[Overtonwindow]

Nope. They absolutely cannot be delayed auditory feedback. That disrupts speech. The device must reproduce the chorus effect. [0]

[0] https://www.youtube.com/watch?v=Xw_rVGUXgos

[vigliag]

Some of those DAF apps can also apply pitch shifting (which is actually AAF). Provided they work properly, they should be able to provide that choral effect. I am no expert by the way, I've only toyed with those for a few minutes.