I have been reviewing the questions related to Kol Isha (including links about parrots, men with feminine voices, radio recordings and Siri singing) but I was asked whether halacha has dealt with voice transposers.
One can buy a technology that can, in real time, modulate a person's voice so that it sounds different (and shifting the pitch can make it sound male or female).
IS the underlying prohibition related to the sound of a woman's voice and the thoughts it can inspire (ignoring the subtlety in opinions related to whether the listener has seen an image of the singer) based in the sound of the voice, or the source of the voice?
Can a woman with a bad singing voice, or a voice shifted to sound male inspire thoughts simply because she, as a source, is still a woman? Or must the voice "sound like" a woman to do its part in triggering the thoughts?