It is possible to import PCM wave files and convert to 1-bit DPCM samples. The format of the samples must be raw PCM, no compressed formats are supported. Sample rate, sample size and channel count doesn't matter, the file will be resampled according to the quality setting.

Choose import in the DPCM instruments dialog, select a file and a new dialog will come up where you choose quality and volume:

• Quality
  Sets the sample rate of the converted file, this is the same as the pitch setting in the instrument editor. Use the same to play the sample at original pitch. Quality of 15 will give best result but also shortest sample time.
  
  
• Gain
  Sets the conversion volume level. Range: -12dB to +12dB.

Maximum supported size of one DPCM sample is 4 kB, at quality 15 (33 kHz) it's a little less than one second and lowest quality (4 kHz) about eight seconds.