When does BPM increase of a single beat become a sustained note?

lukedlb · June 2022

By increasing the beat of a single note, at what BPM does it perceivably (to the human ear) become a single note?

mrkb · June 2022

Guess it depend on the age of the recipient- I can hear to about 12k, so that’s a high BPM. Though the brain might fill in gaps at frequencies below that like it does with TV images.

Roland · June 2022

It depends .... doesn’t it always. If you run a slap back echo at 120ms, and slowly reduce the delay time, there’s a point between 20ms and 70ms where the notes will merge. The actual point depends on not just your ears, but how your brain has learned to process what your ears hear. As the notes merge the sound will change due to phase differences. Since phasing is related to frequency the effect will depend on the frequency content of the note.

Let’s take it a step further. My hearing aids have a latency of 7ms. When I first wore them each time I put a china plate on the table it sounded cracked. This was how my brain interpreted the 7ms delay. After two weeks my brain adjusted to what it was hearing.

flying_pie · June 2022

It won't just be down to BPM. The chosen noise/timbre will be a factor.

I'd imagine a short, high pitched accent will take a much higher rate, whereas white noise, or a rumbling very low bass note lasting a full measure could become a single note at a lower bpm

steamabacus · June 2022

Expanding the subject somewhat, Adam Neely has made some fascinating videos on the relationship between pitch and rhythm and how we percieve them.

PolarityMan · June 2022

Roland said:

Let’s take it a step further. My hearing aids have a latency of 7ms. When I first wore them each time I put a china plate on the table it sounded cracked. This was how my brain interpreted the 7ms delay. After two weeks my brain adjusted to what it was hearing.

Oh man that must be sooo annyoing.

lukedlb · June 2022

Thanks for your replies everyone. So there is a perceived moment where a single repeated note is so fast that it is perceived as a single sustained note.

Sporky · June 2022

I would guess that it's probably a bit over 1200bpm, as that'd be 20hz.

digitalkettle · June 2022

I'm sure I saw a vid about this ages ago where someone used a percussive sample and changed the frequency of repetition to produce a range of pitches.