix amp. The only other time I did this, the piano retailer provided & installed everything that was needed. It's my understanding that all we need is a pickup and a mixer to combine the feed from the pickup and the accompanying audio.

We're looking at the Fishman SBT-HP pickup. Anybody have experience with this kind of integration? And can someone recommend a simple small-form-factor mixer that would lend itself to mounting underneath a piano? Thanks in advance.