What is quantum computing going to mean for digital audio/music?
Just more power in a smaller package (which though lends itself well for improving real-time audio, which, as you may have noticed, is quite of a resource hog even in today's standards). Quantum computing is mainly a computer technology topic and one of its major motivations is to extend Moore's law to even smaller devices with less power consumption and more power. There's no suggestion that quantum computing would seem any way different to a computer user, eventhough the technology opens up to certain interesting topics (and applications) in how computing is done or what quantum computing can be used to do (as opposed to the current computer architectures), it's just different "under the hood".
Maybe more precise FFT resynthesis?
https://www.eurekalert.org/pub_releases/2017-03/qmuo-qpo031317.php This reference "describes for the first time the use of the Filter Diagonalisation Method (FDM) in music signal processing. The technique has origins in quantum physics and is employed to study molecular dynamics and nuclear magnetic resonance."
I begin to imagine how quantum phenomena could represent music generated by a quantum computer..