Can I use my instrument with a TC Helicon Processor?
As all of our products are developed and tailored to use with the human voice, we don't directly support the use of other instruments through our device - that being said many people have used our devices with success on various brass and other monophonic instruments. You could use a polyphonic instrument, just keep in mind effects like Harmony, Doubling, HardTune and Pitch Correction will only work properly if playing single notes (monophonic).
Also, you should be aware that some of the pitch-shifting algorithms (depending on the product) rely of the human voice as input, and may not work as intended when used with instruments.
All effects are applied to the mic input on our devices (the Voicelive 2 and Voicelive Rack also have line inputs) so you would need to mic up any instruments you plan on plugging in - Seems like the Harmony G XT, Voicelive 2 and Voicelive Play are all products people have used with success, but most of them should work with various wind instruments – for sure you should try out the model you wish to purchase with your instrument to be sure it will suit your needs.
There are a few threads on our (old) user-to-user forum from people using our products with wind instruments: