OP-1/OP-Z mode vs PO-33 mode

The OP-1/OP-Z sampling engine and PO-33 (and variants) sampler are obviously rather different beasts. The OP-1/OP-Z is able to import new sample packs over USB, while new samples for the PO-33 can only be added by sampling them live via the line-in.

As such, sample packs for the PO-33 have no concept of one-shots, loops or chromatic multisampling. The dynamic downsampling feature, however, still applies. The chord generation feature too can be quite useful on the PO-33.

The application will always downsample to the nearest semi-tone (e.g 12 per octave), so that it is possible to restore the original pitch of the samples by jumping semitones, rather than some other, more difficult to achieve measure.

Using the application in PO-33 mode

The amount of available sample space per pack is fixed on the OP-1/OP-Z (12 seconds at 44kHz). However available free sample space (40 seconds in total, ~23 seconds with factory samples loaded) on the PO-33 may vary depending on what other samples are already present on your device. Therefore, the application requires you to specify the sample pack length in seconds in PO-33 mode.

To activate PO-33 mode for a collection of samples, append a space, followed by 'PO-33.', followed by the amount of seconds to the name of the directory that contains your samples. For example 'Drumkit PO-33.7' will launch the application in PO-33 mode and will squeeze all samples in that folder into 7 seconds.

For your convenience PO-33 sample packs will have their samples separated by 200ms seconds of silence.

Please note that, because the PO-33 pitch correction does not go beyond one octave, the dynamic downsampling feature will issue a warning if it is forced to downsample more than one octave (since the pitch difference can no longer be compensated for on the PO-33 by changing the sample's pitch playback). It may still be possible to achieve the correct pitch by using FX 8 ("ocd").

A PO-33 sample pack is preceded by a 200ms pulse which is tuned to 440Hz (A) at its corrected pitch. This pulse serves three purposes;

• It will cause the PO-33 to start sampling without the first sample needing to reach a threshold (potentially cutting off the first sample).
• It serves as an audio cue for the user
  
• Most importantly, it serves a a calibration tone for easy calibration of the pitch to the original samples' pitch.

To restore sped-up samples to their original pitch, it is highly recommended to have a reference 440Hz tone handy. Since the PO-33 does not provide a precise readout of the pitch correction on its display, calibrating the 200ms pulse against a 440Hz reference tone is an easy way to ensure all samples will play at their originally intended pitch. To change the pitch of your samples, press the FX button until the display says 'ton', then change control knob A to match the pitch

Alternatively, you can try calibrating by ear; make note of the semitone value that the application outputs for each sample, by carefully changing control knob A, you can jump semitones, where fully turned left corresponds with a semitone value of -12. When dealing with a sample (for example a drum loop) where pitch is harder to establish, you may wish to create a pattern that plays the full drumloop at the original BPM in a loop. Adjust the sample's pitch until the loop is playing back seamlessly.

Using the application in OP-1/OP-Z mode

The application operates in OP-1/OP-Z mode by default and no special modifications need to be made to the directory name.