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  4. An Mathematical forumula for stretching a sample to a particular tempo.

  • An Mathematical forumula for stretching a sample to a particular tempo.

    S
    S

    Hi to the forum,

    I have a piece of music where I would like to use fast repetitions, but I'd like to have them play, if possible at the speed of 126 bpm.

    I am trying to work out a kind of mathematical algorithm that will help me know how much % I need to stretch a sample or compress it to get it to fit to a certain tempo.

    Does anyone have any thoughts of what kind of forumla you would use to do this?

    thanks if anyone can help me out here.

    best,

    Steve [:)]
  • Beat KaufmannB
    Beat KaufmannB

    Hi Steve

    Time Strech% = (current tempo / used tempo) x 100%

    Example: (180 BPM / 126 BPM) x 100% = 142.85%

    Hope that works [;)]

    Beat

    - Tips & Tricks while using Samples of VSL.. see at: https://www.beat-kaufmann.com/vitutorials/ - Tutorial "Mixing an Orchestra": https://www.beat-kaufmann.com/mixing-an-orchestra/
  • civilization 3C
    civilization 3C

    that isn't stated right, though. 100% of 1.4285 is 1.4285. IE: 100% = 1. 1.4285 x 1 = 1.4285.

    180/126 = 1.4285. That's a ratio of 1.4285:1; to express that as a 'percentage [per one hundred of]' you put it in the right decimal place, multiply by 100.

    (142.85:100 is expressed as '142.85 per cent')

    180 is 142.85% of 126; 126 x (142.85/100) = 180...

    so you have a loop given at 180BPM vs the target of 126BPM. owing to *per minute*, 126 takes up 142.85% the time as 180 does.
  • S
    S

    Hi Beat and Civilization,

    thanks so much for that info. I will try this out and see how I go.

    best,

    Steve[:)]
  • Beat KaufmannB
    Beat KaufmannB
    last edited
    last edited

    @civilization 3 said:

    that isn't stated right, though. 100% of 1.4285 is 1.4285. IE: 100% = 1. 1.4285 x 1 = 1.4285.

    180/126 = 1.4285. That's a ratio of 1.4285:1; to express that as a 'percentage [per one hundred of]' you put it in the right decimal place, multiply by 100.

    (142.85:100 is expressed as '142.85 per cent')

    180 is 142.85% of 126; 126 x (142.85/100) = 180...

    so you have a loop given at 180BPM vs the target of 126BPM. owing to *per minute*, 126 takes up 142.85% the time as 180 does.

    BlaBlaBla, also this forum seems to be more and more full of "Know-All".

    They are waiting until a stupid other member gives an easy answer and then they have their entrance...

    Steve just wanted to know: I have Repetitions recorded with 180 BPM but I want them to use with my 126 BPM.  Can someone give me a formula.

    He didn't order a dissertation ...

    I believe that I will take me out from this forum more and more - pure waste of time, sorry

    Dear civilization 3

    If you want to be a real help here then offer a real additional help please!!!

    Example:

    If you are working within a DAW you have a "time streching function" for sure (in connection with the audio part).

    There you can shift the ratio until you get the tempo (read then the %) or you enter the desired tempo by the Computer Keyboard.

    Here is the example for Cubase:

    Best

    Beat

    - Tips & Tricks while using Samples of VSL.. see at: https://www.beat-kaufmann.com/vitutorials/ - Tutorial "Mixing an Orchestra": https://www.beat-kaufmann.com/mixing-an-orchestra/
  • S
    S

    Hi Guys,

    So, am I correct in deducting from this that because  126 takes up 142.85% the time of 180, the stretch % for the sample will be a 142.85%  stretch in the software?

    So, because I am going from 150 bpm to a 126 bpm stretch, I will use the following steps [please correct me if I am wrong].

    1. I write the two tempos as a ratio eg 150/126

    2. I divide 150 by 126 to get 1.190476190476...[ I suppose I should round it to 1.2 but I will keep the original repeating decimal part]

    3. I then multiply by 100 to get 119.0476 or I round it to 120% and then, in this case I stretch the sample to 120% and this should give me a fast repetition with the speed of 126 bpm now.

    Am I correct here?

    many thanks,

    Steve[:)]
  • Beat KaufmannB
    Beat KaufmannB
    last edited
    last edited

    @Steve Martin said:

    Hi Guys,

    ...  Am I correct here?

    many thanks,

    Steve

    Hello Steve

    I would say yes - but wait until the other guy gives us the true calculation...

    (Sorry for that bad joke - but I couldn't resist)

    Beat

    BTW: Will it be possible to listen to the streching result? or to the whole piece... with Hybrid-Depths? [;)]

    - Tips & Tricks while using Samples of VSL.. see at: https://www.beat-kaufmann.com/vitutorials/ - Tutorial "Mixing an Orchestra": https://www.beat-kaufmann.com/mixing-an-orchestra/
  • S
    S

    Hi Beat,

    I thought I was correct - but I just wanted to make sure I was correct so thank you for letting me know that I am on the right track.

    I will do a recording in cubase of the examples and send it to you via email if you like and I'll use the Hybrid Reverb also.

    thanks again for your help with solving my problem.

    best,

    Steve[:)]
  • A
    A

     Maybe a VI Pro update could have the percentage calculator like Cubase has, that would be really useful. It would just need two parameters "Tempo from" and "Tempo to" and it could calculate the percentage required. Though, I seem to be usually working out lengths more than BPM, as things like crescendos are starting from a length (3 secs, 4 secs etc), so a comprehensive stretch calculator would be most welcome.