Hi all
Am 01.10.2018 um 09:21 schrieb Frank Sheeran:
current = previous * multiplier + delta
Am 01.10.2018 um 09:21 schrieb Frank Sheeran:
> current = previous * multiplier + delta
Im a using this multiplication with offset to sequentially generate and
detune the frequencies for music channels:
Playing with Commodore VIC20 and C-64 I found the relation of 185/196 as
a good approximation for the relative frequency distance of two notes.
For this kind of tuning, I am using a cyclic iteration to generate the
frequency values for organ like instruments in order to prepare the
values for all channels in sequence leading to a logarithmic scaling (12
notes per ratio 2). Is is very close to the temperted tuning:
http://www.96khz.org/oldpages/musicfrequencygeneration.htm
Now, regarding the topic, adding an offset during multiplication like
mentioned here, helps to detune this logarithmic scaling that way, that
frequencies at the lower end can be lower than math "says", while higher
frequencies can be slightly higher. This is necessary when coming to
piano tuning to fullfill the spreading issue often observed with real
piano frequency timmings.
Also this tuning can help to handle the psychoacoustic non linearity
issue decribed here:
https://de.wikipedia.org/wiki/Mel
Around 2005, I implemented such a detailled adaptive logarithmic scaled
curve to create measurement systems to drive and test industrial hearing
systems / cochlear implants for a customer.
After having dealed with this topics, i started to try around to use
that in music apps by dublicating MIDI channels and using individual
harmonics with detuned frequencies rather than creating harmonics by non
linear circuits wich automatically created harmonics hard linked to the
base frequency.
You may tryout yourself about the difference.
Jürgen
www.96khz.org
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