Frequency Atlas

Compare two tones

Pick two frequencies. See the interval between them, then hear them one after the other or together. Start with the volume low.

Nearest note: A4, 32 cents below standard tuning

Nearest note: E5, 30 cents below standard tuning

Set tone B from tone A

Listen

25%

“One in each ear” sends tone A to the left and tone B to the right. It needs headphones. “Both together” and “One in each ear” play until you press stop.

The interval

+702.0 cents
Tone B is higher than tone A. A cent is one hundredth of the step between two neighboring piano keys.
3:2
The ratio of the two frequencies
Nearest pure interval
Perfect Fifth
Ratio 3:2. Exact.
Nearest interval on a piano
Perfect Fifth
7 semitones. This pair is 2 cents wider.
Octaves apart
Less than one
702.0 cents apart

The beat

The difference between the two tones as they are played.

216.00 Hz

The tones are far enough apart to be heard as two pitches, with no beat.

Set a beat rate

Moves tone B so that the beat falls in the middle of a range. The ranges are the ones used to describe EEG recordings, borrowed here as labels. Band edges are conventions and vary by source.

Ranges adapted from Kane et al. 2017, Clin. Neurophysiol. Pract. 2:170–185 (IFCN glossary). This table starts delta at 0.5 Hz and beta just above 13 Hz, and adds a high gamma range that research papers use.