frequency of every note by 3/2. Musical transposition preserves the ratios of the harmonic frequencies that determine the sound's timbre, unlike the frequency shift performed by amplitude modulation, which adds a fixed frequency offset to the frequency of every note. (In theory one could perform a literal pitch scaling in which the musical pitch space location is scaled [a higher note would be shifted at a greater interval in linear pitch space than a lower note], but that is highly unusual, and not musical.) Time domain processing works much better here, as smearing is less noticeable, but scaling vocal samples distorts the formants into a sort of Alvin and the Chipmunks-like effect, which may be desirable or undesirable. A process that preserves the formants and character of a voice involves analyzing the signal with a channel vocoder or LPC vocoder plus any of several pitch detection algorithms and then resynthesizing it at a different fundamental frequency. A detailed description of older analog recording techniques for pitch shifting can be found within the Alvin and the Chipmunks entry. In consumer software Pitch-corrected audio timestretch is found in every modern web browser as part of the HTML standard for media playback. Similar controls are ubiquitous in media applications and frameworks such as GStreamer and Unity. See also Beatmatching Dynamic tonality — real-time changes of tuning and timbre Pitch correction Scrubbing (audio) References External links Time Stretching and Pitch Shifting Overview A comprehensive overview of current time and pitch modification techniques by Stephan Bernsee Stephan Bernsee's smbPitchShift C source code C source code for doing frequency domain pitch manipulation pitchshift.js from KievII A Javascript pitchshifter based on smbPitchShift code, from the open source KievII library The Phase Vocoder: A Tutorial - A good description of the phase vocoder New Phase-Vocoder Techniques for Pitch-Shifting, Harmonizing and Other Exotic Effects A new Approach to Transient Processing in the Phase Vocoder PICOLA and TDHS How to build a pitch shifter Theory, equations, figures and performances of a real-time guitar pitch shifter running on a DSP chip ZTX Time Stretching Library Free and commercial versions of a popular 3rd party time stretching library for iOS, Linux, Windows and Mac OS X Elastique by zplane commercial cross-platform library, mainly used by DJ and DAW manufacturers Voice Synth from Qneo - specialized synthesizer for creative voice sculpting TSM toolbox Free MATLAB implementations of various Time-Scale Modification procedures PaulStretch, a