On Fri, Jul 15, 2022 at 06:04:49PM +0800, zhaochengyi@xxxxxxxxxxxxx wrote: > Hi guys, > > On a special PC, it is required to start the pulseaudio daemon > with some special parameters in the file /etc/pulse/daemon.conf, > as follows: > > ------- > default-sample-rate = 48000 > default-fragments = 2 > default-fragment-size-msec = 20 > ------- > > When plugging in a USB headset with a separate sound card to this special > PC, > I found that there was a noise in the playback audio. After investigation, > the sound card of the USB headset needs to use the following default > parameters. > > ------- > default-sample-rate = 44100 > default-fragments = 4 > default-fragment-size-msec = 25 > ------- > > So, how to enable the parameters required by the sound card > of the USB headset when using it. Assuming you are using pulseaudio 15.0 or newer, there is a feature to apply module-alsa-card parameters by udev rule. See: https://freedesktop.org/wiki/Software/PulseAudio/Notes/15.0/#index8h3 Just craft an appropriate udev rule that matches your USB headset and include the PULSE_MODARGS variable with rate / fragments / fragment_size set appropriately. Note that fragment_size is in bytes, see the docs for more info: https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Modules/#module-alsa-card --Sean
