Linux audio developers

Linux audio software

Source code

All these projects are supplied as source code for you to install, inspect, modify and redistribute under the GNU GPL.

JACK Bitmeter

The utility previously known as JACK Bitscope returns with a new name but very few other changes, as JACK Bitmeter Version 1.2. Documentation is included with the package and is also available online

GL Mixer

A new release of GL Mixer has been uploaded. Version 0.3 of GL Mixer needs GtkGLext and of course JACK, and offers further improvements over 0.2


The current pre-release of Demolition is: Version 0.9.
If you don't know what this is, you probably don't need it. However there is or will soon be documentation online for it.

NJL plugins

Yet another collection of LADSPA plugins named after the author's initials. It's traditional after all. The current release is: Version 0.2.1.


The current release of XMMS LADSPA is: Version 1.1.
Please direct questions about XMMS LADSPA to

What is it?

XMMS LADSPA is an Effect for XMMS that provides (some of) the power of the Linux Audio Developer's Simple Plugin API to your everyday MP3 and all-around media player. It's Free Software of course, under the GNU General Public License.

Older versions of XMMS support only a single Effect, such as Echo and it has to be written specifically for XMMS. Even in newer versions only one copy of each Effect plugin can be running and very few good quality Effects exist for XMMS anyway. With XMMS LADSPA you can use any number of audio processing plugins written to the LADSPA specification, which includes all the GPL software at maintained by Steve Harris.


Obviously you're mostly interested in what this software sounds like, but the possibilities are mind-blowing even in XMMS so you'll have to be content with a picture of what it looks like. Here is a full desktop screenshot. Yes, the software in that shot is a development version on the road to 0.3 release, but rest assured that the version you're downloading looks much the same (most changes are behind the scenes)

9 December 2006

GL Mixer has been updated to version 0.3, featuring smoother and more natural pan and fader behaviour, more keyboard shortcuts, some view presets, and a convenient user interface for sending output audio to the right JACK application or hardware device.

New releases now have the new email addresses in their accompanying documentation. The old addresses will continue to work if you haven't needed to upgrade.

30 July 2006

This is the new home of my Linux audio software. My email will be moving here too, but for now continue using the previous address for any bug reports etc.

2 April 2006

This page (and my other software pages) will soon move elsewhere, but hopefully there will be some considerable warning before they step working altogether.

GL Mixer has been updated to version 0.2, it now has more keyboard shortcuts and configurable colors and labels for the mixer blobs.

13 August 2005

New home for this web page, and a new name for my JACK diagnostic tool, which is now called JACK Bitmeter, see above/ left.

25 June 2005

One line fix the previous version makes for njl-plugins-0.2.1.tar.gz. If you had no trouble with the previous version you needn't download this one, on the other hand if risset_1924 produced white noise for you then here's the fix.

21 March 2005

One new LADSPA plugin for njl-plugins-0.2.tar.gz. risset_1924 implements Jean-Claude Risset's continuously rising tone, an interesting aural illusion. The amplitude and "core" frequency can be varied, as can the direction and rate of apparent change in tone.

16 March 2005

Version 1.1 of XMMS LADSPA fixes a previously unreported bug where the state restoring code from 1.0 can crash XMMS. All users of previous versions are recommended to upgrade.

2 March 2005

Three LADSPA plugins in the first version of njl-plugins. There's a white noise source that's evenly distributed over the IEEE single precision 32-bit floating point range to 0dB (which is +/- 1.0 in LADSPA), and a more conventional white noise source with variable precision. It's hard to hear what either of them do, but you can see it in JACK bitscope.

Lastly there's an experimental effect which simulates other types of floating point representation with reduced precision. For 16-bit "half precision" try 5 bit exponent and 10 bit mantissa, you'll probably find it hard to detect this change; for 8-bit "quarter precision" try 3 bit exponent and 4 bit mantissa, or else 4 bit exponent and 3 bit mantissa (personally I think the latter sounds a lot better).

10 May 2004

I've just tested GtkGLext 1.0.6 and found that it fixes a minor problem seen in the GL Mixer, namely the crash on closing. Therefore GtkGLext 1.0.6 is now the minimum recommended version for GL Mixer.

I've been asked by the people behind the digital oscilloscope Bitscope to rename JACK Bitscope. So look out for a new name, meanwhile I've linked to their site.

6 April 2004

Version 1.0 of XMMS LADSPA is now available. The main change from version 0.7 is the saving & restoring of state, which was asked for by Eugene Miller and Khadiyd Idris (who also sent a partial implementation that was influential in my eventual design) and many more.

30 March 2004

Lots going on behind the scenes, but the JACK bitscope some of you were waiting for is now available.

30 November 2003

GL Mixer makes it out the door in time for Christmas. There's a lot missing from this, but it already looks pretty cool.

5 April 2003

A pre-release of demolition is now available. See the sidebar. Demolition is a tool I wrote to test LADSPA plugins. This is mostly for LADSPA plugin developers, but it's also handy if you maintain a LADSPA host and you suspect that a certain plugin doesn't play by the rules.

14 February 2003

Version 0.7 of XMMS LADSPA is now available. This version works with current XMMS CVS as well as previously released versions. There are a few other minor tweaks. Get this if you're planning on running the new version of XMMS when it's finished, or if you test XMMS from CVS.

19 July 2002

Version 0.6 of XMMS LADSPA is now available. This includes the new default hints feature, and some minor tweaks. Sorry, I'm very busy so other features that have been requested will have to wait a bit longer.

20 May 2002

Version 0.4 of XMMS LADSPA is now available. This adds two little changes to improve the dual-list GUI. Firstly you can now double click on a plugin name to add an instance of that plugin. Secondly you can re-order running plugin instances live, just by dragging them up or down in the list.

Update! Version 0.5 replaces XMMS LADSPA 0.4, there is no functional difference but I forgot to bump the displayed version number in 0.4 so let's just forget about 0.4 altogether.

29 April 2002

Version 0.3 of XMMS LADSPA is now available. The most notable improvement for most users is that the control UI for plugins has been tweaked to be more usable on a wider range of plugins. Also control outputs (floating point values from the plugin) are now correctly displayed in the GUI for that instance.

XMMS LADSPA now also searches LADSPA_PATH for plugins.

13 April 2002

First version of this web site, versions 0.1 and 0.2 are already in the wild, and I'm making progress on version 0.3 (just broke off from writing it to create a screenshot for this page, and then I remembered I hadn't written the page yet...)

Read the README inside for caveats, and note that this software doesn't do anything unless you have LADSPA plugins installed. Try the LADSPA website or the ones from written by Steve Harris.