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Change pitch+tempo by BPM, not percentages?


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#1 Overkillian

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Posted 21 October 2017 - 05:59 PM

Is there any way to change both pitch AND tempo in terms of BPM in any program??

I have searched all over, and tried checking in both Cubase and Audacity, but they measure speed change (tempo+pitch) only in terms of percentages. Or "File Rate".

I have an old audio track in 118 BPM that I would like to change down to 96 BPM with the pitch tune applied/following proportionally hereby. I find no way to measure or calculate this change by other parameters from what I see.



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#2 Chris Cosgrove

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Posted 21 October 2017 - 06:36 PM

I may be wrong because I do not know what 'BPM' stands for but since 96 is 81.36% of 118, wouldn't this be a reduction of 18.64% ?

 

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I am going to be away until about the 22nd October. Time on-line will be reduced and my internet access may be limited. PMs may not be replied to as quickly as normal !


#3 Overkillian

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Posted 21 October 2017 - 07:51 PM

BPM stands for beats per minute, a widespread measure of musical tempo.

That was one of my early thoughts, and it seemed logical, but apparantly no. 1st of all, I can only use percentages with mere timestretching (where pitch is unchanged) and when I tried to just check with that difference it didn't match with the 96 beats.

And 3rdly, I don't fully reach the precise BPM count through percentages, because many of those differences have a plethora of decimals.


Edited by Overkillian, 21 October 2017 - 07:51 PM.


#4 Platypus

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Posted 22 October 2017 - 01:35 AM

What Chris has said is correct. If you change speed -18.644%, BPM of 118 will become 96BPM, and pitch will drop in the same proportion (3.57 semitones). There's nothing else to it.

I can't say if there's any software that allows the operation directly, but in Audacity you can easily enter the BPM in the Change Tempo dialog, cut the resultant percentage change and paste into the Change Speed dialog.
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#5 Overkillian

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Posted 28 October 2017 - 06:29 PM

Hm, I wonder why I don't receive any notifications per email despite subscription. So excuse the thread bump.

No, it actually isn't. I did try -18,644% percent and the tempo was quite beside it, I also checked and found out via a timestretch calculator that it has to be changed 122.917% which gave the real result.

Maybe because they represent a count within a minute they are more than just a couple of numbers. It's also a different % when changing between a different couple of tempos, even if there is the count between the BPM numbers is the same (like 118 vs. 96 or 96 vs. 74).



#6 Platypus

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Posted 29 October 2017 - 08:45 PM

I did try -18,644% percent and the tempo was quite beside it


I don't understand what you mean by "the tempo was quite beside it".

It looks like you're not noticing the difference between the two different ways of expressing the same thing. The same tempo and timestretch variation yield a different proportional amount.

Different audio applications use these different names for the same process. Of the two I mostly use, Audacity calls it tempo, Cool Edit Pro calls it timestretch. I just need to use the right method with the right percentage figure in each application.

Consider the example of 1 minute at 100BPM, being reduced to 90BPM. That's a tempo reduction of 10% (i.e -10.000%), after which 90 beats then occur in the 1 minute. The remaining 10 beats after the 1 minute point are each now longer in duration, like all the new beats, so take longer than the 6 seconds (10%) they used to take before. So the total time is stretched more than 10%, it will increase 10/9, so 11.111%

10% tempo (BPM) reduction doesn't equate to 10% timestretch (total 110%).

That's why in your example, a tempo reduction of 18.644% results in a timestretch of 122.917%

To do the calculation, one is the inverse of the other, so as per Chris's original observation, 96BPM is 81.36% of 118BPM, inverse is 100/81.36 = 1.229 = 122.9% (neglecting rounding errors), your timestretch result. They're the same thing.

Equally, changing different BPMs by the same number of BPM has to result in different percentages. 100BPM made 10 BPM slower is a 10% reduction in tempo, 50BPM made 10BPM slower is a 20% tempo reduction. There's no way around that, and it will affect pitch proportionally if you do a speed change. So if the BPM change you desire doesn't match the resultant pitch change, you need to do it in two separate steps.

