This module amplifies or attenuates the signal. The primary envelope determines by how much the signal is attenuated, from zero to twice as loud.

This module zeroes those parts of the signal that are below a certain treshold for a given duration. The Delete option toggles whether the relevant section in the signal should be zeroed or deleted. The Gang tracks option toggles whether each track should be processed separately, or whether the intersection from all selected tracks should be used. Finally the Invert option inverts the meaning of the operation, selecting noise rather than silence.

This module shrinks the selection to the nearest zero points. This is mostly useful to prevent clicks in a looped sample.

This module implements a very simple bandpass filter. It was lifted from the sox audio tool distribution mostly as a curiosity. Much better and more versatile filters are available through the GLADSPA plugins module.

This module removes some digital clipping artifacts from material that was recorded too loud. It is very naive but still I find it works rather well.

This module implements a simple digital delay. The Duration parameter controls the duration of each delay in the time units as given by the time control bar. This parameter is controlled by the primary envelope. The Times parameter controls the number of delays. The Decay parameters controls the rate of decay. This parameter is controlled by the auxiliary envelope.

This module fades in the signal. The primary envelope controls the attenuation factor.

This module fades out the signal. The primary envelope controls the attenuation factor.

This module implements support for the LADSPA plugin architecture.

You must install some GLADSPA plugins to use this module, these can be obtained from http://www.ladspa.org. Before starting GNUsound make sure the LADSPA_PATH environment variable points to the location where your plugins are installed. If the LADSPA_PATH is not defined then GNUsound will search /usr/local/lib/ladspa for plugins.

The interface for this module consists of a window that is split in two halves: the left half contains the available plugins, and the right half contains the parameters for the selected plugin.

When the list of plugins is active, you can press a key to jump to the first plugin whose name starts with that letter.

The right half of the window has sliders to set the parameters for the plugin. You can use the Env1 and Env2 buttons to assign a parameter to the corresponding envelope. The envelope modifies the parameter value in the following way: if the envelope value is 0, then the parameter value is the parameter value set by the user. If the envelope value is between 0 and 1, then the parameter value is between the user selected parameter value and the maximum parameter value. Finally if the envelope value is between 0 and -1, then the parameter value is between the user selected parameter value and the minimum parameter value.

An envelope assigned to a GLADSPA parameter does not change that parameter every sample; rather the signal is processed in blocks and the envelope value applies to an entire block. The size of these blocks can be changed in the configuration file (the ladspa_segment_time parameter). The default value for this parameter is 0.01 seconds.

This module implements a very simple lowpass filter. It was lifted from the web and is included mostly as a curiosity. Much better and more versatile filters are available through the GLADSPA plugins module.

This module mixes the signal from the second selected track into the first. The primary envelopes on the selected tracks specify the contribution of each track to the final signal.

This module maximizes the peak amplitude of the selected region. If the selection spans multiple tracks, then the global peak for the selected tracks is maximized.

This module changes the sampling rate of the selected audio. Depending on whether you have libsamplerate installed it offers one or more methods of doing so, with varying quality/speed tradeoffs. The primary envelope controls the rate.

This module reverses the selected data.

This module implements a simple tone generator which can also be used to generate silence. The primary envelope controls the amplitude while the auxiliary envelope controls the frequency.

From version 0.7 onwards, GNUsound uses a modular playback/record architecture. This makes it easier to support different audio APIs.

From version 0.7 onwards, GNUsound uses a modular file load/save architecture. This makes it much easier to add support for new file formats.

Which file drivers are available depends on your system configuration at build time. If you want to take advantage of the improved file format support you will need to install the software mentioned below prior to building and installing GNUsound.

When loading a file, GNUsound tries to autodetect the file type by having each driver probe the file in turn, until one of the drivers recognizes it.

This is not a waterproof strategy: it's not always possible to determine the file type with 100% certainty. In particular the LAME and FFmpeg drivers can sometimes misidentify files. This can lead to garbage being read or even crashes.

To minimize the chances of this happening, the order in which the file is probed by the drivers is important. They need to be ordered in such a way that the driver with the highest probability of getting confused gets to probe last.

The default probe order was determined through some experimentation to give the best results, but if necessary it can be changed through the file.drivers.probe_order preference.