HDMI audio is severely distorted.

[Luke]

I have recently installed Ubuntu onto a newly built computer with an ASRock H87 Performance Motherboard. I am using a TV monitor for a screen, connected with HDMI. The visuals work fine but the audio is severely distorted and echoes.

When testing the sound in the hardware settings, it sounds like "FRONTFRONTFRONTFRONT" with static or overdrive getting more and more prominent as the sound goes on. I have changed the Alsamixer levels but found no change. The built-in sound card also shows up when i look for it as per the Sound Troubleshooting page.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: alsa-base 1.0.25+dfsg-0ubuntu4
ProcVersionSignature: Ubuntu 3.13.0-30.55-generic 3.13.11.2
Uname: Linux 3.13.0-30-generic x86_64
NonfreeKernelModules: snd_hda_codec_generic snd_hda_controller fglrx
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: luke 2371 F.... pulseaudio
 /dev/snd/controlC1: luke 2371 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Jul 10 17:52:52 2014
InstallationDate: Installed on 2014-07-09 (1 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Generic failed
Symptom_Card: HD-Audio Generic - HD-Audio Generic
Symptom_Jack: Digital Out, HDMI
Symptom_Type: Digital clip or distortion, or "overdriven" sound
Title: [To Be Filled By O.E.M., ATI R6xx HDMI, Digital Out, HDMI] Sound is distorted
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/06/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P2.10
dmi.board.name: H87 Performance
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.:bvrP2.10:bd05/06/2014:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnH87Performance:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: 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.

[GeeMac (htpc2013)]

Hello,

Yes this is probably too little-too late, but maybe someone else can benefit from it.

I'm not an expert at this and neither a Dev or Programmer, but this is what I did to correct my situation here with the audio via HDMI to my TV.
Below I used leafpad for my editor, pick your own poison...
----------------------------
First was default.pa

sudo leafpad /etc/pulse/default.pa

If you are using line numbers it is roughly line 53:

Original line...
load-module module-udev-detect
Added to the end of this line was tsched=0
Now...
load-module module-udev-detect tsched=0

So after the first fail which has worked for others, I changed the sample rate which apparently was too low for my Visio TV.
Next was daemon.conf:

sudo leafpad /etc/pulse/daemon.conf

Roughly lines 81 and 82:

Original lines...
default-sample-rate = 41000
alternate-sample-rate = 48000

Changed to...
default-sample-rate = 48000
alternate-sample-rate = 96000

The sample rate change was the charm that worked for my hardware situation.
No more distortion and chopping/clipping sounds during standard vocal or incidental music while watching recordings or live streams.

Cheers
G

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Sancho (sancho-sancho)]

Thanks, fixed my Cosmic, too :)