Unlike all the rest of the equal-tempered scale, octaves are easy, just divide by half or multiply by two (or multiples thereof). If it's thirds and fifths and all that, it gets a bit more complicated unless you are into just intonation where the ratios are actually the ratios and haven't been "t(a/e)mpered" with (by setting up logarithmic relationships inside the octave rather than across the whole range of notes.)
http://en.wikipedia.org/wiki/Mathematics_of_musical_scales http://en.wikipedia.org/wiki/List_of_meantone_intervals http://en.wikipedia.org/wiki/Just_intonation
For myself, using the just intonation ratios just works because it's simpler math. However, like Andrew I'm not sure beyond this simple advice what it is you're exactly trying to do. So hope this helps... Any actual lettered students of tuning systems feel free to kick me, I'm a mere dilettante in this world...
best! D.
J bz wrote:
Dear all,
I have five chimes. I've worked out the frequencies (using Audacity) of the 5 strongest partials of each chime. I now want to be able to work out how to change the octaves of the various partials? My original intention was to find the nearest midinote and just use those but after listening to the results I would much prefer to keep the original ratio's whilst being able to alter the 'inversions'.
Here's the list that I have already: BT1 912Hz 2434Hz 4575Hz 7175Hz 11584Hz
BT2 1081Hz 2861Hz 5339Hz 8325Hz 15209Hz
BT3 1211Hz 3196Hz 5935Hz 9199Hz 15206Hz
BT4 1347Hz 3553Hz 6569Hz 10128Hz 18139Hz
BT5 1812Hz 4699Hz 8525Hz 13264Hz 15469Hz
Is there one piece of mathematrical wizardy that can sort this in Pd?
Cheers,
Jbz
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