Hi, interesting conundrum here...
I wish to record a vocal at one (lower) pitch and play it back at another (higher) pitch with a predefined tempo (120bpm) in order to get that oldschool pitched rave vocal effect (i.e. the song is at 120bpm so I want to pitch the vocals up to match it).
So Melodyne etc is out the window because that's just pitch shifting, and using some other formant based process gives different results (unless I'm wrong?). I simply want the sped up effect you'd get by mapping it and playing it across a sampler.
So my question is, what is the formula for calculating pitch to tempo? Let's say I wanted the target vocal in Fm at 120bpm, and I recorded it 5 semitones down in Cm... what tempo should I record the original vocal at so it will align at 120bpm?
I'm not so good at maths so need help thinking about this. And I'm looking for a formula not the answer, as I don't know what will work best yet.
Hope that's clear...! Thanks
You are here
Pitch to tempo mathematics...
5 posts
• Page 1 of 1

siderealxxx  Regular
 Posts: 405
 Joined: Sat Jan 24, 2009 1:00 am
 Location: Cambridgeshire
Excess makes the heart grow fonder
Re: Pitch to tempo mathematics...
You've almost answered your own question as you've already made a note frequency chart.
So read off the frequency of an original note, divide that into the frequency of the slowed down (or sped up note if going the other way), then multiply the original tempo by that value.
For speeding up, lets say A4 at 440Hz and 120 BPM. Five semitones up is D5 at 587.33Hz. 587.33/440 = 1.335 (to 3 decimal places) . So 120 x 1.335 = 160.2BPM
And for slowing down 5 semitones down it would be the other way, so 587.33/440 = 0.749. So 120 x 0.749 = 89.88BPM.
But you really need top use more decimal places if possible to get a more accurate and consistent shift.
So read off the frequency of an original note, divide that into the frequency of the slowed down (or sped up note if going the other way), then multiply the original tempo by that value.
For speeding up, lets say A4 at 440Hz and 120 BPM. Five semitones up is D5 at 587.33Hz. 587.33/440 = 1.335 (to 3 decimal places) . So 120 x 1.335 = 160.2BPM
And for slowing down 5 semitones down it would be the other way, so 587.33/440 = 0.749. So 120 x 0.749 = 89.88BPM.
But you really need top use more decimal places if possible to get a more accurate and consistent shift.

Wonks  Jedi Poster
 Posts: 8626
 Joined: Thu May 29, 2003 12:00 am
 Location: Reading, UK
Correcting mistakes on the internet since 1853
Re: Pitch to tempo mathematics...
Wonks wrote:You've almost answered your own question as you've already made a note frequency chart.
So read off the frequency of an original note, divide that into the frequency of the slowed down (or sped up note if going the other way), then multiply the original tempo by that value.
For speeding up, lets say A4 at 440Hz and 120 BPM. Five semitones up is D5 at 587.33Hz. 587.33/440 = 1.335 (to 3 decimal places) . So 120 x 1.335 = 160.2BPM
And for slowing down 5 semitones down it would be the other way, so 587.33/440 = 0.749. So 120 x 0.749 = 89.88BPM.
But you really need top use more decimal places if possible to get a more accurate and consistent shift.
Ok thanks! You make it sound so simple, don't think I would have ever worked that out
Will put it to the test! Cheers

siderealxxx  Regular
 Posts: 405
 Joined: Sat Jan 24, 2009 1:00 am
 Location: Cambridgeshire
Excess makes the heart grow fonder
Re: Pitch to tempo mathematics...
Reaper or Melodyne will time stretch/contract without pitch change or change pitch without time stretching a track so you could make a best guess and tweak it later.
But a 5th down would be 2/3 the frequency of the target key so record at 80BPM and you should be very close (then autotune maybe)?
I won't work out the formula as Wonks has done that.
edit : just realised you said 5 semitones not a fifth.......
But a 5th down would be 2/3 the frequency of the target key so record at 80BPM and you should be very close (then autotune maybe)?
I won't work out the formula as Wonks has done that.
edit : just realised you said 5 semitones not a fifth.......

Sam Spoons  Jedi Poster
 Posts: 9544
 Joined: Thu Jan 23, 2003 1:00 am
 Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........
Re: Pitch to tempo mathematics...
I’m crap at math so being a logic user I would just use Logic’s sampler plus pitchbend for fine tuning. Unless I’m missing the point, which is very possible.

ManFromGlass  Frequent Poster (Level2)
 Posts: 2032
 Joined: Sun Jul 24, 2011 12:00 am
 Location: In the woods in Canada
Who is online
Users browsing this forum: No registered users