The host (vbox 3.0.2) is configured to use CoreAudio and is providing an "ICH AC97" controller to the guest.
The guest has the vbox guest additions installed (also 3.0.2) and has bound "pci8086,2415" to the "audio810" driver.
The GNOME volume control program shows an "audio810#0 (OSS v4 Audio Mixer)" device and an "Unknown Volume Control 1 (Sun Audio Mixer)" device, but neither of those devices produces any audio output
Thanks for any help!
Chris