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Semitones to BPM conversion
Old 11th April 2003
  #1
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e-cue's Avatar
 
🎧 15 years
Semitones to BPM conversion

So my client wishes to speed the tempo of the song we are working on up 2 effin' bpm. (seriously). It's all recorded in pro tools. Anyone got a calulation that would convert BPM to semitones/cents ? Normally I'd serato or pitch n time the track, but it seems like an aweful lot of work for 2 friggin BPM (which will no doubt change several times so I'm basically roughing it) and I don't mind the track going sharp a little bit. I swear I had this written down somewhere.
Old 11th April 2003
  #2
Rab
KMR Audio
 
Rab's Avatar
 
🎧 15 years
Quote:
Originally posted by e-cue
I don't mind the track going sharp a little bit.
I wish I had clients like this!?

Why not just swipe the timeline so everything's selected, hit Pitch 'n' Time and go for a coffee? If your chap definitely likes the faster track you can always go back and do a more detailed job later...
Old 11th April 2003
  #3
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e-cue's Avatar
 
🎧 15 years
When I pitch n time, I don't like the way it sounds when I time compressor more than 4 bars at a time, esspecially with the drums. These guys are basically ******s and I'm very likely going to switch back to the none VSOed version come mix time. $20 says they won't notice. I did it by ear, and he just asked for it to be spend up 1 more BPM. grudge If I was serious about this, I'd just retrack all the midi stuff at the correct BPM, then move the vocals and live guitar around accordingly. (it's a simple track with many many instruments)
Old 11th April 2003
  #4
Gear Addict
 
mdbeh's Avatar
 
🎧 15 years
Quote:
Originally posted by e-cue
$20 says they won't notice.
You could just leave it as is and tell them you changed it.heh
Old 11th April 2003
  #5
Rab
KMR Audio
 
Rab's Avatar
 
🎧 15 years
Quote:
Originally posted by e-cue
When I pitch n time, I don't like the way it sounds when I time compressor more than 4 bars at a time, esspecially with the drums.
I'm glad you said this. I've never been sure if you can rely on the consistency of the timestretching over long sections. If you've ever used an EMU sampler you know how it uses different algorithms for different types of material which can make a huge difference to how beats hold together.

When I get into these "is the tempo right?" situations, I'll tend to "rough" stretch the whole track as the client wants, but also do another one even faster- this usually helps to get a decision quickly rather than "mmm... can we try that a little faster?". Only when we've committed to the final tempo will I go back and do it properly in small sections (being careful to explain how painful this is and how much his faffing around is costing him..!)

heh
Old 12th April 2003
  #6
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e-cue's Avatar
 
🎧 15 years
These are the type of situations I want my clients to think are impossible so they don't ask me to do them in the future.

Anyone with a conversion yet? My net searches so far have come up nill.
Old 12th April 2003
  #7
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mdbeh's Avatar
 
🎧 15 years
This might have it:
http://www.biofunk.com/biofunk1999/a...mformulas.html

There are a bunch of formulas listed; I think what you're looking for is one of them.
Old 12th April 2003
  #8
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e-cue's Avatar
 
🎧 15 years
Seen it. What I need is a fomula that says "To go from XXX Bpm to XXX Bpm, vso it XXX semitones" with a multiplier. That or a Smeitone type calc program.
Old 12th April 2003
  #9
Mindreader
 
BevvyB's Avatar
 
🎧 15 years
groan.
good luck.
Old 12th April 2003
  #10
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Steve Smith's Avatar
 
🎧 15 years
ummm, couldnt you use Setato to find the pitch change? I am not in from t of my rig, but I think you can tell it not to maintain pitch, enter the tempo change and it tells you what the pitch change was as well?

sorry if I am wrong, it does seem too easy.

