[gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Ignas Anikevicius]

Dear all,

It's been quite a while since I noticed this annoying behaviour, but I
could not find any information what might cause this. So the problem is
that at lower volumes my HD-Audio with Conexant becomes very noisy and
this is regardless of the sound system or speakers/headphones I use.

The noise can be described, as high pitched, sandy texture noise
heard during more expressive parts of the music or speech.

I experience this on two Thinkpads (x200s and x200) and it very evident
when I connected external speakers, they produced a lot of this noise,
or maybe I just could hear it better, because of the frequency response
of the speakers.

Does anybody have some similar issues?

My current audio setup:

    * PulseAudio (but the problem is experienced with ALSA as well)
    * MPD for music playing
    * Conexant and other related modules compiled in, power-saving
      features enabled.

What I have tried to eliminate the noise:

    * Various levels of Master,PCM,Headphone channels via Alsamixer
    * Increase the sample rate in MPD settings.

The noise can be clearly head when I Have the following setting on my
Alsamixer:

    * Master ~50
    * PCM 100
    * Headphone 100

Does anybody has any thoughts on why am I experiencing this?

Thanks a lot,
Ignas A.

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Alecks Gates]

On Tue, May 15, 2012 at 11:28 AM, Ignas Anikevicius
<anikevicius@gmail.com> wrote:
> Dear all,
>
> It's been quite a while since I noticed this annoying behaviour, but I
> could not find any information what might cause this. So the problem is
> that at lower volumes my HD-Audio with Conexant becomes very noisy and
> this is regardless of the sound system or speakers/headphones I use.
>
> The noise can be described, as high pitched, sandy texture noise
> heard during more expressive parts of the music or speech.
>
> I experience this on two Thinkpads (x200s and x200) and it very evident
> when I connected external speakers, they produced a lot of this noise,
> or maybe I just could hear it better, because of the frequency response
> of the speakers.
>
> Does anybody have some similar issues?
>
> My current audio setup:
>
>    * PulseAudio (but the problem is experienced with ALSA as well)
>    * MPD for music playing
>    * Conexant and other related modules compiled in, power-saving
>      features enabled.
>
> What I have tried to eliminate the noise:
>
>    * Various levels of Master,PCM,Headphone channels via Alsamixer
>    * Increase the sample rate in MPD settings.
>
> The noise can be clearly head when I Have the following setting on my
> Alsamixer:
>
>    * Master ~50
>    * PCM 100
>    * Headphone 100
>
> Does anybody has any thoughts on why am I experiencing this?
>
> Thanks a lot,
> Ignas A.
>

I would check the inputs in alsamixer and play around with them.  I
had a problem similar to this for many months and it was due to some
funny input volume I didn't need, so I muted it.

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Ignas Anikevicius]

On 15/05/12 17:31, Alecks Gates wrote:
> I would check the inputs in alsamixer and play around with them.  I
> had a problem similar to this for many months and it was due to some
> funny input volume I didn't need, so I muted it.

Thanks for replying, I have muted everything, except Headphones, Master,
Speaker and PCM outputs, which *are* necessary to get any sound out of
my machine either with headphones or speakers. Muting speakers when only
headphones were used did not help.

Cheers,
I.

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Michael Mol]

On Tue, May 15, 2012 at 12:28 PM, Ignas Anikevicius
<anikevicius@gmail.com> wrote:
> Dear all,
>
> It's been quite a while since I noticed this annoying behaviour, but I
> could not find any information what might cause this. So the problem is
> that at lower volumes my HD-Audio with Conexant becomes very noisy and
> this is regardless of the sound system or speakers/headphones I use.
>
> The noise can be described, as high pitched, sandy texture noise
> heard during more expressive parts of the music or speech.
>
> I experience this on two Thinkpads (x200s and x200) and it very evident
> when I connected external speakers, they produced a lot of this noise,
> or maybe I just could hear it better, because of the frequency response
> of the speakers.
>
> Does anybody have some similar issues?
>
> My current audio setup:
>
>    * PulseAudio (but the problem is experienced with ALSA as well)
>    * MPD for music playing
>    * Conexant and other related modules compiled in, power-saving
>      features enabled.
>
> What I have tried to eliminate the noise:
>
>    * Various levels of Master,PCM,Headphone channels via Alsamixer
>    * Increase the sample rate in MPD settings.
>
> The noise can be clearly head when I Have the following setting on my
> Alsamixer:
>
>    * Master ~50
>    * PCM 100
>    * Headphone 100
>
> Does anybody has any thoughts on why am I experiencing this?

