In my experience, most of the problems people have with PulseAudio come down to buggy ALSA drivers not handling buffer resizing correctly. Adding tsched=0 as a

In my experience, most of the problems people have with PulseAudio come down to buggy ALSA drivers not handling buffer resizing correctly. Adding tsched=0 as a module option "fixes" that by making them not export the buggy interfaces. The result is much the same as playing directly through ALSA. The reason PulseAudio wants to use these interfaces is that it has to make a tradeoff between CPU utilization+battery usage versus low latency. If you use ALSA directly, the first application to open the device controls the size of your buffer. The first client was a music player requesting a large buffer? Then your SIP client will get high-latency audio. PulseAudio tries to fix this by dynamically resizing the buffer. I'm sure there's actual issues with PulseAudio, but somehow most of the problems I see people complain about lie further down the stack. Of course, discussion of pulseaudio is rather off-topic here, it was just one more example of how "just shut down the new thing!" is often easier than diagnosing the actual problem.