Steve
Old 12th April 2003
  #11
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e-cue's Avatar
 
🎧 15 years
Serato calucates the length, but not the semitones. I'll try the "Pitch n Time" 2.0. It's turning into studio anarchy here, as it has been the last 2 months. Great idea.
Old 12th April 2003
  #12
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paterno's Avatar
 
🎧 15 years
Quote:
Originally posted by e-cue
Seen it. What I need is a fomula that says "To go from XXX Bpm to XXX Bpm, vso it XXX semitones" with a multiplier. That or a Smeitone type calc program.
There is a program called 'Music Math' that does calculations like this. I did this same kind of thing with a friend of mine once -- only we sat there and timed it out with a metronome (7 songs we did this on)! A few days later he called me up and said an assitant showed him this program that would calculate it!!

Cheers,
John
Old 12th April 2003
  #13
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drew's Avatar
 
🎧 15 years
every 10 cents is 1 bpm. 100 cents is a half step.
drew
Old 12th April 2003
  #14
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e-cue's Avatar
 
🎧 15 years
Thank you sir!
Old 12th April 2003
  #15
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Berolzheimer's Avatar
 
🎧 15 years
Quote:
every 10 cents is 1 bpm. 100 cents is a half step.
every 10 cents is 1 bpm. 100 cents is a half step.

Hmmm...
It seems to me that this can't be quite right. Pitch scales work on linear percentages of seconds, But with BPM whenever you change tempo the size of a single beat changes- the ratio of the length of a beat to the length of a minute changes. If your formula were correct, changing from 100 to 200 bpm would be a shift of 1000 cents- adding 100 bpm x 10 cents. but we know that doubling the bpm would be a shift of an octave, which is 1200 cents.

Sorry if I'm not saying this too coherently, I'm awfully tired & bit foggy. I'll check back tomorrow & see if I'm making any cents, er, sense.

-PB
Old 12th April 2003
  #17
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drew's Avatar
 
🎧 15 years
I can follow that logic but.....

take a multitrack tape machine or a HDR that can vari speed (I have a Radar) and a gtr and take it up 100 cents and you'll find that you've pitch shifted one fret or a half step. Maybe there is an exponential relationship that by the time you reach an octave it has changed?
drew
Old 12th April 2003
  #18
Gear Head
 
Skwaidu's Avatar
 
🎧 15 years
Might be off, but:

Doesn't the Digidesign Pitch shift/ Time compression- expansion plug give you a ratio? I'm not sure(not looking at protools now), But it might work like this:
-In Time comp-ex, type in the original and desired bpm's. Check the ratio.
-Then go into the pitch shifter and type in that ratio. Should show you the pitch change in cents?

Your client probably is just insecure about something... or not
Old 12th April 2003
  #19
s2n
Gear Nut
 
🎧 15 years
Quote:
Originally posted by drew
every 10 cents is 1 bpm. 100 cents is a half step.
drew
Pitch is based on a logarithmic (base 2) scale. The above formula will not be accurate for pitches above 150cents.


n = 12 * log(freq(n) / 440) / log(2), where n is the note. A=440Hz.

cent = log2(f / 127.09)*1200, where frequency f in Hz.
Old 13th April 2003
  #20
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paterno's Avatar
 
🎧 15 years
Quote:
Originally posted by drew
I can follow that logic but.....

take a multitrack tape machine or a HDR that can vari speed (I have a Radar) and a gtr and take it up 100 cents and you'll find that you've pitch shifted one fret or a half step. Maybe there is an exponential relationship that by the time you reach an octave it has changed?
drew
There definitely is an exponential relationship between half steps: it is the 12th root of 2. Yes, pitching up 100 cents is a half step, but that number does not relate to tempo in a linear fashion.

think about it: The time it takes to go 2 BPM varies depending on the tempo. Basically 2 beats will go by slower if you are increasing from 80 to 82, than if you are increasing from 110 to 112. It is 2 beats, but two beats at a lower frequency...