I have a strong expectation that part of what you're hearing is system
electrical noise.

What happens when you set:

* Master -> 100
* Headphone -> 100
* Everything else -> 0

...but you're not playing anything? If you hear anything, then what
you're hearing isn't something you can really deal with without using
an external sound card. Any USB sound card would do fine. (A pair of
'gamer' headphones I bought at Best Buy advertised USB support...and
it turns out they were packaged with a tiny USB<->3.5mm sound
adapter.)

If you don't hear the characteristic sound you're describing, then I'd
expect you're encountering clipping. That's when the logical amplitude
of a signal is greater than the medium holding it, and that happens a
*lot* with integer PCM mixing and amplification.

Unfortunately, there's little to no standardization as to what '0' and
'100' mean between audio chipsets, so the best you can really do here
is crank all of your sliders to maximum, and decrease some of them
until you no longer hear the clipping. (And then remember which
positions on the relevant sliders that corresponds to; it usually
means you're getting no amplification, but also no attenuation.)

-- 
:wq

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Ignas Anikevicius]

On 15/05/12 17:52, Michael Mol wrote:
> I have a strong expectation that part of what you're hearing is system
> electrical noise.
> 
> What happens when you set:
> 
> * Master -> 100
> * Headphone -> 100
> * Everything else -> 0

If I do not play anything while PCM is at 0 and Master and Headphone are
at 100, then I do not hear anything. But if I start 'playing' something
while still with PCM at 0 (no sound can be heard), then I start hearing
irregular clipping sound.

Is that what you expected?

If I decrease the sound to a level where I stop hearing clipping, then I
can barely hear the music. Although the same headphones play on my
player fine.

And It's a shame, that I indeed hear clipping. Are there any ways to
increase the sound volume without increasing the mixer setting in ALSA?
Would a different sound card help? Is there any way I can solve the
problem without buying new hardware?

Thanks a lot for help,
I.

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Michael Mol]

On Tue, May 15, 2012 at 2:55 PM, Ignas Anikevicius
<anikevicius@gmail.com> wrote:
> On 15/05/12 17:52, Michael Mol wrote:
>> I have a strong expectation that part of what you're hearing is system
>> electrical noise.
>>
>> What happens when you set:
>>
>> * Master -> 100
>> * Headphone -> 100
>> * Everything else -> 0
>
> If I do not play anything while PCM is at 0 and Master and Headphone are
> at 100, then I do not hear anything. But if I start 'playing' something
> while still with PCM at 0 (no sound can be heard), then I start hearing
> irregular clipping sound.
>
> Is that what you expected?
>
> If I decrease the sound to a level where I stop hearing clipping, then I
> can barely hear the music. Although the same headphones play on my
> player fine.
>
> And It's a shame, that I indeed hear clipping. Are there any ways to
> increase the sound volume without increasing the mixer setting in ALSA?

There are going to be multiple sliders which affect your playback
volume. Without seeing a list of your sliders, I couldn't really guess
which, beyond 'Master', 'PCM' and 'Headphone'. There may be others; my
old Sound Blaster Live had a ton of internal signal processing
sliders, and anything that involves amplification presents that risk.

Each one of those will likely have a threshold where you'll risk
clipping if you go above it. I.e. if PCM and Headphone are at 50, but
Master is above $master_threshold, you may hear clipping. Likewise, if
Master and Headphone are at 50, but PCM is above $pcm_threshold, you
may hear clipping. Similarly, 'Headphone'...

There is probably a combination of settings which works best, and
sounds fine. The trouble, of course, is finding the maximum safe
threshold for each.

Me, I'm fortunate; my Intel-HDA-compatible cards all tend to say
things like "-5dB" or "+20dB" when I'm using the console Alsamixer,
and I've established that as long as they say "0dB", I get the best
signal I can get.

> Would a different sound card help?

Sure; you could use a card with more post-mixer amplification. Or a
card with little to no mixing options. Or an external amplifier.

> Is there any way I can solve the
> problem without buying new hardware?

You might try using something like PulseAudio, which may be doing
internal mixing in the floating point space before it maps back to
16-bit linear PCM. My experiences with PulseAudio have generally been
positive in terms of audio quality. The trickiest part is getting
applications to pipe their audio through it, followed by getting
direct access to the card's mixer settings if I need it. But
"pavucontrol" as a mixer control for PulseAudio works reasonably well
for the majority of circumstances.

>
> Thanks a lot for help,

np.