Edit: Incidentally, as to why the different, potentially confusing, terminology for the same process? I suspect it depends on whether those functions of the audio application are developed from the point of view of beats (dance, DJ, MIDI...) or elapsed time (soundtracks, radio/videos...)

Edited by Platypus, 29 October 2017 - 09:09 PM.

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#7 mightywiz

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Posted 09 November 2017 - 05:56 PM

you know there is karaoke software out there that can change tempo without any effect on the pitch and change pitch without effecting tempo.

 

also being a karaoke host I use software like this all the time.



#8 Platypus

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Posted 09 November 2017 - 10:41 PM

Overlillian specifically asked to change speed (pitch and tempo simultaneously), but referencing BPM. Can you say whether any of the karaoke software you use has that exact function, presumably without needing to use a karaoke format? Overkillian didn't say, but we're assuming they're using a .WAV file.


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#9 mightywiz

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Posted 10 November 2017 - 12:30 PM

almost all karaoke hosting software will allow you to play an audio file and adjust tempo or pitch without effecting the other, and yes you can adjust them individually or both at the same time.

karma karaoke

compuhost karaoke

pcdj w the karaoke addon or pcdj-i

siglos karaoke

microstudio's hoster

powerkaraoke.com:  has in independent program that allows you to save the modified song called "Karaoke Sound Tools 2"



#10 Overkillian

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Posted 17 November 2017 - 04:42 PM

Sorry (again) for the bump, I don't get email notifications despite subscription and correct setting:

Just for eventual clarity, I only used .WAV in all this. And I found out I could use a Cubase function, named "Resample" (under right click - process).



#11 Overkillian

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Posted 17 November 2017 - 05:05 PM

 

I did try -18,644% percent and the tempo was quite beside it


I don't understand what you mean by "the tempo was quite beside it".

It looks like you're not noticing the difference between the two different ways of expressing the same thing. The same tempo and timestretch variation yield a different proportional amount.

Different audio applications use these different names for the same process. Of the two I mostly use, Audacity calls it tempo, Cool Edit Pro calls it timestretch. I just need to use the right method with the right percentage figure in each application.

Consider the example of 1 minute at 100BPM, being reduced to 90BPM. That's a tempo reduction of 10% (i.e -10.000%), after which 90 beats then occur in the 1 minute. The remaining 10 beats after the 1 minute point are each now longer in duration, like all the new beats, so take longer than the 6 seconds (10%) they used to take before. So the total time is stretched more than 10%, it will increase 10/9, so 11.111%

10% tempo (BPM) reduction doesn't equate to 10% timestretch (total 110%).

That's why in your example, a tempo reduction of 18.644% results in a timestretch of 122.917%

To do the calculation, one is the inverse of the other, so as per Chris's original observation, 96BPM is 81.36% of 118BPM, inverse is 100/81.36 = 1.229 = 122.9% (neglecting rounding errors), your timestretch result. They're the same thing.

Equally, changing different BPMs by the same number of BPM has to result in different percentages. 100BPM made 10 BPM slower is a 10% reduction in tempo, 50BPM made 10BPM slower is a 20% tempo reduction. There's no way around that, and it will affect pitch proportionally if you do a speed change. So if the BPM change you desire doesn't match the resultant pitch change, you need to do it in two separate steps.

Edit: Incidentally, as to why the different, potentially confusing, terminology for the same process? I suspect it depends on whether those functions of the audio application are developed from the point of view of beats (dance, DJ, MIDI...) or elapsed time (soundtracks, radio/videos...)

 

 

I meant the tempo was way off. It doesn't seem to be measured that way at all, which I found out from the tempo/pitch calculators I suddenly came across.

I used that first percentage to begin with. I don't know how it mathematically hangs together, but I found out (also) that the difference in percent between two given BPM rates isn't the same, even if the difference between two BPM numbers is the same (as I examplified).

Yes they're called by several different words, the semantics happen to overlap a bit - i.e. in some DJ jargon, tempo is used as expression for both tempo/pitch combined, but usually it just means the music speed itself.

 

And okay you're right - maybe the length between tracks plays into this, but I was looking. I based my observation from trying to reduce tempo with -18.644%. The application was measuring in beats. But thanks for clearing that up.






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