Sound crackle when new sound is played while other sound already plays

klement · 2015-01-27 16:21:13

Hi all,

I am using audacious as my media player and noticed that whenever firefox plays notification sound for gmail chat, I hear a short unpleasant crackling.
Hunting around I found out that gnome-music has the same issue - if I have audacious playing a song and start playing a song in gnome-music, I hear the same crackle, if I change the song in gnome-music, again, crackle.
Interestingly, if I leave gnome-music playing a song and change the songs in audacious, no crackle. (That might indicate that audacious does not end one sound stream and start another when changing the song).

I tried changing the scheduler by adding tsched=0 to pulseaudio config and restarting the PA server.
I tried changing the default-sample-rate to 48000.
I tried changing resample-method to speex-float-0.

This happens with builtin Intel sound through one-link dock but it also happens with my USB DAC so it seems that h/w is not the culprit here. The USB DAC worked perfectly fine on a different laptop a few days ago running Fedora so I am confident it works fine.

Any idea what I should try next?

My daemon.conf has all options commented out now except exit-idle-time=0

/etc/pulse/default.pa looks like this

#!/usr/bin/pulseaudio -nF
#
# This file is part of PulseAudio.
#
# PulseAudio is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# PulseAudio is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with PulseAudio; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

# This startup script is used only if PulseAudio is started per-user
# (i.e. not in system mode)

.nofail

### Load something into the sample cache
#load-sample-lazy x11-bell /usr/share/sounds/gtk-events/activate.wav
#load-sample-lazy pulse-hotplug /usr/share/sounds/startup3.wav
#load-sample-lazy pulse-coldplug /usr/share/sounds/startup3.wav
#load-sample-lazy pulse-access /usr/share/sounds/generic.wav

.fail

### Automatically restore the volume of streams and devices
load-module module-device-restore
load-module module-stream-restore
load-module module-card-restore

### Automatically augment property information from .desktop files
### stored in /usr/share/application
load-module module-augment-properties

### Should be after module-*-restore but before module-*-detect
load-module module-switch-on-port-available

### Load audio drivers statically
### (it's probably better to not load these drivers manually, but instead
### use module-udev-detect -- see below -- for doing this automatically)
#load-module module-alsa-sink
#load-module module-alsa-source device=hw:1,0
#load-module module-oss device="/dev/dsp" sink_name=output source_name=input
#load-module module-oss-mmap device="/dev/dsp" sink_name=output source_name=input
#load-module module-null-sink
#load-module module-pipe-sink

### Automatically load driver modules depending on the hardware available
.ifexists module-udev-detect.so
load-module module-udev-detect
.else
### Use the static hardware detection module (for systems that lack udev support)
load-module module-detect
.endif

### Automatically connect sink and source if JACK server is present
.ifexists module-jackdbus-detect.so
.nofail
load-module module-jackdbus-detect channels=2
.fail
.endif

### Automatically load driver modules for Bluetooth hardware
.ifexists module-bluetooth-policy.so
load-module module-bluetooth-policy
.endif

.ifexists module-bluetooth-discover.so
load-module module-bluetooth-discover
.endif

### Load several protocols
.ifexists module-esound-protocol-unix.so
load-module module-esound-protocol-unix
.endif
load-module module-native-protocol-unix

### Network access (may be configured with paprefs, so leave this commented
### here if you plan to use paprefs)
#load-module module-esound-protocol-tcp
#load-module module-native-protocol-tcp
#load-module module-zeroconf-publish

### Load the RTP receiver module (also configured via paprefs, see above)
#load-module module-rtp-recv

### Load the RTP sender module (also configured via paprefs, see above)
#load-module module-null-sink sink_name=rtp format=s16be channels=2 rate=44100 sink_properties="device.description='RTP Multicast Sink'"
#load-module module-rtp-send source=rtp.monitor

