9.10 Audio Crackles?

[Tierial]

I'm using a Dell Inspiron E1505. I'm unsure if I have a audio card in the thing or if it's an integrated controller (I'm not 100% sure how to check, if that's needed to know just tell me how to look it up and I'll post it.); However my audio seems to be crackly at times.

The audio seems to play perfectly fine most of the time. But at random points, if something like Pidgin makes a "Friend Log on sound" or something, it occasionally is just all crackly. The thing is if I'm running Skype (2.1?) and talking to people, they are clear, and the sound from the program is still crackly.

This leads me to believe it has something to do with the program or some package that's making my audio work, that isn't working right? Am I right to assume that? Thanks for any help ahead of time.

[knet]

I have the exact same problem. Sometimes when using the microphone the audio will be OK for a while, but eventually it will crackle and become impossible to understand. If I kill (HUP) 'pulseaudio' things will improve for a short time, but the problem always returns soon after.

Right now I have Skype using 'pulse' for Sound In, Sound Out, and Ringing, but I've also tried setting Sound In to use my motherboard/mic directly and many other settings.

knet

[AW36]

same here. dell dimension 8200, CS4630 santa cruz sound card
i tried getting the microphone to work, but it just doesn't like me very much.
also... a hell of a lot of crackling sound when trying to play music. movies are fine.

[sandyd]

I have the exact same problem. Sometimes when using the microphone the audio will be OK for a while, but eventually it will crackle and become impossible to understand. If I kill (HUP) 'pulseaudio' things will improve for a short time, but the problem always returns soon after.

Right now I have Skype using 'pulse' for Sound In, Sound Out, and Ringing, but I've also tried setting Sound In to use my motherboard/mic directly and many other settings.

knet

if its pulseaudio thats giving you the problems, why not simply

sudo apt-get remove pulseaudio pulseaudio-*

ubuntu will then automatically regonize that your missing pulseaudio and move back to using ALSA

[knet]

That just results in no sound at all, unfortunately.

[VertexPusher]

That just results in no sound at all, unfortunately.

Open a terminal window and enter

speaker-test

If you can't hear the test signal, check your volume settings. If you can't find a mixer in Gnome, enter

sudo apt-get install gnome-alsamixer

If you still can't hear anything, you may have two or more soundcards in your computer, and the wrong one may be selected as default. (USB headsets and webcam microphones are treated like normal soundcards.) Enter

aplay -l

to get a list of the soundcards recognized by ALSA. Each of the cards has a number and a name. The numbers may change between sessions, but the names do not. You can make ALSA select the default soundcard by name instead of always choosing card 0. Open a text editor and enter the following lines:

defaults.ctl.!card NAME
defaults.pcm.!card NAME

Replace NAME with the name of the card you want to use by default. Save the file as ".asoundrc" in your home folder. Then run speaker-test again.

Finally, make sure that Skype actually uses ALSA instead of trying to connect to PulseAudio.

[zarthon]

Periodic crackles have been noted in other versions.
Do you have hda intel audio ?

Try turning up PCM volume using gnome alsa mixer.
This is a separate volume than the pulseauido mixer.

An Explanation
Pulseaudio is a user mode sound daemon. Applications connect to pulse instead of the audio hardware directly in order to share the available audio hardware. It allows you to mix the output of different applications together, controlling each applications volume level and if you have more than one audio interface, each application's input and output hardware assignments.
For example you can use one application with a usb audio headset and play soft music on your regular audio through your speakers but crank the volume for instant messenger also using your speakers. Pulse uses ALSA and associated drivers to connect with the audio interface. ALSA volumes are separate and it seems to me set a maximum volume for pule which seems to be just a percentage of whatever volume is set in ALSA. It is similar to the relationship of the comptuer volume and the volume you might set on your audio amplifier.

[VertexPusher]

Periodic crackles have been noted in other versions.
Do you have hda intel audio ?

