Mixers are a convenient way of controlling the volume and balance of the computer's sound output and input. The main differences in the various mixers are the interfaces. Select one that meets your needs.


Generally, it is advisable to open a mixer application prior to opening other sound applications. Use the mixer to test and adjust the control settings for the input and output of the sound card. Some sound cards may not allow simultaneous access from multiple applications. If a sound application freezes, this might be the cause.


If you have multiple sound cards, gamix provides a set of controllers for each card. Slide the control sliders to set the levels as desired.

Figure 18.1. The Mixer gamix

The Mixer gamix


QAMix is a mixer with a QT interface. If necessary, the application interface can be configured in a flexible way in an XML file. All parameters can be controlled via MIDI. On start-up, the application first searches the directory ~/.qamix for an XML file corresponding to the name of the ALSA driver of your sound card. If such a file does not exist, it searches the same directory for the file default.xml. If this file does not exist either, the program continues its search in the directory /usr/share/qamix.

If you have several sound cards, select the desired card with the parameter -c. hw:0 stands for the first sound card, hw:1 for the second, and so on. The parameter -g can be used to specify a file for the XML description of the application interface explicitly. Detailed information about the XML format is available in the directory /usr/share/doc/packages/qamix.

Figure 18.2. The Mixer QAmix

The Mixer QAmix


KMix is the KDE mixer. It provides a convenient and familiar interface for KDE users. It can also be integrated into the KDE panel.

The GNOME Mixer Applet

If you use GNOME, this applet provides a convenient volume control that can be integrated in a panel. To add it to a panel, right-click the panel then select Add to Panel -> Multimedia -> Volume Control. Right-click the volume control applet then select Run Volume Control to access the more advanced mixer functions.


alsamixer can be run from the command line without the X environment. The application is operated with the cursor keys. Use Q, W, E, Y, X, and C to set different levels for the left and right channels. M mutes single channels. In this case, MM appears above the muted controller. To terminate alsamixer, press Esc.


The look and feel of alsamixer depends on the type of sound card used. The following description refers to the widely-used AC97 standard for mixer functionality. If your sound card does not comply with this standard, some features may not be supported. The mixer Envy24 should be used for sound cards equipped with the Envy24 (ice1712) chip.

The basic controls for sound output are Master, PCM, and CD. Master sets the master volume. PCM and CD control the respective weighting of the PCM and audio CD channels.

Determine the recording source by pressing Space. The capture controller regulates the input amplifier. Whether the Line controller or the MIC controller is used depends on the recording source.

For more information, enter man alsamixer. alsamixergui is a mouse-operated variant of alsamixer with a graphical interface.

Mixer Parameters of Soundblaster Live! and Audigy

Apart from the parameters of the AC97 standard, there are many additional options for Soundblaster Live! and Audigy cards. The controls AC97, Wave, and Music are used for playback. AC97 can be used to adjust the level of the AC97 mix. This mix also receives input from the line, mic, and CD signals. Wave adjusts the level of the PCM channels. Music controls the volume of the internal wavetable synthesis of MIDI data.

Apart from the Capture parameter for recordings, the AC97 Capture control is used to control the level of the AC97 recording sources. Furthermore, Wave and Music can be selected as recording source. This internal loopback capture can be activatedin the AC97 standard by selecting the Mix control as recording source.

The Mixer for the Sound Chip Envy24

Figure 18.3. Monitor and Digital Mixer of envy24control

Monitor and Digital Mixer of envy24control

envy24control is a mixer application for sound cards using the Envy24 (ice1712) chip. Start this mixer with SuSE -> Multimedia -> Sound or from the command line with envy24control &. The flexibility of the Envy24 chip can result in varying functionalities in different sound cards. The latest details on this sound chip are available in /usr/share/doc/packages/alsa/alsa-tools/envy24control.

Monitor and Patchbay of envy24control

The Monitor Mixer of envy24control shows the signal levels that can be mixed digitally in the sound card. The signals designated as PCM Out are generated by applications that send PCM data to the sound card. The signals of the analog inputs are shown under H/W In. The S/PDIF inputs are shown to the right. The input and output levels of the analog channels must be set under Analog Volume.

Figure 18.4. The Patchbay

The Patchbay

Use the Monitor Mixer sliders for digital mixing. The respective levels are displayed in the Digital Mixer. For each output channel, the Patchbay contains a row of radio buttons for selecting the desired channel source.

Analog Inputs and Outputs

Adjust the amplification for the analog-to-digital and digital-to-analog converters under Analog Volume. The DAC sliders are used for the output channels and the ADC sliders are used for the input channels. Use the radio buttons to switch the levels between +4 dBu and -10 dBV. The first setting is intended for audio professionals. The latter is for private purposes.

Figure 18.5. Mixer for Analog Inputs and Outputs

Mixer for Analog Inputs and Outputs

Configuration of the S/PDIF Channels

The S/PDIF channel settings are made under Hardware Settings. The Envy24 chip reacts to volume changes with a delay that can be configured with Volume Change.

Figure 18.6. Configuring the S/PDIF Parameters with envy24control

Configuring the S/PDIF Parameters with envy24control