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Pitch transposition: Time and Pitch Machine


pmo

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Hi guys,

Apologies if the answer to this question seems obvious, I have only begun learning music theory over the last few months after almost two decades as a drummer.

Okay so...I'm making a track/song at 95 BPM in Eb and I have an old 12-bar trumpet sample at 94(ish) BPM in Eb. If I increase the tempo of the sample by approximately 1%, how many CENTS do I need to transpose the sample by to keep it in tune?

Similarly, if I increase the sample tempo by 10%, 50%, 100%, how many cents does it need to be transposed to remain in its original key?

I understand that 100 cents is one semi-tone, and 1200 cents is an octave, however I don't really understand how this relates to the tempo %...

Any help would be very much appreciated.

Cheers :)

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Hello pmo,

 

You could set the Time and Pitch Machine's mode to "Classic", then enter various transposition values while looking at the tempo % values update.

 

But ... what are you trying to do? I can't think of an operation that requires knowing the value of the tempo variation % value when pitching a sample? :?

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A 100% increase in tempo would require a drop of 1200 cents.

50% = 700

10%= c.165

 

1% increase is 17 or 18 cents.

 

A bit severe,but you never know.

You can change tempo without altering pitch,and pitch without altering tempo.

 

It's destructive,so make sure you use a copy.

 

If the tempo doubles,the frequency also doubles.

Double the frequency is an octave higher.

A semitone higher corresponds to an increase in frequency (and therefore also tempo) of 5.946309437%. :shock:

(12th root of 2,being the rate of increase rquired to double any given number in 12 equal steps).

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Hey guys, cheers for the speedy replies :)

David - I assumed that increasing the tempo would alter the pitch of the track...right...? Therefore I would have to compensate down to match the key of the sample to the song (which is also in Eb). Though thinking about it now, this assumption is based on my experience playing records - and since most digi-DJ programs automatically compensate for pitch changes, I would guess Logic can too. I could adjust tempo in "free" mode, right? And that would preserve the original pitch...? As I said, my music theory sucks, and I have only been learning to use Logic over the last few months so please tell me if I'm wrong.

However, if I'm not - Beermoth - Cheers dude :)

I'm re-reading the manual on the Time and Pitch Machine now and will check out a few more tutorials when I get home from uni. Though if I get a reply from anyone before that, thank you very much :)

Peace

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Why don't you use Flex Time? Polyphonic or Mono Mode. The Trumpet track is

(12 bars) apparently a little shorter than the 12 bars of the song.

Just alt + drag the trumpet region right end to the beginning of bar 13.

Pitch is the same and length is now exactly 12 bars. Nondestructive operation!

 

greetings

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Why don't you use Flex Time?

 

Because he's using Logic 8.

 

However, you could try simply holding down Option as you resize the audio region (drag its lower right corner) in the Arrange area, which will perform the Time & Pitch machine "Free" mode stretch, but you don't have to think in terms of numbers, just adjust the region's length visually.

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heh...yes still on Logic 8...

Flex Time is yet another very good reason to upgrade though...

So I ended up just altering the tempo slightly, however the trumpet sample is a solo from a 1935 blues track and as a result the tempo jumps around a few BPM here and there as the guy runs out of breath. Anyway, I compensated for it by chopping the sample up into small sections and manually quantising it (which has taken me most of the night). Now it's sounding wicked :)

Thanks everyone for the help/suggestions, appreciate it

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