Time and Pitch effect
There are two effects in the Time and Pitch category: Automatic Pitch Correction and Pitch Shifter. Automatic Pitch Correction is designed for vocals and corrects the pitch of notes so that they are in tune. Pitch Shifter transposes audio upward or downward in pitch without affecting the tempo.
Automatic Pitch Correction
Pitch correction is intended for vocals whose pitch is slightly out of tune. This effect analyzes the vocal to extract the pitch, calculates how far off a note is from the correct pitch, and then corrects the note by raising or lowering the pitch to compensate.
However, be careful when you’re applying this effect; many vocalists deliberately sing some notes a little flat or sharp to add interest or tension to a vocal. Correcting these can remove a vocal’s “human” quality.
- Choose File > Open, navigate to the Lesson04 folder, and open the file OriginalVocal.wav. Don’t start playback yet.
- Click an effect insert’s right arrow, and choose Time and Pitch > Automatic Pitch Correction.
- Bypass the Automatic Pitch Correction effect, and start playback. Observe the correction meter on the right: The red band indicates how far off the pitch is from the ideal. When the meter moves up, the pitch is sharp. When the meter moves down (see screen shot), the pitch is flat. A centered meter indicates that the vocal is on pitch.
You need to know a vocal’s correct scale and key to use the Scale and Key options; choose these from the Scale and Key drop-down menus. If you do not know the Scale and Key, choose Chromatic from the Scale drop-down menu, which simply corrects to the nearest semitone. (The vocal is in D but uses a flatted 7th note that is not part of the major scale. So, choose Chromatic instead.) In most cases, Chromatic will do accurate correction.
- Set the Sensitivity slider to 200 to correct all notes. At lower Threshold settings, notes that are off-pitch by more than the pitch threshold will be unaffected.
- Start playback with Automatic Pitch Correction still bypassed. It’s a good idea to loop this example so you don’t have to keep clicking Play. Listen for a few iterations of the loop, and then enable the effect.
- Note how all the notes are on pitch. To compare, either bypass the effect or move the Sensitivity Fader to 0.
- Move the Attack slider to 10. This produces the fastest response, so the Automatic Pitch Correction will attempt to pitch-correct the vibrato. You’ll hear a warbling sound, so use a slow enough setting to allow the vibrato to change pitch naturally. A setting of 2–4 is a good compromise between correcting pitch rapidly on sustained notes but not affecting vibrato.
- Change the scale to Minor and Key to D. You’ll hear the vocal take on a more minor quality as notes are shifted to the appropriate pitches for a minor scale.
The Pitch Shifter can transpose an audio file up or down in pitch, but unlike some pitch-shifting algorithms, does so without changing tempo. Note that the greater the amount of transposition, the lower the fidelity—although extreme amounts of pitch transposition can produce interesting special effects. Also, some audio signals transpose more elegantly than others; for example, isolated, low-frequency sounds don’t handle transposition particularly well.
- Choose File > Open, navigate to the Lesson04 folder, and open the file DeepTechHouse.wav.
- Click an effect insert’s right arrow, and choose Time and Pitch > Automatic Pitch Shifter.
For Precision, select High Precision. Under Pitch Settings, select Use appropriate default settings. These settings are almost always the optimum choice for the best audio fidelity.
- Start playback, and note the file’s pitch. Adjust the Semi-tones slider to change pitch. For example, selecting 2 transposes pitch up two semi-tones. Selecting -2 transposes pitch down two semi-tones. Note that it takes a few seconds for the transposition to occur due to the extensive calculations that are required.
- Try some extreme transpositions, like -12 or 12, and note how this affects the sound.
- Vary the Cents slider. This provides “fine-tuning” (a cent is 1/100th of a semi-tone). Despite being a smaller change, it still takes several seconds before you’ll hear the results of any edits.