Tap a note to play a sustained sine. Tap again to stop. With Clamp on, all references play in the C4–C6 range so you can hear them on a phone speaker.
440 Hz. Drop it
to 415 for baroque pitch, or nudge to
442 / 444 for orchestral.
Tuning swaps between Equal, Just (centred on
C), and Pythagorean — set this for a-cappella or early-music
sessions; leave on Equal otherwise.