By Gregory Cheng, RPT
Rather than trying to count beats per second, use a metronome to find the tempo of the beats.
Metronomes are used for establishing the tempo of a piece, typically while practicing. Metronome marking in music is counted as beats per minute (bpm). Just as a musician would subdivide the beat to determine the speed of 8th or 16th notes, we can also subdivide to find beats per second. By subdividing each metronome tick by 16th notes, we can establish four beats per tick.
Use the common mnemonic devices to help you internalize the accuracy of a beat subdivision:
Each beat would be counted in a 4/4 measure as: 1...2...3...4… (these are quarter notes)
To subdivide into 8th notes: 1-and 2-and 3-and 4-and.
To subdivide into 16th notes: 1 E and A, 2 E and A, 3 E and A, 4 E and A.
To set the F3 - A3 beat rate at 7 beats per second to a metronome marking, set the metronome to 105 bpm and listen for the 16th note pattern.
You could also set the metronome marking to 140 bpm and count 8th note triplets, or three beats per tick.
To convert beats per second to a metronome marking at 4 beats per tick, multiply the desired beats per second by 60 then divide by 4.
(BPS x 60)/4 = metronome marking you want to use while counting the 16th note.
(BPS x 60)/2 = metronome marking you want to use while counting the 8th note.
To make things easier, I have included a table of metronome markings: