pitch calculations
hey...
i made this guitarloop in Reason (170Bpm) the notes are A,C and G
then i dropped this loop into mlr and it plays it (120bpm) at 1,43 speed..
and i think that this sounds much better then in original speed
but now if i want to add a bassline obviously i cant use A,C and G anymore..
is there a way to find out what the notes are now?
You've got the maths the wrong way around, you're slowing it down from 170 to 120 bpm which means it will be playing at 0.705882 speed. Here's a patch which should show you how to work it out. Unless my maths is useless too then it works out as being just a bit flatter than six semitones lower.
lh
oh yea..
i forgot to say...
of course.. just droping it in it would play at 0.7 but then i set it one octave higer.. so it plays at 1.4
anyway..
your patch is great, it told me exactly what i wanted to now. i know that this is not the last time iam going to use this...
so thanks a bunch
bye
coffeencigs wrote on Mon, 16 November 2009 16:58
just droping it in it would play at 0.7 but then i set it one octave higer.. so it plays at 1.4
and this assumption is what is wrong: 1.4 times faster is not
an octave higher than 0.7 times as fast.
its not an assumption..
this is what mlr does with the playback speed of your file, when you set it an octave higher..
btw
played in 0.7 its D#3, played in 1.4 its D#4
at least thats what the patch says, and it sounds right that way
The answer to the original question is easily searchable on Wikipedia. See, for instance, the article on Musical tuning. But I'll hand the answer to you on a silver platter anyway. The formula for calculating number of halfsteps (interval) from a given frequency ratio a/b is:
interval = 12*log2(a/b)To get the interval in cents just use a factor of 1200 instead of 12.
I was going to write that your ratio of 17:12 was just a bit larger than a tritone (six half-steps/augmented 4th/diminished 5th) but when I did the math I realized it was only detuned by about 3 cents (1200*log2(170/120) ~= 603), a difference most people can't hear in even highly controlled laboratory conditions.
Calculating the frequency ratio from a given interval is left as an exercise for the reader.
hehehehe ... that was bad luck that it is so close!
try it with 0.8 and 1.6 and you will be put back on track.
-110
.