I am having issues with sound on my son's computer. We are unable to run two sound applications simultaneously. Occasionally, I can stumble upon a combination of more than one (usually two) that will work together. But, it's not repeatable.
I have tried a few combinations non of which worked together, such as Skype and Pandora, Pandora and Movie Player (which I guess is Totem), Pandora and VLC. Oddly, even video would not play on Movie Player while another sound application was open, but VLC video would play (without sound). I did not try every combination because I just didn't have time. If you think it would be beneficial, I can go back and do so. I don't know enough about the backend sound systems that these applications use to interpret which combinations, if any, would be significant in terms of troubleshooting.
Often times, you would not want two sound apps open at the same time. But, in this case, my son plays Minecraft and talks on Skype. So, it makes sense in that case. It seems that whichever one he starts first gets control of the sound output and the other app can't get any output.
He is using Debian Wheezy AMD64. He is using Gnome 3 as the desktop. He is running Pulseaudio. His motherboard is an Asus P8Z68 Deluxe and proc is i7. He has a logitech webcam for input. But, that hasn't been an issue. I only mention it to explain the USB-Audio below.
I've been using Debian and Linux for many years. But, I've never been able to wrap my head around sound problems (which I seem to have with every new install). I get confused by alas, esd, pulseaudio and so on. Sound issues have always been hit or miss for me, with something sooner or later just ending up working. I'm not sure how to troubleshoot this. Any suggestions would be greatly appreciated.
$ cat /proc/asound/cards
0 [PCH ]: HDA-Intel - HDA Intel PCH
HDA Intel PCH at 0xfae20000 irq 74
1 [U0x46d0x821 ]: USB-Audio - USB Device 0x46d:0x821
USB Device 0x46d:0x821 at usb-0000:00:1d.0-1.4, high speed
2 [NVidia ]: HDA-Intel - HDA NVidia
HDA NVidia at 0xfa080000 irq 17