-John
Old 13th April 2003
  #21
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Berolzheimer's Avatar
 
🎧 15 years
Quote:
take a multitrack tape machine or a HDR that can vari speed (I have a Radar) and a gtr and take it up 100 cents and you'll find that you've pitch shifted one fret or a half step. Maybe there is an exponential relationship that by the time you reach an octave it has changed?
I think that when you're around 100 BPM this will be true, but the further you get from that number the less accurate it will be.
Old 13th April 2003
  #22
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e-cue's Avatar
 
🎧 15 years
I've given in to bouncing it down and serato'ing to several different ways. Producer: Try 2 BPM faster. Now 1 BPM slower. How bout 3 bpm faster. O-kay bring it back half a bpm. I'd like to be able to do a quick test by VSO'ing and telling my client "That's X amount BPM faster/slower, but also X amount semi-tones.cents higher/lower". The quest continues I suppose.
Old 14th April 2003
  #23
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🎧 15 years
Quote:
Originally posted by e-cue
I've given in to bouncing it down and serato'ing to several different ways. Producer: Try 2 BPM faster. Now 1 BPM slower. How bout 3 bpm faster. O-kay bring it back half a bpm. I'd like to be able to do a quick test by VSO'ing and telling my client "That's X amount BPM faster/slower, but also X amount semi-tones.cents higher/lower". The quest continues I suppose.
Hey e-cue

As I posted before, try to find this program for the mac called Music Math. It will do the calculations for you...

-John
Old 14th April 2003
  #24
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e-cue's Avatar
 
🎧 15 years
Got a link? I've been looking all over and asking about it. No one seems to have heard of it. Any help would greatly be appreciated for a future reference.
Old 14th April 2003
  #25
s2n
Gear Nut
 
🎧 15 years
Download is at the bottom of this page.
Old 14th April 2003
  #26
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🎧 15 years
Not that this will solve your problem but I have a "tempo impaired " client too and i devised this solution. Once he starts the "lets hear it a little faster" business, I lock PT to my mx80, put it in varispeed and Wallah I can vari the sample rate of playback in pt quickly. Plus it gives a percent readout.
Old 15th April 2003
  #27
Schnert
Guest
Try this page:
http://www.geocities.com/CapeCanaver...8779/chc1.html

Find the ratio between new/old tempo (i.e. going from 120bpm to 122bpm: 122/120=1.01666666) Go to that page and fill in "1" as frequency 1 and "1.01666666" as frequency 2, and it will calculate the interval in cents and semitones.
Old 15th April 2003
  #28
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paterno's Avatar
 
🎧 15 years
Quote:
Originally posted by s2n
Download is at the bottom of this page.
Thanks for posting this...

-John
Old 3rd April 2013
  #29
Here for the gear
 
🎧 5 years
Bpm to pitch

To go a halfstep up just multiply the bpm by: 1.06.
To go a halfstep down just multiply the bpm by: .94

Based on 120bpm and our starting note being C, below are the numbers for an entire octave. Also I guess there is a tiny problem with the math... An octave should be exactly double 120 = 240 but you can see its sharp just a little bit. kinda weird:

C = 120
C# = 127.2
D = 134.832
D# = 142.912
E = 151.497 (major 3rd)
F = 160.587
F# = 170.222
G = 180.436 (fifth)
G# = 191.262
A = 202.737
A# = 214.902
B = 227.796
C = 241.464 (octave)
Old 3rd April 2013 | Show parent
  #30
Village Idiot
 
Labs's Avatar
 
🎧 15 years
Quote:
Originally Posted by DrewKimoCampbell ➑️
To go a halfstep up just multiply the bpm by: 1.06.
To go a halfstep down just multiply the bpm by: .94

Based on 120bpm and our starting note being C, below are the numbers for an entire octave. Also I guess there is a tiny problem with the math... An octave should be exactly double 120 = 240 but you can see its sharp just a little bit. kinda weird:

C = 120
C# = 127.2
D = 134.832
D# = 142.912
E = 151.497 (major 3rd)
F = 160.587
F# = 170.222
G = 180.436 (fifth)
G# = 191.262
A = 202.737
A# = 214.902
B = 227.796
C = 241.464 (octave)
First post - answered a 10 year old enigma!

Gustav
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