PCM 100% is much higher than 0 dB for codec ssid 0x1631c20e

"Too high" is pretty subjective. There isn't anything misreported by your driver for dB information.

Oki, any clue how i could demonstrate the problem with logs or other ?
May be a video with sound of the startup sequence of the livecd would be efficient but i don't have actually the necessary recorder, i'll try to find one next week.
The only thing i could do actually is to use recordmydesktop and play with volume .. i give a try and post result.

I've done a record test with gtk-recordmydesktop and the result is available on google documents ogv format 4087 ko =>
http://docs.google.com/leaf?id=0ByHAVqS5yGISZjAxYWJlZTMtNjhkMy00MmNhLWIyNTMtNThkM2IzZmI1MGQw&hl

Tell me if you need more infos.

Here a record with a cam of the startup sequence of the lucid live beta 1, and some demonstration playing with volume, the problem is clear, the scale volume isn't good.
File: avi format on google documents 27 Mo =>
https://docs.google.com/leaf?id=0ByHAVqS5yGISNTUzMjI2NjEtZWFhNC00NGJhLTk0ZjYtZWU4NjM3MmFiOGNh

I just ask for some more infos or solutions about this problem, mays be some file to modify to change the scale in pulseaudio to avoid an error of manipulation on putting the sound to high and damaging my laptop.

I tried on the lucid to install alsamixer gui to modify the PCM but pulseaudio keep control of the "global" volume.

I can't view those or listen to them. Furthermore, to properly debug, you need to set all playback volumes to maximum (100%, whatever that means) and reattach output from 'amixer'.

I used alsamixer in console to put everything at maximum volume and done a amixer > amixer.txt see attachment.

PS : If you need my videos in specific format just tell i use winff and ffmpeg libs for that.

I have the same problem with what looks like a very similar chip, I would guess it's probably related:

Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)
Conexant CX20551 (Waikiki)

Basically I get distortion on all volumes because PCM is always set to around 100% by ALSA.  I had this problem in Karmic as well.

I fixed it with a config tweak that I read on a Wiki somewhere, I can't find it at the moment otherwise I would share it here.

Still no solution, i re-install lucid on a new ssd disk, and try carefully to not put sound to high by mistake (around 15%).
If somebody find a link to a tweak to fix it i take ;)

Chris, you have a different codec. Please file a separate bug report against alsa-driver.

The fix for this bug has been included upstream in kernel 2.6.34-rc7, and also cc'd to the stable kernel branch (meaning 2.6.33 and possibly 2.6.32). From the changelog:

commit 8f0f5ff6777104084b4b2e1ae079541c2a6ed6d9
Author: Daniel T Chen
Date: Wed Apr 28 18:00:11 2010 -0400

    ALSA: hda: Fix 0 dB for Packard Bell models using Conexant CX20549 (Venice)

    BugLink: https://launchpad.net/bugs/541802

    The OR's hardware distorts at PCM 100% because it does not correspond to
    0 dB. Fix this in patch_cxt5045() for all Packard Bell models.

    Reported-by: Valombre
    Cc: <email address hidden>
    Signed-off-by: Daniel T Chen
    Signed-off-by: Takashi Iwai

Good news - the fix is being reviewed for kernel 2.6.32.13-stable.

Nice the kernel that i use on lucid is 2.6.32-22-generic i guess the numbers are quite different in Ubuntu, i'll wit for the next kernel update.
Thanks for the works done ;)

Accepted linux into lucid-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

This bug was fixed in the package linux - 2.6.32-23.37

---------------
linux (2.6.32-23.37) lucid-proposed; urgency=low

  [ Alex Deucher ]

  * SAUCE: drm/radeon/kms/atom: fix dual-link DVI on DCE3.2/4.0
    - LP: #564559

  [ Andy Whitcroft ]

  * [Config] ports -- build in dm-mod to enable LVM boot
    - LP: #560717
  * tools -- fix perf version extraction for multi-part flavours
    - LP: #555130
  * SAUCE: ACPI: EC: Allow multibyte access to EC (v3)
    - LP: #526354
  * [Config] enforce -- ensure dm_mod is built-in for LVM
    - LP: #560717
  * update to ubuntu-debian:7e708d33054c373faf41da23b73e8b48c342d958
    - LP: #570500, #576274

  [ Chase Douglas ]

  * Revert "(pre-stable): input: ALPS - Add signature for HP Pavilion dm3
    laptops"
    - LP: #550625
  * Enable ftrace function profiler
    - LP: #570389
  * enforce CONFIG_TMPFS_POSIX_ACL=y
    - LP: #575940

  [ Leann Ogasawara ]

  * Revert "staging/comdi -- disable"
    - LP: #563436
  * [Config] Enable multicast routing for sparc
    - LP: #416266
  * [Config] Add ahci.ko to virtual sub-flavour
    - LP: #570542

  [ Stefan Bader ]

  * Revert "SAUCE: drm/i915: Disable FBC on 915GM and 945GM"
    - LP: #588832

  [ Tim Gardner ]

  * ubuntu: rtl8192se -- update to version 0015.0127.2010
    - LP: #567016
  * [Config] Add atl1c to nic-modules udeb
    - LP: #557130

  [ Upstream Kernel Changes ]

  * Revert "(pre-stable) iwlwifi: fix nfreed--"
    - LP: #575853
  * Revert "backlight: mbp_nvidia_bl - add five more MacBook variants"
    - LP: #575853
  * Revert "(pre-stable) pata_via: Add VIA VX900 support"
    - LP: #575853
  * Revert "(pre-stable) x86-32, resume: do a global tlb flush in S4
    resume"
    - LP: #575853
  * Revert "x86: disable IOMMUs on kernel crash"
    - LP: #575853
  * Revert "sunrpc: fix peername failed on closed listener"
    - LP: #575853
  * Revert "sunrpc: move the close processing after do recvfrom method"
    - LP: #575853
  * Revert "(pre-stable) drm/edid: allow certain bogus edids to hit a fixup
    path rather than fail"
    - LP: #575853
  * Revert "drm/radeon/kms: don't print error on -ERESTARTSYS."
    - LP: #575853
  * Revert "ath9k: fix lockdep warning when unloading module" on stable
    kernels
    - LP: #588832
  * Staging: comedi: removed "depricated" from COMEDI_CB_BLOCK
    - LP: #483343
  * fat: fix buffer overflow in vfat_create_shortname()
    - LP: #575853
  * xfs: simplify inode teardown
    - LP: #575853
  * xfs: fix mmap_sem/iolock inversion in xfs_free_eofblocks
    - LP: #575853
  * xfs: I/O completion handlers must use NOFS allocations
    - LP: #575853
  * xfs: Wrapped journal record corruption on read at recovery
    - LP: #575853
  * xfs: Fix error return for fallocate() on XFS
    - LP: #575853
  * xfs: check for not fully initialized inodes in xfs_ireclaim
    - LP: #575853
  * xfs: fix timestamp handling in xfs_setattr
    - LP: #575853
  * xfs: Don't flush stale inodes
    - LP: #575853
  * xfs: Ensure we force all busy extents in range to disk
    - LP: #575853
  * xfs: reclaim inodes under a write lock
    - LP: #575853
  * xfs: Avoid inodes in reclaim when flushing from inode cache
    - LP: #575853
  * xfs: recla...

Well, the patch is working like a charm !
The sound volume is now correctly managed good work for everyone, thanks !