SightReadingFactory.com

It would be incredibly helpful to be able to set up an assignment as "Choir (multi-part)" and be able to indicate what voice part you sing.  That voice part would then be muted while the other parts played, giving a sense of what sight reading in a choir is really like.  This would allow students to practice in a "music minus one" format, typical of many audition settings.

Yes! This is a fantastic idea. Most of my students have this kind of sight-singing in their auditions and this would be most helpful. 

Here here

Yes, please!! :)