Requenes.com

It has several output options. 1) it can send the corrected signal to an amplifier, as during a live performance. 2) it can convert both the corrected and uncorrected (dry) signals to MIDI (Musical Instrument Device Interface) format and either save them to a file or route them to a synthesizer, which would play the same notes, but with a different voice.

The amount of correction could be adjusted to taste. Since the dry version is stored along side the corrected version, it would be possible to vary the amount of correction dynamically from section to section. Once the music is in MIDI format, it can be edited with popular music composition packages into complex arrangements.

The idea is to allow anyone with the desire and the knack (but not the formal skill) for composing tunes to write and record original music. This follows the pattern of machine facilitating individual creativity. The Music Conditioner is to music as the calculator is to Mathematics and the spell-and-grammar checker is to writing.

I believe similar hardware is already used to clean up popular, though not musically gifted, singers' voices in concert.