What happened to the keyboard beep ?

A security update in November 2009 forced us to update the kernel to the one from Scientific Linux 5.4. This appears to have new sound "features", the two most obvious of which are:

  • The keyboard beep now comes through the soundcard instead of the speaker inside the computer.
  • Sound is no longer coming from headphones connected to the front socket of some, but not all, computers.

These problems appear to be a kernel bug: see https://bugzilla.redhat.com/show_bug.cgi?id=532444 and https://bugzilla.redhat.com/show_bug.cgi?id=525390. The official fix was available with RedHat Enterprise Linux 5.5 but does not fix the problem on our machines.

Until then I suggest that you run gnome-volume-control, check that you have enabled every option that might be relevant in the Edit/Preferences menu and try clicking and sliding everything you fancy.

playback diagram

The labels may not be appropriate and at least one pair of labels can be swapped:

switches diagram

If you find a setting which works for you please let me know.

(You can also try alsamixer if you want to run in a text window).

The keyboard beep can be disabled by muting the "PC Beep" option. I've heard rumours that the "PC Beep" slider controls the pitch rather the the volume, but my ears cannot confirm that.

For those of you who can't hear a beep, a (somewhat annoying) visible bell is available in xterm windows.

June 2005 version of the page below here

Most of this is now out of date.

Sound

The new computers can play music and other sounds.

These systems have lots of volume controls, and if any one is turned off you don't hear anything. Equally the speakers are quite loud and the walls are thin; if the volume is turned right up your neighbours will be able to listen to (and not just hear !) your music. Please keep it turned down or use headphones.

  • The speakers have an on/off button and a volume control.

The program kmix

picture of kmix
is a sound mixing desk; it shows volume controls for all the sound channels.

Confusingly the control marked Volume (the first green triangle) does nothing; instead PhoneOut(second from the right) is the master volume, and must be turned up.

Programs which generate sound may need one of the other sound channels turned up as well; most commonly the PCM, PCM2 (the blue waves) and the CD channel. Several programs provide their own control for one of these channels.

Playing music CDs

Use the program kscd for this. Alternatively you can use xmms with the command xmms /mnt/cdrom.

Playing mpeg .mp3s

Digital sound files in the MPEG .mp3 format can be found on the net, or created locally; Napster is one source. Some of these are made available with the permission of the copyright-holder, but others are pirated. Please respect copyright.

To play a single .mp3 file once you can use mpg123.

If you build up a collection of .mp3 tracks you may choose to use xmms which can store collections of tracks to be played in order. It also has a cute volume control which uses the wheel on your mouse.

Sound on the Web

The world wide web is not merely text and graphics; it contains sound too. Netscape often needs extra programs or configuration before you can hear it. If you give me instructions I would be very happy to add them here.

Appendix

MPEG Motion Picture Encoding Group - the committee that came up with the MPEG formats
PCM Pulse-Code modulation