ALSA Mixer | Documentation Skip to main content Search form Search 2021/22 students COVID-19 Computing Help Contact us (external) Contact us New to Informatics? Computing accounts Services Mail Printing Network Platforms Software Guides and HOWTOs Remote working Learning Technology Policies and guidelines Projects Student laptops Teaching Raising queries and escalation FAQ You are here Home ALSA Mixer AlsaMixer is one of the least deceptive of the volume control apps available on DICE. However operating it is still not entirely straightforward. Launch AlsaMixer in a terminal using $ alsamixer. This starts the mixer with your default ALSA sound card. You'll see something like the following:
┌──────────────────────────────────────── AlsaMixer v1.2.2 ────────────────────────────────────────┐
│ Card: HDA Intel PCH F1: Help │
│ Chip: Conexant CX20632 F2: System information │
│ View: F3:[Playback] F4: Capture F5: All F6: Select sound card │
│ Item: Master [dB gain: -12.00] Esc: Exit │
│ │
│ │
│ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ │
│ │ │ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ │
│ │ │ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ │
│ │ │ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │ │ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │ │ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ →
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ │
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ │
│ │▒▒│ │▒▒│ │▒▒│ │ │ │▒▒│ │ │ │ │ │
│ ├──┤ ├──┤ ├──┤ ├──┤ └──┘ └──┘ └──┘ ┌──┐ ┌──┐ ┌──┐ │
│ │OO│ │OO│ │OO│ │MM│ │MM│ │OO│ │OO│ │
│ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘ │
│ 61 100<>100 100<>100 0<>0 98<>98 0<>0 0<>0 │
│ < Master >Headphon Headphon Speaker+ PCM Line Boo Mic Boos S/PDIF S/PDIF 1 S/PDIF 2 │
│ │
└──────────────────────────────────────────────────────────────────────────────────────────────────┘
At the top, note the status information. Make sure that 'Card' says something sensible (usually Intel something, but whatever makes sense for that machine). Also make sure you're adjusting the Playback or Capture (record) views as appropriate, to avoid confusion: you can choose between these with Tab. You can move between alsamixer lines with the arrow keys, as you'd expect: your current selected line is , and its full name is shown in the "Item" status line at the top. Note the ">" symbols on the right border, indicating that further volume lines are hidden off-screen. You can adjust volume on these lines with up and down, and toggle their mute status with 'M' key. Note, on a typical DICE machine, the multiple 'Master' volume lines, the 'OO' (On) and 'MM' (Mute) states, and the lines without a volume bar (notably the second of the 'Headphon' entries). Typically important volume lines: Master: all output (apart from Master Mono) will depend on this, headphone or otherwise. Shouldn't typically be muted. Master Mono: this will control the built-in speaker on most hardware. Shouldn't typically need to be muted unless external speakers are plugged in, or the headphone jack sense isn't doing its job. Headphone: often this controls only the headphone socket on the front of the PC, not at the back. Generally should not be muted. Headphone Jack Sense: when enabled (OO) this line should disable other sources of sound when headphones are plugged into the headphone socket. PCM: 'regular' audio (sound files, videos, etc.) is processed through this line. This should never be muted (unless you don't want to hear audio). Unless things are very quiet you should also take care to keep this at a gain level of no more than 0dB (on this line, alsamixer represents amplification in red, so about 3/4 volume represents the highest unamplified level). External Amplifier: enabled (OO) if you are using external, powered speakers (not headphones); disabled (MM) otherwise. Final note: Quit using Esc - for some reason this is not instantaneous but be patient! Don't impatiently stab at q, as I tend to do: q/z adjust the left-channel volume up and down by one unit, and will leave you feeling a little unbalanced! Troubleshooting No sound Check that 'Master', 'Master Mono', and 'PCM' are all unmuted and above minimum volume. Distorted sound Check that the PCM and any similar lines do not have gain above 0dB. Sound comes out of the front speaker when it shouldn't Check that 'Headphone Jack Sense' is ON (showing OO): toggle with the 'M' key. Failing that you can mute the internal speaker by muting (with 'M') the 'Master Mono' line. Error starting alsamixer: ... For example:
$ alsamixer
alsamixer: function snd_ctl_open failed for default: No such device
This suggests that there's no sound card available. You can try opening an alternative device using
$ alsamixer -c#
where # is a number (0 is the default as confirmed by the alsacard command). Mixer doesn't control any volume levels You're probably using an external / alternative sound card. Try changing the card, as in the above question. You can also select an ALSA device by name, e.g.
$ alsamixer -c usb
Also check that you've not slipped into 'Capture' or 'All' views: press Tab and make sure you're on Playback so that you can only adjust playback lines. Last reviewed: 07/06/2021 System Status Home dirs (AFS) Network Mail Other services University services Scheduled downtime Choose a topic - Select - accounts ACL AFS Android Appleton Tower assessment authentication AV azure backups bash beginner blackboard blog cabal cdt chrome Chrome Remote Desktop cloud cluster CodeGrade Collaborate commercialisation conda connectivity contact corpora cosign coursework CUDA CVS Cygwin data protection data safe haven database datashare datastore datasync datavault Debian desktop development DICE display managers DNS Dropbox ease ECDF emacs email encryption energy environment equipment escalation events exams exFAT firefox firewall firewall self-managed flexlm floorbox forms GDPR gem Gerrit ghc Git GNOME GPFS GPU groups guides hadoop haskell help homepages howto https hybrid ifile ifriend ILCC ILCC GPU inactivity Informatics Forum installation iOS java Jupyter KDE kerberos knowledge management kvm laptops latex ldap Learn Learning Technology lecture recording legacy Leganto licensing linux logging long-running job MAC address macOS mailing lists make map/reduce maple mariadb matlab MDP Media Hopper microsoft mirrors mounting mysql network network ports NTP numerical computing nvidia office365 online learning online meetings OpenVPN overleaf panopto passwords PDF phishing plugin policies poster PostGIS PostgreSQL power power-saving print credit printing privacy projects prolog proxy public keys purchasing putty python quota reading list realcrypt records remote working Resource Lists root RPMs RT ruby safari samba scanning school database scl screenlock screensaver SDXC security self-managed servers shell SL7 sleep slurm smtp software software collections solstice spam spnego ssh ssl stack storage subnet sudo support surveys SVN teaching teaching exams Teams template tesla tex theon time tls Top Hat topcoat training truecrypt Turnitin Ubuntu UPS USB veracrypt video conferencing video-conferencing Virtual DICE virtualbox virtualisation virus visitor accounts vlan VPN wake web webmark webots wepresent wiki window managers Windows wireless Your University Login Zoom Feedback To leave feedback or other suggestions about this website, please see our contact page. A statement on Data Protection and Interception on Informatics Managed Systems. Unless explicitly stated otherwise, all material is copyright The University of Edinburgh. Login to this site
