The TC Helicon MIDI controllable harmonizers (see list of products below)) require a MIDI connection from your keyboard. USB is a computer interface, which can't be "converted" into MIDI by way of an adapter.
Generally speaking, TC Helicon can't recommend using keyboards with only USB connectors available, as these are usually either designed for home-use or for only connecting to a computer. When picking a keyboard, we can recommend picking one with MIDI connectors instead, which enables the keyboard to integrate with most studio / live-units on the market today.
That said, it may be possible to connect the keyboard via USB to the computer, buy a separate USB MIDI interface, and configure your computer host program / MIDI setup to retransmit the key changes on the keyboard via the MIDI output to the harmonizer (though obviously in this example the keyboard is still not connected directly to the harmonizer as the computer is required to "translate" between the two). We're not aware of any devices on the market today capable of handling the computer's role, in this example.
This FAQ concerns the following products:
- VoiceTone Harmony-M
- VoiceLive 2 / VoiceLive 2 Extreme Ed.
- VoiceLive Touch
- VoiceWorks Plus
- Quintet (discontinued)
- VoiceLive (discontinued)
- VoiceOne (discontinued)
- VoicePrism (discontinued)
- VoicePrismPlus (discontinued)
- VoicePro (discontinued)