### Load additional modules from GConf settings. This can be configured with the paprefs tool.
### Please keep in mind that the modules configured by paprefs might conflict with manually
### loaded modules.
.ifexists module-gconf.so
.nofail
load-module module-gconf
.fail
.endif

### Automatically restore the default sink/source when changed by the user
### during runtime
### NOTE: This should be loaded as early as possible so that subsequent modules
### that look up the default sink/source get the right value
load-module module-default-device-restore

### Automatically move streams to the default sink if the sink they are
### connected to dies, similar for sources
load-module module-rescue-streams

### Make sure we always have a sink around, even if it is a null sink.
load-module module-always-sink

### Honour intended role device property
load-module module-intended-roles

### Automatically suspend sinks/sources that become idle for too long
load-module module-suspend-on-idle

### If autoexit on idle is enabled we want to make sure we only quit
### when no local session needs us anymore.
.ifexists module-console-kit.so
load-module module-console-kit
.endif
.ifexists module-systemd-login.so
load-module module-systemd-login
.endif

### Enable positioned event sounds
load-module module-position-event-sounds

### Cork music/video streams when a phone stream is active
load-module module-role-cork

### Modules to allow autoloading of filters (such as echo cancellation)
### on demand. module-filter-heuristics tries to determine what filters
### make sense, and module-filter-apply does the heavy-lifting of
### loading modules and rerouting streams.
load-module module-filter-heuristics
load-module module-filter-apply

# X11 modules should not be started from default.pa so that one daemon
# can be shared by multiple sessions.

### Load X11 bell module
#load-module module-x11-bell sample=bell-windowing-system

### Register ourselves in the X11 session manager
#load-module module-x11-xsmp

### Publish connection data in the X11 root window
#.ifexists module-x11-publish.so
#.nofail
#load-module module-x11-publish
#.fail
#.endif

### Make some devices default
#set-default-sink output
#set-default-source input

Thanks for any help.
Klement

Last edited by klement (2015-01-28 14:03:22)

ewaller · 2015-01-27 17:11:54

Hi Klement,
Welcome to Arch Linux. Could I get you to edit your post to use BBCode code tags around file contents and program output? Your readers will appreciate it. It is also our policy

The link is also available under every message post and reply box on the forums.

Are you using Pulseaudio?

klement · 2015-01-28 14:04:44

edited the post for clarification.

yes, I am using pulseaudio

ewaller · 2015-01-28 15:55:44

You may want to install pavucontrol. Run that program and pull up the output devices tab. Try to play audio and ensure that the audio source pops up in pavucontrol and that the audio level indicator bounces to the music.

Also, what do you mean by crackle? Do you hear only a crackle with no intelligible audio? Or do you hear what you expect except that it is polluted with noise?

klement · 2015-01-28 16:21:35

I have pavucontrol and I see the audio sources appearing when playback starts.

When I have one audio source playing and I start another, for a fraction of second the sound skips and cracks as if part of the sound buffer got corrupted.

EDIT: I just realized another thing : I have the same setup: I start audacious, push play, music plays, then I start gnome-music, push play, hear skip/corruption/crackle. Now the gnome-music plays the song, I pause the song and realize the volume of audio stream from audacious went down. When I close gnome-music, it gets restored again. I am not sure whether this could be the cause. Also I this probably shouldn't happen at all - I mean the audio should be suppressed during notification sounds but not during playback from another app, right?

Last edited by klement (2015-01-28 16:31:51)

Arch Linux

#1 2015-01-27 16:21:13

Sound crackle when new sound is played while other sound already plays

#2 2015-01-27 17:11:54

Re: Sound crackle when new sound is played while other sound already plays

#3 2015-01-28 14:04:44

Re: Sound crackle when new sound is played while other sound already plays

#4 2015-01-28 15:55:44

Re: Sound crackle when new sound is played while other sound already plays

#5 2015-01-28 16:21:35

Re: Sound crackle when new sound is played while other sound already plays

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