When making tonal multi-sampled instruments (not drumkits), I do it wrong. Why? Because it's less laborous that way.
If I have samples for each octave, like C2, C3, C4, C5, C6, C7 - instead of keeping them all in the same base note in the Sample menu, I Transpose them all to the same median pitch in the Samples tab, ie they all play at the same pitch on the same note.
It leads to this (transposition - sample playback rate at C3):
C2 +3 octaves - 352740 Hz
C3 +2 octave - 176370 Hz
C4 +1 octaves - 88200 Hz
C5 +0 (no change) - 44100 Hz
C6 -1 octaves - 22050 Hz
C7 -2 octaves - 11025 Hz
This way I don't need to re-type all the notes one-by-one to transpose the octaves in the Sample Map note column (which would have to be done if every sample was on a different octave), nor use the "Edit Sample Map" tool which is a bit unintuitive to use.
The problem: the playback sample rate for the C2 is pretty insane. Some programs, like the BASS MO3 encoder may get, how should I put it, upset by it. Fortunately OpenMPT doesn't limit how high a value you can enter in the sample rate field. Is there any better way to do this? (By "better" I mean "requiring less work, yet not causing extreme values"

)
Feature suggestion:
- allow click-drag or shift-arrowkey-selecting a longer range of notes in the Instruments | Sample Map column
-> Right click menu command to "Map selected to Sample ##"
-> Right click menu command to "Transpose selected up/down 1 octave / semitone"
- Maybe a way to edit the sample map columns in a separate, taller window so you could see a longer range... hmm...
(if this gets +1'ed, I can post it to the Feature Requests forum)