Baudline is a time-frequency browser designed for scientific visualization of the spectral domain. Signal analysis is performed by Fourier, correlation, and raster transforms that create colorful spectrograms with vibrant detail. Conduct test and measurement experiments with the built in function generator, or play back audio files with a multitude of effects and filters. The baudline signal analyzer combines fast digital signal processing, versatile high speed displays, and continuous capture tools for hunting down and studying elusive signal characteristics.
eXtace is a visual sound display/analysis program. It requires Esound (esd) for its audio source. It includes various fast fourier transforms of the audio data in realtime. Its displays include a 3D wireframe flying landscape, a 3D textured flying landscape, a 16-256 channel graphic EQ, three types of scopes, a 3D "spike" flying landscape, and two forms of spectragrams. The 3D traces can be picked up, manipulated, and displayed at nearly any angle. eXtace also features a 3D direction control widget for controlling the angle and speed at which the trace runs away and a gradient/colormap editor for changing the colormap to suit your needs. No OpenGL is required.
HASAS (HydroAcoustic Signal Analysis System) is a modular system for passive sonar signal analysis. It can be used for biological research or surveillance, for example. The soundcard is used as input device, and it currently includes all the very basic functionality; beamformed audio, direction finding, level histogram, LOFAR/DEMON (narrowband spectrogram), wideband spectrogram, and raw audio.
MPEG Maaate (MPEG audio analysis toolkit) is a C++ toolkit to parse and analyse audio data in the frequency domain, e.g. analysing MPEG-1/2 Layers 1-3 audio files in the compressed domain. It makes the encoded fields of an MPEG audio stream accessible and provides some content analysis functions like silence detection.
Sfront compiles MPEG 4 Structured Audio (MP4-SA) programs into efficient C programs that generate audio when executed. MP4-SA is a standard for normative algorithmic sound, which combines an audio signal processing language (SAOL) with score languages (MIDI and SASL). Under Mac OS X and Linux, sfront supports real-time, low-latency audio input/output and MIDI input. Under Mac OS X, sfront supports the creation of AudioUnit plug-ins. The documentation includes a book about SAOL programming.
The Snack sound extension adds commands for sound play/record and sound visualization, e.g. waveforms and spectrograms. It supports in- memory sound objects, file based audio, streaming audio, WAV, AU, AIFF, and MP3 file formats, synchronous and asynchronous playback. The visualization canvas item types update in real-time and can output postscript. New commands and file formats can be added using the Snack C-API.
Waterfall is a visualization plugin for XMMS. It's yet another spectrum analyzer, but it presents the data better, which makes it more interesting to watch. Most analyzers show a changing 2D bar graph of frequency vs. intensity. This one shows a scrolling 4D plot of frequency, time, intensity, and a configurable fourth variable mapped to hue.
WorldStation is a Java-based control panel to control the Ten-Tec DSP RX-320 shortwave receiver. The RX-320 is a "black box" radio which has no front-panel and is controlled via your PC's serial port. With an appropriate antenna, the RX-320 will allow you to listen to thousands of broadcasts from around the world. WorldStation features integrated Xbase frequency database support and advanced scanning to allow the user to visualize the radio spectrum.