[sdiy] Question for those with musical ears

Mike Bryant mbryant at futurehorizons.com
Thu Apr 15 02:45:59 CEST 2021

Yes I saw the Wikipedia entry, but I’ve seen other articles saying those with perfect pitch can determine a cent change.  But this would need 12000 discrete steps which does sound unlikely.

Beats don’t matter in my case – it’s actually analysing a signal input so I need to know how many bins are needed to handle a glissando such that it sounds the same on reconstruction.

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Joan Touzet
Sent: 15 April 2021 01:40
To: synth-diy at synth-diy.org
Subject: Re: [sdiy] Question for those with musical ears

Wikipedia has a decent summary:
The JND for tone is dependent on the tone's frequency content. Below 500 Hz, the JND is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the JND for sine waves is about 0.6% (about 10 cents<https://en.wikipedia.org/wiki/Cent_(music)>).[3]<https://en.wikipedia.org/wiki/Just-noticeable_difference#cite_note-3> The JND is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches.[4]<https://en.wikipedia.org/wiki/Just-noticeable_difference#cite_note-Olson-4> The JND becomes smaller if the two tones are played simultaneously<https://en.wikipedia.org/wiki/Simultaneity_(music)> as the listener is then able to discern beat frequencies<https://en.wikipedia.org/wiki/Beat_(acoustics)>. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.[4]<https://en.wikipedia.org/wiki/Just-noticeable_difference#cite_note-Olson-4>

1400 steps is only 10.5 bits of resolution, but... the issue I'd see is dealing with beats, either in a polyphonic synth (beats with other voices) or with other instruments in the same song.

On 2021-04-14 8:26 p.m., Adam Inglis (synthDIY) wrote:

On 15 Apr 2021, at 9:47 am, Mike Bryant <mbryant at futurehorizons.com><mailto:mbryant at futurehorizons.com> wrote:

Consider a continuous glissando played on an analogue synth - the frequency rises smoothly between the start and end pitches.

But on a digital synth there will always be discrete steps between successive frequencies as the frequency is gradually stepped between the start and end pitches.

Question is, what is the minimum step (in cents) needed such that the best musical ears cannot tell the frequency isn't rising smoothly as on the analogue synth, but in many discrete steps.

It may be that the rate of change can effect it so if so please assume a glissando starting at middle C rising at 1 second per semitone.

So, you're kind of talking about the auditory equivalent of a video “frame-rate”, are you?

As in, How slow can the frames per second get before you notice a ‘flicker’?



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