(Note: I CC'd this back to the main list, because somehow this one got
sent to me directly. Channeling communications through the main list
keeps the archives useful.)

-- 
:wq

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Ignas Anikevicius]

On 15/05/12 20:08, Michael Mol wrote:
> There are going to be multiple sliders which affect your playback
> volume. Without seeing a list of your sliders, I couldn't really guess
> which, beyond 'Master', 'PCM' and 'Headphone'. There may be others; my
> old Sound Blaster Live had a ton of internal signal processing
> sliders, and anything that involves amplification presents that risk.

[...] (some useful stuff snipped :))

At the moment all the other sliders are at 0. So I do not know, maybe
some other sliders are doing this...

Also, ALSA can show the levels in dBs for my card... but I get sand even
when I'am at gain of ~ (-11,-14)dB on all three sliders (Master, PCM,
Headphone).

> You might try using something like PulseAudio, which may be doing
> internal mixing in the floating point space before it maps back to
> 16-bit linear PCM. My experiences with PulseAudio have generally been
> positive in terms of audio quality. The trickiest part is getting
> applications to pipe their audio through it, followed by getting
> direct access to the card's mixer settings if I need it. But
> "pavucontrol" as a mixer control for PulseAudio works reasonably well
> for the majority of circumstances.

I am using Pulse :)... The problem with I have that it changes my PCM
and Headphone levels without asking me... Therefore, if I change the
levels manually on alsamixer and then use Pavucontrol, it just changes
the PCM and headphone or speaker levels to max, which makes the sound
crappy. Otherwise I am quite a happy Pulse user. :)

Is there a way to set the limiting thresholds? Or maybe I am using two
things at the same (ALSA and Pulse) and they are clashing and,
therefore, I can not get good quality sound?

>> Thanks a lot for help,
> 
> np.
> 
> (Note: I CC'd this back to the main list, because somehow this one got
> sent to me directly. Channeling communications through the main list
> keeps the archives useful.)

I thought, that I have replied to both, list and you.. :) Well, thanks
for that. :)

Cheers,
I.

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Michael Mol]

On Tue, May 15, 2012 at 3:29 PM, Ignas Anikevicius
<anikevicius@gmail.com> wrote:
> On 15/05/12 20:08, Michael Mol wrote:
>> There are going to be multiple sliders which affect your playback
>> volume. Without seeing a list of your sliders, I couldn't really guess
>> which, beyond 'Master', 'PCM' and 'Headphone'. There may be others; my
>> old Sound Blaster Live had a ton of internal signal processing
>> sliders, and anything that involves amplification presents that risk.
>
> [...] (some useful stuff snipped :))
>
> At the moment all the other sliders are at 0. So I do not know, maybe
> some other sliders are doing this...

Not if they're at their minimum settings. :-|

>
> Also, ALSA can show the levels in dBs for my card... but I get sand even
> when I'am at gain of ~ (-11,-14)dB on all three sliders (Master, PCM,
> Headphone).
>
>> You might try using something like PulseAudio, which may be doing
>> internal mixing in the floating point space before it maps back to
>> 16-bit linear PCM. My experiences with PulseAudio have generally been
>> positive in terms of audio quality. The trickiest part is getting
>> applications to pipe their audio through it, followed by getting
>> direct access to the card's mixer settings if I need it. But
>> "pavucontrol" as a mixer control for PulseAudio works reasonably well
>> for the majority of circumstances.
>
> I am using Pulse :)... The problem with I have that it changes my PCM
> and Headphone levels without asking me... Therefore, if I change the
> levels manually on alsamixer and then use Pavucontrol, it just changes
> the PCM and headphone or speaker levels to max, which makes the sound
> crappy. Otherwise I am quite a happy Pulse user. :)

Run alsamixer in a terminal while playing with pavucontrol; you'll see
Alsamixer update live while Pulse tweaks ALSA's mixer settings. It's
useful if you want to get a feel for what exactly Pulse is doing.

On my desktop system, I found that if I had the Pulse master volume
control set to about 70%, Pulse would have my various sliders set to
just about their maximum setting before I started getting clipping
noises.
>
> Is there a way to set the limiting thresholds?

No; the limiting thresholds I was describing are some value that just
happens to be what it is because of the way your sound card mixes
audio together.

> Or maybe I am using two
> things at the same (ALSA and Pulse) and they are clashing and,
> therefore, I can not get good quality sound?

Pulse is usually OK at managing ALSA in the background; you just have
to do all your volume tweaking through pavucontrol if you intend for
things to not change on you.

