How to transpose Adventure Kid's Single Cycle waveforms

It took a while to find out, how a .wav file with a single-cycle waveform in it could be transposed. For example, if the original .wav file is in D2, and I'd like to use it in a sampler that assumes C2 as a base key for its sound data, how could I just stretch it from, say, 654 to 734 samples? There are lots of tools which can stretch a sample but keep the pitch or change the pitch but keep the same sample length, and both are not helpful.

For my Sonicware Lofi 12-XT groovebox sampler I had the need to convert all the Adventure Kid's waveforms (AKWF) from D2 to the key of C2 and to 24kHz sampling rate–the highest rate my sampler can handle.

If you want to transpose more folders of samples, it is beneficial to create the same but empty folder hierarchy somewhere else for the export of the transposed files.

The solution I found is based on Audacity, and it goes like this:

1. Open a new Session in Audacity

Just open an empty session.

2. Import all single-cycle waveform sample files

Go to menu File -> Import -> Audio and select all the files which you'd like to convert. All choosen waveforms must have the same length in this run. For AKWF this is the case, all samples are in the key of D and have exactly the same length. I took the samples for the AKAI-MPC as a base.

3. Select all

Press <CTRL>+a to select all loaded samples. Don't forget this!

4. Transpose the samples

Go to menu Effect -> Change Speed and Pitch... and at the very right of "New Length:" right of the numbers you can change the unit from seconds to samples.

Now you can see the current sample length and dependent on the Speed Multiplier you choose you can see the resulting lenght in samples below.

Press apply to transpose the samples

5. Export the transposed samples

Go to File -> Export -> Audio and set you target sample rate. Also choose "Multiple Files" and choose to Name Files: Using Label/Track Name. Adapt these settings to your samplers needs.

Transposing to the samplers generic key has the advantage that you don't need to tune each sample individually in your sampler. They simply fit on the first load.

6. Remove the tracks

Now clean it all up and remove the already saved samples from your work area with menu Tracks -> Remove Tracks.

Start over with the next folder of samples, if needed.

Calculations

If you want to transpose single-cycle waveforms from one sample length to another you first need to have a table of all keys which are commonly in use.

The following table shows sample counts for the 2nd octave, means: four times the values of 4th octave. The lower the frequency the more precise the sample is:

If you want to calculate yourself, the formula is like this:

sample count = sample rate / tone frequency

Download my results here

Here are the results of my one hour converting session, ready to be used on my Sonicware Lofi-12 XT sampler:

Links