First of all, I would like to point out that most of the times audio problems are due to misconfiguration.

 

Since Ubuntu 9.10, there is a default configuration tool called “Pulseaudio” with a new interface that we can configure to match our sound preferences.

 

Right click on the speaker icon next to the hour and choose “Sound Preferences”. We find the following tabs:

• Output volume -> will be in all tabs and is the main volume. We must disable “silence” as it comes enabled by default.
• Sound Effects -> To set up alerts.
• Hardware -> We can choose the profile of your sound card and make it work one way or another depending on the capabilities of our sound card. Depending on the option we choose, we will be will enabling or disabling the correspondign “alsamixer” controls. Example: HDA-Intel has many profiles up to  5 +1 Surround, but I have two front speakers and the default “Analog Stereo Duplex” works perfectly.
• Input -> We set “connector” to the device that allows us to input sound into the machine, such as microphones, cd player … to record sound from a phone conversation for example. We can also set  volume and input level to test whether the device is working properly. We must disable “silence” as it comes enabled by default.
• Output -> We set “connector” to choose among sound output devices like normal speakers, headphones, or others.
• Applications -> shows the applications that are currently playing or recording sound.

 

 

If we do not do well with PulseAudio we can remove it and stick with ALSA which is the configuration tool bundled with Ubuntu 9.04 and earlier

 

Most people have no problems with pulseaudio, but several readers mentioned they have issues they never had before with Alsa. Many of these problems are related to the topic of microphones and audio capture (eg Skype).

 

There are plenty of guides that show how to completely remove pulseaudio from the computer and reinstall Alsa as we had in previous versions of Ubuntu.

SET THE SOUND CONTROLS WITH ALSAMIXER

 

We can enable or disable the sound controls of our card through the terminal with the following command:

alsamixer

 

 

We see there are several controls:

Card -> Model name of your sound card.

Chip -> The processor of our sound card.

View -> We navigate using the “tab” key:

 

• Playback: Controls for playback and sound output.

• Capture: Controls to set capture or recording.

• All: All the controls.

 

Below we find all the controls that should be set using the keyboard:

 

• Right and Left arrow in keyboard -> we move through the different controls from left to right and vice versa

• “m” key -> activate or deactivate control. MM means deactivated, OO means activated.

• Arrow up and down in keyboard -> raise and lower the volume.

• “Escape” Key -> Exit alsamixer and save the configuration.

 

Note: If we install gnome-alsamixer, we will have a graphical interface to modify sound options rather than the console-mode alsamixer.

 

 
 

TIPS

 

Some cards have many controls (Surround, Center, LFE, Side, CD ..) depending on whether you have 5 +1 sound, 7 +1 sound  and more. Also, control names may vary according to the sound cards.

 

But we will focus on the typical sound of a home computer, which most common controls are:

Master: The Volume that must be activated and set to the highest value.

PCM: It is also volume and must be set to the highest value.

Front: Speakers that are usually plugged into the computer and must be activated and set to the highest value.

Line Input: For playback devices, must be turned on and volume down (when not in use).

Microphone: Mostly used in phone conversations. Must be enabled and the volume down (when not in use).

Speaker: This control must be always on.

Capture: This is for sound recording, shown in the recording tab and must be activated and set to the highest level.

 

 

We should also verify that the following libraries are installed so that the audio jacks (to which connect microphones and other) remain operative:

alsaplayer-jack

libjack0

libavc1394-0

libiec61883-0

libfreebob0

 

To do this:

1. We go to System – Administration – Synaptic Package Manager.
2. Make sure that “All” to the left of the window is selected.
3. Press “Reload” to update the repositories.
4. In “Quick Search” enter the name of the packages one by one.
5. If they are not installed (white square), we double click to select them.
6. Once all the packages are selected to install, we click on the “Apply” button (with an A on it) and voila, we have all installed.

FOR UBUNTU 9.04 AND PREVIOUS VERSIONS

 

To configure Alsa, we click on the audio icon (speaker) at the top panel next to the date.

Press “Volume Control” and we will get the mixer window with several tabs.

Scroll down (if necessary) to “Preferences” and activate, if they were not on, all the controls you have for your sound card.

To make sure all the sound settings are working as expected we go to System – Preferences – Sound and click on “test” for all controls.