[snip]

>> (Note: I CC'd this back to the main list, because somehow this one got
>> sent to me directly. Channeling communications through the main list
>> keeps the archives useful.)
>
> I thought, that I have replied to both, list and you.. :) Well, thanks
> for that. :)

Might have been a quirk in my GMail interface, now that I look at it.
Your earlier email looks fine. Something about the list's distribution
pattern changed, so simply clicking "Reply" doesn't work; I now have
to click "Reply All".

Anyway, I'd try taking others' suggestions, too, and possibly poking
whatever PulseAudio support groups exist. They'll be interested in
your circumstance. If it's possible to use Pulse reasonably on your
hardware, they'll want to figure out how to make that less difficult
to do.

Also, Mark noted that there were sliders he hadn't tweaked before when
he was experiencing similar issues, and it's plausible Pulse isn't
poking those at all. Try watching alsamixer to see what Pulse is up
to, and see if Pulse is passing over some of those sliders.

-- 
:wq

Re: [gentoo-user] Advice Needed: Conexant HD-Audio noisy audio

[Mark Knecht]

On Tue, May 15, 2012 at 9:28 AM, Ignas Anikevicius
<anikevicius@gmail.com> wrote:
> Dear all,
>
> It's been quite a while since I noticed this annoying behaviour, but I
> could not find any information what might cause this. So the problem is
> that at lower volumes my HD-Audio with Conexant becomes very noisy and
> this is regardless of the sound system or speakers/headphones I use.
>
> The noise can be described, as high pitched, sandy texture noise
> heard during more expressive parts of the music or speech.
>
> I experience this on two Thinkpads (x200s and x200) and it very evident
> when I connected external speakers, they produced a lot of this noise,
> or maybe I just could hear it better, because of the frequency response
> of the speakers.
>
> Does anybody have some similar issues?
>
> My current audio setup:
>
>    * PulseAudio (but the problem is experienced with ALSA as well)
>    * MPD for music playing
>    * Conexant and other related modules compiled in, power-saving
>      features enabled.
>
> What I have tried to eliminate the noise:
>
>    * Various levels of Master,PCM,Headphone channels via Alsamixer
>    * Increase the sample rate in MPD settings.
>
> The noise can be clearly head when I Have the following setting on my
> Alsamixer:
>
>    * Master ~50
>    * PCM 100
>    * Headphone 100
>
> Does anybody has any thoughts on why am I experiencing this?
>
> Thanks a lot,
> Ignas A.
>

Hi Ignas,
   I've never used pulse-audio so I cannot help with that, but with
plain Alsa I had a similar (but not identical) problem recently. In my
case the distorted sound was primarily from my microphone and not, as
I remember it, from playback. Turned out it was a control I hadn't
looked at before called 'Digital' which apparently mixes audio in the
sound chip and for whatever reason was very dirty sounding on the mic
side.

   Note that my audio is not Conextent but rather something called
SupremeFX X-Fi (Creative Labs maybe?) so your results will almost
certainly vary. A little machine info is below.

Good luck,
Mark

c2stable ~ # lspci | grep Audio
00:1b.0 Audio device: Intel Corporation 82801JI (ICH10 Family) HD
Audio Controller
02:00.1 Audio device: nVidia Corporation GF100 High Definition Audio
Controller (rev a1)
04:00.1 Audio device: nVidia Corporation High Definition Audio
Controller (rev a1)
c2stable ~ #

c2stable ~ # lsmod
Module                  Size  Used by
vmnet                  32295  15
vmblock                 9667  0
vsock                  35510  2
vmci                   55922  2 vsock
vmmon                  56524  5
vboxnetadp              4720  0
vboxnetflt             13187  0
vboxdrv              1760740  3 vboxnetadp,vboxnetflt
nvidia              12297407  104
snd_hda_codec_hdmi     22531  8
snd_hda_codec_analog    80332  1
sky2                   42693  0
i2c_i801                7674  0
snd_hda_intel          21907  17
snd_hda_codec          73637  3
snd_hda_codec_hdmi,snd_hda_codec_analog,snd_hda_intel
snd_hwdep               5508  1 snd_hda_codec
snd_pcm                74632  7 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec
snd_timer              18381  5 snd_pcm
snd                    58592  33
snd_hda_codec_hdmi,snd_hda_codec_analog,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_timer
soundcore               6750  1 snd
snd_page_alloc          7340  2 snd_hda_intel,snd_pcm
agpgart                31204  1 nvidia
c2stable ~ #