SoX Sound Exchange Audio Tool

SoX (Sound eXchange) is a cross-platform command-line audio editor and processing tool for converting, manipulating, and generating audio files. Originally developed by Lance Norskog in 1991 as a simple audio format converter, SoX has evolved into a comprehensive digital audio processing suite maintained by Chris Bagwell and others since 1999. Key features: reads and writes over 30 audio formats including WAV, AIFF, FLAC, OGG Vorbis, MP3, AAC, ALAC, Opus, MP2, raw PCM, and many obscure formats like VOC, AU, SND, and GSM. Audio effects pipeline applying multiple effects in sequence via command-line, including filters (lowpass, highpass, bandpass, bandreject, allpass), dynamics (compressor, expander, normalize, fade, gain), pitch shifting, tempo changing, reverb, echo, chorus, flanger, tremolo, vibrato, and noise reduction. Sample rate conversion with high-quality resampling algorithms including linear, cubic, and polyphase filters. Audio synthesis generating test tones, sine waves, noise (white, pink, brown), and complex waveforms for testing and calibration. Audio analysis including statistics (RMS, peak, DC offset), spectrograms, and frequency analysis. Batch processing via shell scripting for converting or processing large numbers of files. Multi-channel audio support including stereo, 5.1 surround, and arbitrary channel counts. Recording from audio input devices and playback to output devices on supported platforms. Combine and split operations for merging and separating audio files. Spectrogram generation and export. Libre software under GPL and LGPL. Used in audio production, broadcasting, speech research, audio forensics, and automated audio processing pipelines.