Every note is a key on the piano, a dot on the staff, and a frequency in the air — all the same thing. Tap a key, or slide the frequency, and watch the other two light up.
Find this note: —
Tap it on the keyboard below.
A4440.0 HzMIDI 69
On the staff
On the keyboard
selected note
As a frequency — slide between the notes
440.0 Hz
in tune with A4
As you slide, the exact frequency changes smoothly — but the keyboard and staff snap to the nearest named note. That gap between smooth sound and named notes is what tuning is all about.