Tascam TA-1VP Owner's Manual

8 TASCAM TA-1VPReally Easy To Use• No scrolling though endlessmenus to find the parameter you want. Virtually everymajor function is only a single button press away.Auto-Tune Pitch CorrectionIn 1997, Antares first introduced the ground-breakingAuto-Tune Pitch Correcting Plug-In for ProTools™(eventually followed by most other plug-in formats). Herewas a tool that actually corrected the pitch of vocals andother solo instruments, in real time, without distortionor artifacts, while preserving all of the expressive nuanceof the original performance. Recording Magazine calledAuto-Tune a “Holy Grail of recording.” And went on to say,“Bottom line, Auto-Tune is amazing… Everyone with aMac should have this program.”The TA-1VP's Auto-Tune module is a licensed hardwareimplementation of Antare's Auto-Tune Evo pitchcorrecting software. Like Auto-Tune, the TA-1VP employsstate-of- the-art digital signal processing algorithms(many, interestingly enough, drawn from the geophysicalindustry) to continuously detect the pitch of a periodicinput signal (typically a solo voice or instrument) andinstantly and seamlessly change it to a desired pitch(defined by any of a number of user-programmablescales).A little bit about pitchPitch is typically associated with our perception ofthe “highness” or “lowness” of a particular sound. Ourperception of pitch ranges from the very general (thehigh pitch of hissing steam, the low pitch of the rumbleof an earthquake) to the very specific (the exact pitch ofa solo singer or violinist). There is, of course, a wide rangeof variation in the middle. A symphony orchestra playinga scale in unison, for example, results in an extremelycomplex waveform, yet you are still able to easily sensethe pitch.The vocalists and the solo instruments that the TA-1VP isdesigned to process have a very clearly defined qualityof pitch. The sound-generating mechanism of thesesources is a vibrating element (vocal chords, a string, anair column, etc.). The sound that is thus generated canbe graphically represented as a waveform (a graph of thesound’s pressure over time) that is periodic. This meansthat each cycle of waveform repeats itself fairly exactly, asin the periodic waveform shown in the diagram below:Because of its periodic nature, this sound’s pitch can beeasily identified and processed by the TA-1VP.Other sounds are more complex. This waveform:is of a violin section playing a single tone. Our earsstill sense a specific pitch, but the waveform does notrepeat itself. This waveform is a summation of a numberof individually periodic violins. The summation is non-periodic because the individual violins are slightly out oftune with respect to one another. Because of this lack ofperiodicity, Auto-Tune would not be able to process thissound.Some pitch terminologyThe pitch of a periodic waveform is defined as the numberof times the periodic element repeats in one second.This is measured in Hertz (abbreviated Hz.). For example,the pitch of A3 (the A above middle C on a piano) istraditionally 440Hz (although that standard varies by afew Hz. in various parts of the world).Pitches are often described relative to one another asintervals, or ratios of frequency. For example, two pitchesare said to be one octave apart if their frequencies differby a factor of two. Pitch ratios are measured in units calledcents. There are 1200 cents per octave. For example, twotones that are 2400 cents apart are two octaves apart. Thetraditional twelve- tone Equal Tempered Scale that is used(or rather approximated) in 99.9% of all Western tonalmusic consists of tones that are, by definition, 100 centsapart. This interval of 100 cents is called a semitone.How Auto-Tune detects pitchIn order for Auto-Tune to automatically correct pitch, itmust first detect the pitch of the input sound. Calculatingthe pitch of a periodic waveform is a straighforwardprocess. Simply measure the time between repetitions ofthe waveform. Divide this time into one, and you have thefrequency in Hertz. The TA-1VP does exactly this: It looksfor a periodically repeating waveform and calculates thetime interval between repetitions.The pitch detection algorithm in the TA-1VP is virtuallyinstantaneous. It can recognize the repetition in a periodicsound within a few cycles. This usually occurs beforethe sound has sufficient amplitude to be heard. Used incombination with a slight processing delay (no greaterthan 4 milliseconds), the output pitch can be detectedand corrected without artifacts in a seamless andcontinuous fashion.The TA-1VP was designed to detect and correct pitchesup to the pitch C6. If the input pitch is higher than C6,the TA-1VP will often interpret the pitch an octave lower.This is because it interprets a two cycle repetition as a onecycle repetition. On the low end, the TA-1VP will detectpitches as low as 42 Hz. This range of pitches allows2 – Introducing the TASCAM TA-1VP Vocal Producer