Comment 5 for bug 1605797

Thank you Raymond for looking into this.

Another thing that may be helpful: I removed a working vdi with Ubuntu guest o/s (version 15.XXX) running on the same host (current OS X).

In that guest, which also ran in VirtualBox, I had no problems with sound at all & I had installed a few other softwares (Audacity, some python tools,etc.).

In the new guest, the only non-standard software is Ardour4 and there is no difference between the sound ability now and prior to installing that.