I keep noticing in forum comments that many people using Linux seem to hate Pulseaudio, the default audio subsystem in most modern Linux distributions. I seem to be in the minority with my sentiment toward it, but I actually think Pulseaudio has been the best thing to happen to audio in Linux in a long time. Before Pulseaudio, I was always having problems with one program grabbing the audio device and other programs not being able to play sounds. How stupid is that? I know that there is some kind of mixer plugin for ALSA, but it was hardly ever working or set up on distributions I tried before Pulseaudio was adopted. Pulseaudio finally provided a sane way to share audio devices and mix audio streams so several programs could have access to audio at the same time, including the ability to set audio levels for each program separately.
I agree that Pulseaudio was badly implemented in some distros when it was first adopted, and it may have been adopted before it was ready for prime time. That may have contributed to the bad reputation it seems to have. But I can completely understand that distro makers were eager to adopt it as it solved a real, glaring problem with audio in Linux. Even in its half-baked state at the time, it was an improvement over the status quo. And lately, I have had zero problems with it. It works great and does exactly what it needs to do.
One common problem I've heard mentioned and experienced myself has been: "With Pulseaudio I have no sound, and if I get rid of it, sound is back". What has been my experience is that this problem has nothing to do with Pulseaudio, but with ALSA being set up incorrectly by the distribution. Pulseaudio sits on top of ALSA, and on several installs I have seen the problem that the master volume for ALSA is set to zero by default. So, there is no sound coming from the speakers, even if Pulseaudio is doing its job just fine. The solution is to use 'alsamixer' to make sure the ALSA volume levels for master and PCM are not set to zero and then use 'alsactl store' to save the new levels to make them persistent (all of this as user 'root', or using 'sudo' to gain administrative privileges).
I think the reason removing Pulseaudio makes audio work again in this case is that the desktop volume control only controls Pulseaudio's volume, if Pulseaudio is in use. So to the user, it looks like the volume is up, but on a lower level, invisible to the user, it is all the way down. Now when you remove Pulseaudio, the desktop volume control gets tied to ALSA's master volume intead, and so it can now be used to fix the zero volume problem, and things work. This leads to the incorrect conclusion that Pulseaudio was the problem, while in reality it was ALSA that wasn't set up correctly.