Controls: Edit Menu >> Synth Controls >> Note
Macro: MIDInote
This selects the MIDI note number, which you can use here as a
frequency control with the sound card's built-in synthesizer.
Notes are numbered 0-127, where 69 is 440.000 Hz ("Concert
A"). The Standard Musical Note Frequencies section has
a list of key names, MIDI note numbers, and frequencies
that covers the standard piano keyboard range.
You can compute the frequency of any MIDI note N from
Freq = 440 * 2^((N - 69) / 12).
See also Synthesizer Control Dialog.