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See also:


arecord filename.wav


S/PDIF is IEC 60958 type II (IEC 958 before 1998)

Some more programs

  • audiolink
  • The, for the command line, audiotools package
  • multimedia-audio-utilities package


aumix -v q -b q -c q -i q -l q -m q -o q -p q -r q -s q -t q -w q -W q -x q -1 q -2 q -3 q show the status of all devices aumix can handle:

-vvol 50, 50
-bbass 0, 0
-ccd 0, 0
-iigain 100, 100
-lline 0, 0
-mmic 0, 0
-oogain 0, 0
-pspeaker 0, 0
-rrec 0, 0
-ssynth 0, 0
-ttreble 0, 0
-wpcm 0, 0
-Wpcm2 0, 0
-xmix 0, 0
-1line1 0, 0
-2line2 0, 0
-3line3 0, 0
aumix -qdig1 100, 100As mentioned in the man page does not work (for us). We expeceted the levels for all items


Mute the sound for three minutes:

amixer set Master mute 1> /dev/null; sleep 3m; amixer set Master unmute 1> /dev/null; xmessage -buttons OK -default OK -timeout 20 "Sound is back again!"

Pulse Audio

PulseAudio is a network-capable sound server program
Debian on PulseAudio


CLI tools and man pages

default.paPulseAudio Sound Server Startup Script
pacmdReconfigure a PulseAudio sound server during runtime
pactlControl a running PulseAudio sound server
pulse-cli-syntaxPulseAudio Command Line Interface Syntax
pulseaudioThe PulseAudio Sound System

VU meter

The “Pulse Audio Volume Meter” is a GUI vu meter program. In the terminal it is called pavumeter. If you do not need it your can uninstall it. Do aptitude uninstall pavumeter

Volume Control

This is part of PulseAudio
In this context pavucontrol = Volume Control = “Audio Mixer…“
If you want to work in a terminal you can use alsamixer. It has some other, different, settings
P.M. :

  • alsaplayer - plays various sound files
  • alsactl - advanced controls for ALSA soundcard driver. root or sudo needed
  • alsabat, alsaloop, alsatplg, alsaucm
  • Root or sudo needed: alsabat-test, alsa-info

This is the pavucontrol program which is part of the PulseAudio sound server system

The pavucontrol program has this icon. You can find it in or add it to the system tray. Left clicking brings you to some settings. You can also open Volume Control, here called “Audio Mixer…”, by right clicking on icon. “Audio Mixer…” is on the bottom line

The slider in the Playback tab can only have the same or a lower position then the slider in the Output Devices tab. If you slide the slider in the Playback tab above the value of the slider in the Output Devices tab the slider in the Output Devices tab will follow the slider in the Playback tab. They then have the same level set

We do not advice to use this icon. It can be confusing when you control the volume with it. We advice to use the Volume Control program in its own window

Analog Stereo Duplex: Both Input and Output are active
The Volume Control window has 5 tabs:

PlaybackA list of programs producing soundLike mpv and Firefox. For every program which is playing sound or is paused or has, like Firefox can have, a tab open which plays, is paused and / or muted or has played sound you can find an entry here. Programs can disappear from the list when they are done playing the sound or are closed. Here you can also select on which Output Device (third tab, Output Devices) the sound should be played
RecordingHere you can see the programs which are running and can record audioYou can select the device of which the audio should be recorded from from the roll down menu on the right side
Output DevicesA list of the hardware devices in or on the computerLike a soundcard on the motherboard, a soundcard in a PCI or PCIe slot on the motherboard or an USB soundcard. Here you can also select on which soundport the sound is offered like Speakers, Line Out (mostly a 3,5 mm jack connector) or Headphones (mostly a 3,5 mm jack connector). Advice: Set the volume here to 100% and adjust the volume in “Playback” to you needs
Input DevicesA list of the hardware devices which can record audio. It is possible that a device also has a Monitor functionCheck if the device is unmuted if you want to use it
ConfigurationA list of devices. Here you can select the output modus or switch the device offSome options which can be found here: Off, Analog Stereo Duplex, Analog Stereo Input, Analog Stereo Output

Setting the volume

This can be done in or on

  • the amplifier
  • the computer
    • In the tab Playback with the slider of the device or stream which is playing
      • When you set the volume with the tray icon the volume of all the channels in this tab is set accordingly. So it is better not to use the tray icon for volume control if you have more then one device or stream playing or open
    • In the tab Output devices with the slider of the device or stream which is playing
      • This is also what you see and can adjust from the tray icon

Audio mixers and Interfaces

In general:
Audio mixers and Audio Interfaces with an USB connection do not deliver enough signal level
On a mixer much more signal level can be obtained via the analog, Main Out, connection

The advantage of an audio interface can be a higher sampling rate and a nicer box. A mixer has more options and a higher analog signal output


The FX signal from the individual channels on a mixer is added up in the Fx send output of the mixer. From there it can be connected to an external effects unit which is most commonly a reverb unit. You can have a look at this video on Youtube to get an idea

Pad button

The PAD button will reduce the input gain on your channel by a fixed amount of usually 20-26dB. This prevents distortion by loud input signals because which can overload the pre-amplifier and thereby cause clipping of the signal
In schematic

Input > PAD circuit > Pre-amplifier > The other parts of the mixer

Solving a headphone issue
Change default Pulseaudio profile to analog stereo duplex
aplay card and device selection with aplay -l and aplay -L

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audio.txt · Last modified: 22-06-2022 22:25 by wim