Arch Linux

degmic71

Member

Registered: 2009-02-03

Posts: 122

[SOLVED] Bad Sound Quality, Audacity, playback , via browser

Playback on the following page is fine:

https://soundcloud.com/playmerecords/ja … vy-jayne-2

Original File, downloaded via official channe :
https://www.dropbox.com/sh/u9683vhoqqn2 … mix%29.mp3

My sample from Audacity
https://www.dropbox.com/sh/u9683vhoqqn2 … 20-%20.mp3

Images of configs and programs:
https://dl.dropboxusercontent.com/u/3044885/issue1.png
https://dl.dropboxusercontent.com/u/3044885/issue2.png
https://dl.dropboxusercontent.com/u/3044885/issue3.png
https://dl.dropboxusercontent.com/u/3044885/issue4.png
https://dl.dropboxusercontent.com/u/3044885/issue5.png

System Info:

Linux ArchBoxMTD 3.10.7-1-ARCH
AlsaMixeer v1.0.27.2
Pulseaudio 4.0
Audacity 2.0.3 (official package from Arch)

But, when I record with Audacity, playback (before exporting), is shoddy.  I noticed my dB levels lower than normal when monitoring my audio/recording in Audacity.  Before I remember I had to even LOWER the default dB level of recording in pavucontrol/sound center.  I've done this many times on Arch, and I have had no new hardware.  I have tried changing the output/input device on the main screen in Audacity several times to no effect.  I never had to before.  Now, on Arch I have always had to set the inital dB recording level via sound prefs, not via Audacity as the "Input Volume" slider on Audacity was always grayed out, but never an issue before.

If you need additional information, please let me know. 

Thank you

_professor

Last edited by degmic71 (2013-08-22 15:58:09)

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

isnt that what dubstep is supposed to sound like these days?
(sorry bad joke)

on a serious tip, that simply sounds like you've got too much gain somewhere and the audio gets clipped.
did you check alsamixer that everything is at 0db or lower there (especially capture channels)? afaik pavucontrol doesn't change alsa mixer settings.

degmic71

Member

Registered: 2009-02-03

Posts: 122

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

This is my alsamixer set:

http://i.imgur.com/pbLTZJp.png

Thank you for any help.  I appreciate it.  The problem is (see previous 5 screenshots) is at 0dB level on recording, its too low in Audacity.  And even then the quality sucks.  Not sure what I did this time vs. last time with Arch.

UPDATE:  Got it! you were right!  I didn't see the front channel had a gain of 2 dB.  YES..... thanks for the suggestion man.

On a side note: Why is it that you can't modify the mic level / record level in audacity?  I always have to use the sound settings.

**UPDATE2***

Now check this out....The dB level of recording is too high when recording in Audacity, short of hitting the menu, if I lower the left/right record volume in pavucontrol, it lowers it but adacity's wave
lengths look really funny:
http://i.imgur.com/TkIWse2.png

As soon as I exit pavucontrol, the wavelengths look fine again, and the "lowered record input" stays.... very odd.  But it works!
http://i.imgur.com/kKhgbT3.png

Last edited by degmic71 (2013-08-21 21:48:33)

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

can you tell a bit more of how you're doing the recording (via line-in port or from software or somewhere somehow?)

in alsamixer, if you press f4, you'll see capture (input) mixer levels which are usually more relevant when recording.
at least the screenshot you provided only shows output levels so I'm assuming you only checked those.

I'm suspecting you have too much gain somewhere in alsa capture ports which distorts the sound just like that.
if you lower the volume of audio signal after that from pulseaudio or audacity, it will stay distorted, but with lower volume, which would usually make the waveform look just like on the second screenshot.

degmic71

Member

Registered: 2009-02-03

Posts: 122

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

Here is my capture interface in alsamixer:
http://i.imgur.com/GfZVNy

When I modified that a little up/down it actually messed up the levels so I had to go back into pavucontrol to raise the recording level.  See Update 1 , the first update in my previous post.  I believe the issue was originally the cause of a +2 dB gain on the front speakers.  Eitehr way I still find it odd pavuconrol provides what I needed... stinks, but that is pulse/alsa haha.   Do you suggest a different sound system/control ?  What about Jack2?

