Section 1.11. I Need to Manage Sound Events | Linux Annoyances for Geeks: Getting the Most Flexible System in the World Just the Way You Want It

1.11. I Need to Manage Sound Events

In this annoyance, I describe the elementary utilities available to our major distributions for configuring sound cards. I then describe the utilities that can help you manage sound events. As this chapter is focused on the desktop, I focus on sound events associated with the GNOME and KDE desktop environments. I also focus on the Advanced Linux Sound Architecture (ALSA), which was incorporated into the current Linux kernel (2.6). If you need detailed information on support for your sound card, refer to ALSA's web site at http://www.alsa-project.org.

When your distribution detects a sound card, it may include commands for the appropriate modules in a file such as /etc/modprobe.conf, /etc/modules.conf, or /etc/modprobe.d/sound.

I've broken this annoyance into distribution-specific sections, followed by the tools associated with the GNOME and KDE desktop environments. You can control the sound environment for all users with the distribution-specific tools. Your users can control their individual sound settings with the GNOME and KDE-based tools.

All three distributions include the alsaconf utility. As you can run it from the console, it's not associated with any particular desktop environment. For more information, see the description of the utility later in this annoyance.

1.11.1. Red Hat/Fedora

Immediately after the installation process, Red Hat/Fedora distributions normally test the sound card as part of the firstboot process. This process calls the system-config-soundcard utility. If it finds an ALSA-compliant sound card, it installs the card for you and allows you to check the result with a standard set of musical notes.

For more details on how you can configure ALSA-compliant sound cards, refer to the commands associated with the alsa-utils RPM. This package includes a number of utilities that can even help you configure and coordinate multiple sound cards.

1.11.2. SUSE

As with most systems, SUSE encourages hardware configuration of sound cards with YaST. Sound configuration options are available when you start YaST, under the Hardware section.

If SUSE detects a sound card, it's listed in the YaST Sound Configuration menu. Alternatively, if the card wasn't properly detected, you may be able to configure it from the available database. In the YaST Sound Configuration menu, select the Add Sound Card option. You'll be able to select from a wide variety of sound-card vendors and associated hardware models.

YaST configures your sound card and adds the result to the /etc/modprobe.d/sound configuration file. Other important SUSE sound configuration files include /etc/modprobe.conf* and /etc/sysconfig/sound.

1.11.3. Debian and alsaconf

Debian includes the generic ALSA configuration tool, /usr/sbin/alsaconf. While available for the distributions covered in this book, it's the primary tool for Debianpart of the alsa-utils package. Install it, and it can help you configure just about any ALSA-compatible sound card. While you're at the installation process, make sure to download and install the alsa-source, alsa-base, and the libasound2 packages. As the database of ALSA drivers, the alsa-source package is especially important if you have a slightly obscure sound card.

The alsaconf tool is available as part of the alsa RPM in SUSE Linux; for Red Hat/Fedora, it's been superseded by system-config-soundcard.

When you start the ALSA configuration tool, take the following steps:

Stop all currently running applications that require sound, such as Real Player.
Start the ALSA configuration tool with the /usr/sbin/alsaconf command. When you click OK, it unloads any currently running ALSA kernel modules and loads the ALSA sound-card database.
The tool should find any ALSA-compatible cards. If you're not satisfied with the results, refer to the documentation and mailing lists at http://www.alsa-project.org/.
If you have a legacy sound card, select the legacy option. The steps that follow allow you to probe, using the drivers, for several different fairly generic sound cards.

Any special sound-card settings are saved to the /etc/modprobe.d/alsa-base file.

If you want to make sure any changes to sound settings are saved and reapplied the next time you boot Debian Linux, take the following steps:

Stop the ALSA service with the following command:
```
 /etc/init.d/alsa stop 
```
Use the dpkg-reconfigure command to reset the ALSA base parameters:
```
 dpkg-reconfigure alsa-base 
```
You'll be able to select from three options: to always autosave, to autosave once at next shutdown, or to never autosave.
If you select always autosave, Debian Linux always saves your sound settings when it shuts down. The setting is saved as the alsactl_store_on_shutdown directive in the /etc/default/alsa configuration file.

Now, you can adjust the default sound settings for your system. To do so, run the alsamixer command, which opens a console-based volume tool, as shown in Figure 1-9.

Figure 1-9. AlsaMixer

You can navigate among the options with the left and right arrow keys, and change volume levels with the up and down arrow keys. As shown in the figure, you can exit the utility with the Esc key.

Once you make changes, you'll need to run the following command to store the current sound level in /var/lib/alsa/asound.state:

 alsactl store

1.11.4. GNOME Sound Preferences

GNOME sound events are managed through the Sound Preferences tool, which you can start with the gnome-sound-properties command. It's part of the capplets package in Debian, the control-center RPM on Red Hat/Fedora, and the control-center2 RPM on SUSE.

When you start this utility, you'll immediately see its value. As shown on the first tab, it determines whether the sound server is started when you log in to the GNOME Desktop Environment. It also allows you to activate Sounds For Events, as defined under the Sound Events tab. Many of these events require the gnome-audio RPM or DEB package.

The System Bell tab allows you to activate a sound for events such as errors. One standard is to activate the Sound An Audible Bell option. For hearing-impaired users, you can also activate visual feedback, which leads to a flash on the screen for sound events.

Sound-event settings are saved in gconf (GNOME Configuration) settings, described in the "Disabling Changes on GNOME" annoyance earlier in this chapter.

1.11.5. KDE Sound Management

There are three tools associated with sound management on the KDE desktop, at least if you're looking for tools functionally equivalent to the GNOME Sound Preferences tool. They include the following:

Sound System Configuration: You can start the KDE Sound System Configuration tool with the kcmshell arts command. It includes two tabs. The General tab allows you to enable the sound system and manage its relative priority. The Hardware tab allows you select and configure the audio and MIDI devices.
System Bell Configuration: You can start the KDE System Bell Configuration tool with the kcmshell bell command. If you activate the system bell, it supersedes settings in the System Notifications Configuration tool.
System Notifications Configuration: If you haven't activated the KDE system bell in the System Bell Configuration tool, you can customize sounds for different events. You can start the KDE System Notifications Configuration tool with the kcmshell kcmnotify command. It allows you to configure and customize sounds in several categories.

These tools are straightforward; they directly configure the sound settings on a per-user basis. Changes are written to several files in each user's ~/.kde/share/config directory.