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Getting the Sound Working

The following steps provides information on how to get audio working on an Access Grid

Getting the sound working for your Access Grid will probably be the most difficult part of this whole process. The setup will vary, as many computer workstations generally will have different sound cards.

Audio Setup

With the release of Fedora 8, "PulseAudio is now installed and enabled by default. PulseAudio is an advanced sound server compatible with nearly all existing Linux sound systems. PulseAudio allows for hot-switching audio outputs, individual volume controls for each audio stream, networked audio, and more." as quoted from Release Highlights.

For more information about PulseAudio, it is suggested to visit the PulseAudio website.

Removal of alsa-pluggins-pulseaudio

Though not enough testing has been conducted, is has been found that the removal of the alsa-pluggins-pulseaudio works well (no guarantees that it works well without being removed) [Note that for Fedora 8, it was essential to remove this package]

By executing the command within a terminal session (as super user)

yum remove alsa-plugins-pulseaudio

will remove this package!

For other sound difficulties, it is suggested to visit http://www.pulseaudio.org/wiki/PerfectSetup.

Note: If you do some future updates, you may have to remove "alsa-plugins-pulseaudio" again, as it may get re-installed, especially if updating KDE

ALSA vs OSS Audio Device

In the past, it has always been recommended to use the OSS audio device over the ALSA device for quality reasons. A number of fixed have occurs recently within the kernel and now it is recommended to simply use the ASLA driver!

Sound Preferences

To ensure that the correct audio device is selected for both input and output channels, this can be configured within Sound preferences (Gnome menu option “System -> Preferences -> Hardware -> Sound”).

As you can see from the above image, you can select the device for capture and playback. It is recommended to select the appropriate ALSA device.

Rat Configurations

  1. Before you start to setup the sound, there is an option that needs configuring. In RAT, click on the “Options” button. This will bring up a window similar to the one below.

    fc5install-sound-setup1

  2. Click on the button “personal” and select “audio”. This will bring up another window.

    fc5install-sound-setup2

  3. Silence Suppression may be on “Automatic” by default. It is recommended that you configure this option to be “Off”. It is also recommended that the option echo Suppression is turned off as well. Once these options have been selected, click on the "Apply" Button. This will bring you back to the RAT window.

  4. To set up the sound you will need to watch the talk and listen meter levels in RAT. You will probably want to see the talk and listen meters move up until about 2-3 bars from the end when someone is talking in their normal voice, as seen below in the second.

  5. It is best to get the sound working collaboratively with other people. If the talk levels in RAT are not moving when you talk, you will need to change the input levels. When other people are talking your RAT "Listen" meter should be moving. If the meter in RAT does not move, you will need to adjust the output levels. These setting can be adjusted using "Volume Control" and/or alsamixer.

    • Another possible setting to check and test, is in the options menu within RAT: Category->Audio, check that a Audio Device is present.

Volume Control Configuration

This section of the guide describes how to configure the audio through using "Volume Control". (Note that different settings might be displayed if using a different sound card)

To open the “Volume Control” application, simply right click on the speaker icon (top right) on the gnome menu and select “Open Volume Control”.

 

Once volume control has been opened, you are able to adjust the Playback (output) and Recording (input) settings. It is also highly recommended to enable all of the Volume Control Preferences to allow the adjusting of all the required settings.

 

One of the possible “gotchas” is having the wrong input device selected. By enabling the “Input Source” option within preferences, you can configure the correct device.


Additional Settings

  1. If you are experiencing loop-back audio, or you find changing the "talk" gain has no real effect, you may have to change the “force_ac97” setting within the AudioService. This can be achieve by running the VenueClient, then selecting “Preferences” -> “Manage My Node” options within the menu.

    Then by selecting the audio service and right click and select the "Configure" option, this will display the Audio Config Dialog.

  2. Then change the setting to “true” for the force_ac97 option. Click on the “OK” button. You will then need to store the node configuration on the “Access Grid Node Management” for the changes to be saved. Remmeber to ensure this is kept standard by saving the configuration.

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