Zazzman

Member

Registered: 2011-12-26

Posts: 34

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

Sounds like the difference between the kernel having the *real time* modules active, and not while pulseaudio is trying to use them.

Pulseaudio sometimes demands that feature for skype and audacity, but *never* of webbrowsers.

try this: edit '/etc/pulse/daemon.conf' or wherever it is on this distro, and look for an option about "realtime" and set that equal to "0" if it exists as a "1".  Turn that sucker off.

Alternatively, you could recompile your kernel to include realtime priority - in which case, you'd want to put this option back to normal.  If you experience terrible latency with your sound apps (that isn't from the internets) this is probably the best bet.

Last edited by Zazzman (2013-08-22 01:22:44)

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

well if it works for you now then there's no reason to fix it I guess..

imho, if bare alsa works for you (like it has always worked for me) pulseaudio is just an unnecessary layer.
unless of course it has some feature you really need that you can't get with alsa.

if youre having some issue with alsa that can't be resolved with plugins (or you just don't want to mess with asound.conf since it can be quite painful at first), go for pulseaudio if it works.

jack is generally only useful if youre making music or other pro audio stuff. No point of using it as general purpose sound server over pulseaudio unless you're actually sure you need it for something. It's usually quite a hassle to set up as well.

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

Alternatively, you could recompile your kernel to include realtime priority - in which case, you'd want to put this option back to normal.  If you experience terrible latency with your sound apps (that isn't from the internets) this is probably the best bet.

you don't need to recompile kernel to get realtime priority. see https://wiki.archlinux.org/index.php/Pu … scheduling

realtime kernel on the other hand is just completely different thing and totally unrelated.

degmic71

Member

Registered: 2009-02-03

Posts: 122

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

I'll just mark this solved, since it was more of a quirk, than a huge issue.  Now I now what happened, albeit strange.  I will try bare alsa without pulse.  But before I mark this solved, what is the difference/implication of using just alsa vs both/just pulse?

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

first of all, if your pulseaudio setup is working for you there's no reason to break it really..

historically, the reason for using sound servers like pulseaudio over alsa, is that some sound cards don't support hardware mixing with alsa, which means you coudn't play audio from eg. audacious and youtube at the same time. Nowadays alsa has software mixing support (via dmix plugin if I'm not mistaken) so Its not usually an issue any more.

I have very limited experience with pulseaudio, and can't be sure of the differences. Generally I believe alsa can do most of the stuff pulseaudio can, but if you've ever looked at configuring alsa, you might know it could be a real pita especially in more advanced setups. From my limited experience with pulseaudio, I think it could be easier to set up on some cases and often just works out of the box. I could also have some audio over network capabilities that alsa might lack, but that again is just my assumption.

also I'm pretty sure pulseaudio is required for some desktop environments like gnome.

just use whatever method works for you

degmic71

Member

Registered: 2009-02-03

Posts: 122

Re: [SOLVED] Bad Sound Quality, Audacity, playback , via browser

first of all, if your pulseaudio setup is working for you there's no reason to break it really..

historically, the reason for using sound servers like pulseaudio over alsa, is that some sound cards don't support hardware mixing with alsa, which means you coudn't play audio from eg. audacious and youtube at the same time. Nowadays alsa has software mixing support (via dmix plugin if I'm not mistaken) so Its not usually an issue any more.

I have very limited experience with pulseaudio, and can't be sure of the differences. Generally I believe alsa can do most of the stuff pulseaudio can, but if you've ever looked at configuring alsa, you might know it could be a real pita especially in more advanced setups. From my limited experience with pulseaudio, I think it could be easier to set up on some cases and often just works out of the box. I could also have some audio over network capabilities that alsa might lack, but that again is just my assumption.

also I'm pretty sure pulseaudio is required for some desktop environments like gnome.

just use whatever method works for you

I remember having that EXACT issue back in ~04-06.  That was the most annoying thing, and the reason why I started to use pulse back then.  Oh I know the pitfalls of alsa, which is why I understand pulse co-existing on Arch's cinnamon package setup.  Cool, well thanks for the advice!