I can add some information to this bug (or what seems to be a bunch of related audio bugs).
In my case it is related to my sound card, switching to and from the soundcard audio causes the bug to appear and disappear. Line-Out - Built-in Audio : No bug Digital Output (S/PDIF) - EMU20k2 [Sound Blaster X-Fi Titanium Series] : Occasionally garbled audio I've added more info about my hardware devices and drivers: lspci | grep Audio 00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05) 01:00.1 Audio device: NVIDIA Corporation GP102 HDMI Audio Controller (rev a1) 03:00.0 Audio device: Creative Labs EMU20k2 [Sound Blaster X-Fi Titanium Series] (rev 04) sudo lshw -C sound *-multimedia description: Audio device product: GP102 HDMI Audio Controller vendor: NVIDIA Corporation physical id: 0.1 bus info: pci@0000:01:00.1 version: a1 width: 32 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:17 memory:fb080000-fb083fff *-usb description: Audio device product: HD Webcam C615 vendor: Logitech, Inc. physical id: 2 bus info: usb@1:1.2 version: 0.11 serial: 27A1DFD0 capabilities: usb-2.00 audio-control configuration: driver=uvcvideo maxpower=500mA speed=480Mbit/s *-multimedia description: Audio device product: 6 Series/C200 Series Chipset Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 05 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:34 memory:f9300000-f9303fff *-multimedia description: Audio device product: EMU20k2 [Sound Blaster X-Fi Titanium Series] vendor: Creative Labs physical id: 0 bus info: pci@0000:03:00.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_ctxfi latency=0 resources: irq:17 memory:f9200000-f920ffff memory:f9000000-f91fffff memory:f8000000-f8ffffff -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1906741 Title: Firefox sometimes causes garbled audio Status in firefox package in Ubuntu: Confirmed Status in pulseaudio package in Ubuntu: Confirmed Bug description: Opening certain applications/websites at the same time as Firefox causes the audio to become garbled. The audio sounds distorted with an echo. Certain actions are guaranteed to cause this, but it can also happening when only running instances of Firefox. I've been able to consistently cause this by launching Zoom from a link within Firefox. This does not occur when using Chrome. The only way to fix the issue is to shut down all audio-related programs. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: firefox 83.0+build2-0ubuntu0.20.04.1 ProcVersionSignature: Ubuntu 5.4.0-56.62-generic 5.4.73 Uname: Linux 5.4.0-56-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia AddonCompatCheckDisabled: False ApportVersion: 2.20.11-0ubuntu27.12 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC2: rdevans 55475 F.... pulseaudio /dev/snd/controlC0: rdevans 55475 F.... pulseaudio /dev/snd/controlC3: rdevans 55475 F.... pulseaudio /dev/snd/controlC1: rdevans 55475 F.... pulseaudio BuildID: 20201112153044 CasperMD5CheckResult: skip Channel: Unavailable CurrentDesktop: ubuntu:GNOME Date: Thu Dec 3 16:55:36 2020 Extensions: extensions.sqlite corrupt or missing ForcedLayersAccel: False IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite) InstallationDate: Installed on 2017-10-20 (1140 days ago) InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412) IpRoute: default via 10.0.0.1 dev enp7s0 proto dhcp metric 100 10.0.0.0/24 dev enp7s0 proto kernel scope link src 10.0.0.7 metric 100 169.254.0.0/16 dev enp7s0 scope link metric 1000 Locales: extensions.sqlite corrupt or missing PrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:354 PrefSources: prefs.js Profiles: Profile0 (Default) - LastVersion=83.0/20201112153044 (In use) RunningIncompatibleAddons: False SourcePackage: firefox Themes: extensions.sqlite corrupt or missing UpgradeStatus: Upgraded to focal on 2020-11-12 (21 days ago) dmi.bios.date: 02/18/2011 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P1.40 dmi.board.name: H67M dmi.board.vendor: ASRock dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: To Be Filled By O.E.M. dmi.chassis.version: To Be Filled By O.E.M. dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.40:bd02/18/2011:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnH67M:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.: dmi.product.family: To Be Filled By O.E.M. dmi.product.name: To Be Filled By O.E.M. dmi.product.sku: To Be Filled By O.E.M. dmi.product.version: To Be Filled By O.E.M. dmi.sys.vendor: To Be Filled By O.E.M. 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