When my system gets to suspension while the song being played, and got resumed from the suspension, I found my Rhythmbox player running but no sound coming even from the system. I had to suspend it and press the power button to get the sound back. Why is it happening so?
Try turning off your sound device (click on volume control, click sound preferences, and then go the hardware tab, click the device, and choose off).
Then press alt+f2, and type
What worked for me was asking pulseaudio to exit:
This causes the audio device not to be in use anymore. Then I reloaded the module for my sound card:
Finally, I restarted pulseaudio:
I also re-uploaded the sample I was using for the bell sound. Unfortunately, any applications which had connected to the old instance of PulseAudio had to be reinitialized somehow (for example, a Web browser with a YouTube video had to have their page reloaded). It's a pain in the behind, but at least it's repeatable, and so far always works. I have this in a shell script so that it's easy to do after resuming from suspend. The biggest hurdle may be figuring out your sound card's driver.
This happens to be for an HP Pavillion a1257c with an Aureal Vortex PCI sound card. This same sound card in a Precision 670 had no problems coming back from suspend, same OS, so it would seem to me to be definitely specific combinations of hardware which can cause difficulty.