Pitch to midi guitar systems have been around since the mid 80s. If the OP only needs control data, there's no need to bring a dedicated computer and multiple channel sound card into the equation. I use a
Shadow SH-075 which was built in W. Germany (!) in the late 80's I bought off of eBay and it's tracking speed is definitely acceptable, at least for what I do. There is a new guy on the block, the
Fishman Tripleplay which I'd like to upgrade to as it's standard USB midi so will work with PdParty and my iPad. Both of these are relatively small as compared the Roland's rack mount and stomp box offerings (why don't they shrink the GR stuff by now?).
Just saying that not every nail needs the PD hammer. Forgive me if my understanding of the original question was wrong.
Subject: Re: [PD] midi question
Date: March 12, 2014 at 9:00:47 AM EDT
You could also get a sound card with 6 analog inputs and connect each output of the microphone to an individual channel. This way you can do 6 at a time.
--------
Dan Wilcox
@danomatika