broken audio/muffled, no system audio

[Dominic Anderson]

Ubuntu 18.04.1 LTS
pulseaudio:
  Installed: 1:11.1-1ubuntu7.1
  Candidate: 1:11.1-1ubuntu7.1
  Version table:
 *** 1:11.1-1ubuntu7.1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:11.1-1ubuntu7 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

expected sound to return to normal/crisp throughout system and media applications.

sound became muffled/distorted throughout all media applications, while other system sounds failed altogether. volume up/down failed. Chime on reboot also distorted. system and application sounds appear normal when used via bluetooth.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: pulseaudio 1:11.1-1ubuntu7.1
ProcVersionSignature: Ubuntu 4.15.0-30.32-generic 4.15.18
Uname: Linux 4.15.0-30-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: novgorod 1787 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Thu Aug 9 01:40:50 2018
InstallationDate: Installed on 2018-08-01 (7 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: pulseaudio
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/02/18
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MB61.88Z.00CC.B00.1802021826
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-F22C8AC8
dmi.board.vendor: Apple Inc.
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F22C8AC8
dmi.modalias: dmi:bvnAppleInc.:bvrMB61.88Z.00CC.B00.1802021826:bd02/02/18:svnAppleInc.:pnMacBook6,1:pvr1.0:rvnAppleInc.:rnMac-F22C8AC8:rvr:cvnAppleInc.:ct10:cvrMac-F22C8AC8:
dmi.product.family: MacBook
dmi.product.name: MacBook6,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

[Daniel van Vugt (vanvugt)]

Thanks for the bug report.

Firstly, please have a look in Settings > Sound and tell us the value of "Over-Amplification". It should be OFF.

[Daniel van Vugt (vanvugt)]

Also, while in Settings > Sound, click on "Test Speakers". Does the speaker test play cleanly?

[Daniel van Vugt (vanvugt)]

Next, if sound used to work on this machine in an older version of Ubuntu then please tell us what that version was.

[Dominic Anderson (novgorod)]

Over-Amplification is set to "OFF"

Test Speakers returned no sound from either left or right speaker.

Previous version of Ubuntu "16.04 LTS"

[Daniel van Vugt (vanvugt)]

Thanks. If the sound worked fine in Ubuntu 16.04 then that's useful information. 16.04 used kernel 4.4 and you are presently using kernel 4.15

Next, please try installing an older kernel version and see if that fixes the problem.

1. Download these:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.146/linux-headers-4.4.146-0404146_4.4.146-0404146.201808061143_all.deb
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.146/linux-headers-4.4.146-0404146-generic_4.4.146-0404146.201808061143_amd64.deb
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.146/linux-image-4.4.146-0404146-generic_4.4.146-0404146.201808061143_amd64.deb

2. In a terminal run:
  cd ~/Downloads
  sudo dpkg -i linux*4.4.146*deb

3. Reboot and hold down Shift at start-up to choose the different kernel version.

4. Now check the new kernel is active by running:
  uname -a
and send us the output.

[Dominic Anderson (novgorod)]

uname -a
Linux novgorod-LinuxBook 4.4.146-0404146-generic #201808061143 SMP Mon Aug 6 15:51:56 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

[Dominic Anderson (novgorod)]

"16.04 used kernel 4.4 and you are presently using kernel 4.15"

Have been running 18.04 for a week. Until earlier today issue was not present, each day until now however, had been just fine. Is "4.15" the same kernel used at install of "18.04"?

[Chorca (chorca)]

Having what I believe is the same issue. Internal Intel HDA audio is distorted at normal maximum volume on Xubuntu, at 100% and not above. Seems to be distorted at lower volume levels as well. System sounds are distorted as well as sounds from media applications. This is recent to me as it seems to have been working fine less than a month ago.

[Daniel van Vugt (vanvugt)]

Dominic: Can you please rephrase that? Was the bug gone when using kernel 4.4? And yes Ubuntu 18.04 ships with kernel 4.15, which is why we need you to test downgrading the kernel to an older version.

Chorca: Please log a new bug of your own.

[Dominic Anderson (novgorod)]

The bug was not gone when using kernel 4.4

there was also an additional kernel between 4.4 and 4.15 that was available. I tried that as well. same result.no fix.

Since then I backed up my system and did a completely fresh install of 18.04LTS and the issue is still not fixed.

[Chorca (chorca)]

My issue seems to be localized to only the right speaker on a Thinkpad x270, and the issue happens in Windows as well, so it may be due to a blown speaker on my laptop.