I'm reading and trying to understand why would anyone want to use Pulse Audio and I'm failing to understand. I read this https://www.linux.com/news/hardware/drivers/8100-why-you-should-care-about-pulseaudio-and-how-to-start-doing-it, and I'm still not getting a convincing answer. I have a set up, with one sound card. ( I don't need to multiplex sounds from or to several sound cards). I know that all applications are written with different APIs, ALSA, OSS, JACK etc. So if I configure all those frameworks to route the sound through pulse audio, what benefit do I get, vs allowing all those frameworks talking directly to the sound card driver? In addition, I don't see that Pulse Audio has it's own Application API. So I need to choose a framework anyway (like ALSA). Thanks
It's all about multiplexing.
I don't need to multiplex sounds from or to several sound cards
Ah, but you do! If you want to be able to play audio from two sources at once, ever, for any reason, you need multiplexing.
OSX and Windows handle Multiplexing in the Kernel (but still in software), which is why this never/rarely comes up on those platforms.
However, on Linux, with software like ALSA, multiplexing is left up to the specific sound card / implementation / driver.
Unfortunately, not all cards and all drivers actually support this out of the box.
That's where PulseAudio comes in, doing the multiplexing in software, regardless of your sound card / driver situation.
Without this functionality, if you were say, using ALSA directly sans-PulseAudio, with a sound card that had poor PCM multiplexing support on Linux, you would only ever be able to hear sound from one application at a time.
E.g. if you had a video playing in your web browser, and received a notification in Pidgin, you would not hear the notification sound because your web browser would already have control of your sound card.
By routing all sound through PulseAudio first, this problem is avoided.
Source: A long IRC conversation I once had with the Ubuntu maintainer for ALSA, where I asked them the exact same question you're asking now.
Since introduction of Dmix in alsa, pulseaudio turned to be useless. Bare alsa with Dmix somehow enabled deep inside (I haven't have to set anything) works much better for me. For example, there is no delays while a sound level is being changed.
Just uninstall pulseaudio if you are using recent alsa and feel fine.