Reference

Pitch

The pitch section consists of a slider, a text field and 50 small buttons.

Pitch

This text field simply reflects the current pitch value. You can type numbers directly in here. The values represent semitones (12 semitones is an octave).

Pitch Slider

The slider controls the speed of the virtual tape, over a range of two octaves i.e. you can go from half-speed up to double-speed.
If you hold the option key while dragging the slider, it will only move to whole number values.
If you hold the command key and click on the slider, it will return to zero.

'Piano Keys'

The many small buttons above and below the pitch slider are layed out in a black and white pattern like a piano keyboard. These buttons let you set the pitch slider directly to whole semitone values.
The upper set of buttons just change the pitch. The lower set of buttons also reverses the tape direction. NB This means that if the tape is already reversed, they will change the direction to forwards.