Tape Resampler, a new Studio One 5 feature, replicates an “old school” time-stretch technique that varied pitch and tempo simultaneously and proportionately. Today’s DSP can change pitch and tempo independently, which is cool. But the price you pay is artifacts, because when changing tempo or pitch, you need to either delete or add data.
With resampling, the data stays the same—so there are no artifacts, and the sound is natural. Although extreme speedups give the “Chipmunks” sound and extreme slowdowns evoke Darth Vader on tranquilizers, subtler speed changes were used all the time with tape. It was common to speed up a master tape by a few per cent to give the tempo a slightly faster, “peppier” sound, as well as some added brightness. (If you’ve ever tried to play along with a song that was several cents sharp, it was probably sped up a bit.)
The manual mentions using Tape Resampler to fit loops to tempo (assuming accurate pitch isn’t crucial), but there’s another application that at least to me, is worth the update price by itself. With tape, it was common to slow the tape down or speed it up, play along with the part, and then return the speed to normal. This produced a timbral and formant shift, and was popular for background vocals. For example, if a song was in the key of A, you’d slow down to the key of G, sing along with it in G, then return the tape to normal. The vocal would have a brighter formant change that often worked well. This could also help you hit notes that were just out of your range. (We covered similar techniques in the blog post Varispeed-Type Formant Changes, but because they used DSP, at least some artifacts were unavoidable.)
The Handy Transposition Chart
|Semitones||Pitch Up||Pitch Down|
Figure 1: The overdub is being raised two semitones.
Note that the transpose numbers relate to the 12th root of 2. This irrational number (its numerical value has been taken out to over twenty billion decimal digits, but it still doesn’t repeat!) sets the ratio between semitones of the even-numbered scale. Fortunately, three significant digits covers our needs.