when shutting down, speakers make loud crackling noise 12.04

[garok89]

just before shutdown is complete, the speakers make a loud crackling noise
this only happens when the volume is up, when muted there is no issue

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: alsa-base 1.0.25+dfsg-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-25.40-generic 3.2.18
Uname: Linux 3.2.0-25-generic x86_64
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: ross 2011 F.... pulseaudio
 /dev/snd/controlC0: ross 2011 F.... pulseaudio
 /dev/snd/pcmC0D0p: ross 2011 F...m pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xdb100000 irq 47'
   Mixer name : 'IDT 92HD75B3X5'
   Components : 'HDA:111d7603,103c3659,00100202'
   Controls : 22
   Simple ctrls : 12
Card1.Amixer.info:
 Card hw:1 'NVidia'/'HDA NVidia at 0xd3000000 irq 16'
   Mixer name : 'Nvidia GPU 0a HDMI/DP'
   Components : 'HDA:10de000a,10de0101,00100100'
   Controls : 24
   Simple ctrls : 4
Date: Mon Jun 4 09:57:29 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Intel successful
Symptom_Card: Built-in Audio - HDA Intel
Symptom_Jack: Speaker, Internal
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: None of the above
Title: [HP Pavilion dv6 Notebook PC, IDT 92HD75B3X5, Speaker, Internal] Playback problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/17/2010
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.1C
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 3659
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 32.25
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.1C:bd05/17/2010:svnHewlett-Packard:pnHPPaviliondv6NotebookPC:pvr049D210000241210000020000:rvnHewlett-Packard:rn3659:rvr32.25:cvnHewlett-Packard:ct10:cvrN/A:
dmi.product.name: HP Pavilion dv6 Notebook PC
dmi.product.version: 049D210000241210000020000
dmi.sys.vendor: Hewlett-Packard

[Launchpad Janitor (janitor)]

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

[cro (cro)]

In addition to this, I also have the "no sound from speakers, but headphones work fine" bug (similar to but not exactly #946232)