Don't blame Intel HDA for the crackling caused by PulseAudio. Pretty much everyone has Intel HDA these days. It is the standard that replaced AC'97. If PA can't handle it properly, it has to go.

Applications connect to pulse instead of the audio hardware directly in order to share the available audio hardware.

They can share the audio hardware without PulseAudio.

It allows you to mix the output of different applications together, controlling each applications volume level and if you have more than one audio interface, each application's input and output hardware assignments.
For example you can use one application with a usb audio headset and play soft music on your regular audio through your speakers but crank the volume for instant messenger also using your speakers.

It's nice to have one volume control per application, but what if you need two?

For example, you may want to have Skype use a USB headset for voice calls and the main soundcard for incoming message and call notifications. That means Skype needs at least two separate audio devices. However, PulseAudio treats Skype as one application and assigns one audio sink and one audio source to it. Uh-oh. Let's see what the official PulseAudio setup manual is suggesting:

Finally, open Skype. Set the "Ringing" and "Sound Out" devices to "pulse", then set the "Sound In" to the plughw device of your microphone.

The "plughw device" mentioned above is a regular ALSA PCM. How is this different from a pure ALSA setup?

Ah yes, there is a difference: The ALSA setup does not crackle, and its CPU load is lower. Bye bye, PulseAudio!

[knet]

Thanks carlee, VertexPusher & zarthon for your help so far, but I'm still having problems.

I currently have the following audio devices:

root@wopr:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC883 Analog [ALC883 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: ALC883 Digital [ALC883 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Device [Avnera Audio Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

HDA Intel on card 0. Card 1 is a USB device. I'm not using it in Linux and, whether it's plugged in or not, it has no impact on my problem.

I've removed all the pulseaudio stuff for now; I can't live with the crackling audio.

After killing the pulseaudio daemon and adjusting the mixer levels with gnome-alsamixer, I have sound. I've tested Rhythmbox and that works A-OK. However, I have no sound at all in Skype.

I've tried configuring Skype to use "Default device (default)" and every different "HDA Intel" device, but none of them work when I try to play a test sound or make a test call. There is no "alsa" option in the list of devices. Should "alsa" be in the list of devices?

I also have no mixer in the panel now. How do I add an ALSA mixer to the GNOME panel? I cannot find one in the 'Add to Panel' dialog box and gnome-alsamixer doesn't seem to have an option for minimising to the panel.

And, one last question: any suggestions on how to get my multimedia keys working again? I assume they were integrated with one of the pulseaudio tools and I'm hoping there's an ALSA equivalent solution.

Cheers and thanks for all the help guys.

David.

[Logan 1229]

if its pulseaudio thats giving you the problems, why not simply

sudo apt-get remove pulseaudio pulseaudio-*

ubuntu will then automatically regonize that your missing pulseaudio and move back to using ALSA

Well, after 4 days of pulling out my hair because of scratching, crackling sound, thanks Carlee, this seems to have worked.

Periodic crackles have been noted in other versions.
Do you have hda intel audio ?

Try turning up PCM volume using gnome alsa mixer.
This is a separate volume than the pulseauido mixer.

An Explanation
Pulseaudio is a user mode sound daemon. Applications connect to pulse instead of the audio hardware directly in order to share the available audio hardware. It allows you to mix the output of different applications together, controlling each applications volume level and if you have more than one audio interface, each application's input and output hardware assignments.
For example you can use one application with a usb audio headset and play soft music on your regular audio through your speakers but crank the volume for instant messenger also using your speakers. Pulse uses ALSA and associated drivers to connect with the audio interface. ALSA volumes are separate and it seems to me set a maximum volume for pule which seems to be just a percentage of whatever volume is set in ALSA. It is similar to the relationship of the comptuer volume and the volume you might set on your audio amplifier.

Thanks Zarthon, I now understand the 'link' between the two. I previously thought one was required to have the other.