How to: Work out BPM to BPM "Pitch Offset" (semitone change) without online calcs

[138BPM]

If you know the BPM of a drum loop sample and you want to pitch that loop up or down to make it play at the BPM rate of your song in Reaper, I have created an Excel file that works it out instantly.

Download the Excel calc here:
https://www.dropbox.com/s/944fbajlsk...0Calc.zip?dl=1



The above zip file contains both .xls and .xlsx files of the calculator. You cannot open .xlsx files with Excel older than the 2010 version, so I have included both, but the two files do the exact same thing.

The cell with the formula is protected, but you can easily just unprotect the spreadsheet to see what's in the cells, there is no password protection on the spreadsheet.

The calc uses a natural logarithm formula (yawn!) in the far right cell:

=LN(B1/A1)/0.05776227

Now if you type say "138" in the left cell and "140" in the next cell along, the far right cell will tell you the semitone increase or decrease needed, which you can then just enter into the box in Reaper's sampler that says "Pitch offset".

It all matches with this:
http://www.thewhippinpost.co.uk/tool...calculator.htm

What if that website goes down? What if you're offline?
As long as you've got Excel, that's all you need.

This is such a revelation for me personally, it means now I don't need to physically edit any loops ever again, or mess about working anything out. Just type the two BPM values in and I have the answer instantly.

Prior to this, I was altering the pitch of the sample file after putting the BPM in another calc I have got, it was a far slower way of doing it because I was having to physically change the WAV files in another audio editing program.

Now... imagine if this feature was part of Reaper HINT HINT.

[jrk]

You can just stretch the loop to fit your grid. No need to do any sums.

[Reason]

This is a cool idea, and thanks for sharing, but I'd agree with JRK in that stretching should cover this just fine.

Prior to this, I was altering the pitch of the sample file after putting the BPM in another calc I have got, it was a far slower way of doing it because I was having to physically change the WAV files in another audio editing program.

You can do this non-destructively in Reaper. Select item | F2 (or right click > Properties) and adjust the pitch there.

[138BPM]

Originally Posted by jrk

You can just stretch the loop to fit your grid. No need to do any sums.

Do you mean like this?

https://www.youtube.com/watch?v=i1w-FBgpZ3Q

That sounds like its time stretching it, which I always avoid.

Also Reaper is guessing the BPM and it might not always work.

[Reason]

The way I'd do what he does in the video is to Alt + click the right side of the loop and stretch it to the appropriate bar line. That would time stretch it though, so if you're trying to avoid that, then pitching it might work better. Although you can go to Item Settings, uncheck Preserve Pitch when changing playrate, and then Alt + Click and it'll pitch it automatically.

[138BPM]

Originally Posted by Reason

The way I'd do what he does in the video is to Alt + click the right side of the loop and stretch it to the appropriate bar line. That would time stretch it though, so if you're trying to avoid that, then pitching it might work better. Although you can go to Item Settings, uncheck Preserve Pitch when changing playrate, and then Alt + Click and it'll pitch it automatically.

This sounds good if dragging wav files directly to the tracks, but I always assign samples to notes in the sampler and they end up as midi notes on the tracks, so it would not be stretching anything.

[Reason]

Ah, gotcha. I've so far only done that with one-hits, not loops, so I can't claim any experience with that.

[jrk]

Originally Posted by 138BPM

I always assign samples to notes in the sampler and they end up as midi notes on the tracks

That's the way we used to do it. There's no advantage to it that I can see. But of course, it's whatever works for you.

[138BPM]

Originally Posted by jrk

That's the way we used to do it. There's no advantage to it that I can see. But of course, it's whatever works for you.

I assign multiple drum loops to one track (in the sequencer with many instances of ReaSamplomatic 5000) so I can easily swap them about later if necessary, it's easy to try lots of different ones and see which 2 or 3 go well together. The only snag I have found is if I drag a note in the sequencer I can suddenly have 15 loops playing at the same time and that's loud lol

[jrk]

Originally Posted by 138BPM

it's easy to try lots of different ones and see which 2 or 3 go well together.

That makes sense.

Attached a little js fx - doesn't do anything except your calculation, but with parameter modulation you could link it to ReaSamplOmatics pitch ofset.

[138BPM]

Cheers jrk, shall grab