Pitch Bend range in Sampler seems to be ignored (or multiplied)

[Akitru]

I have a MIDI track (from an external source) that seems to ignore the Pitch Bend Range parameters of the Sampler.

I've stripped it down to the attached very simple project with two similar tracks:

1. Correct Bend - Plays a couple of notes with a gentle pitch bend up and back, and sounds correct.

2. Wrong Bend - Plays the same two notes with same pitch bend data, but the audible effect is as if there's a 10x multiplier on the pitch bend data.

AFAIK both these tracks use an identical Sampler instrument and settings (originally based on the 'Fingerstyle Bass' from the library).

Could someone take a look at this and see what I'm missing, i.e. why does the second track seem to respond so differently to what should be the same pitch bend data?  (And if they sound the same to you, well then it is even more of a mystery!)  (Version info correct in signature)

Pitch Bend Issue.logicx.zip

[gacki]

Different channels.

The second track plays the first note and Pitch Bend on Channel 2. If you set it back to 1 it will bend like the first one.

(What exactly is going on in the background I haven't checked yet.)

 

Edited March 31, 2023 by gacki

[gacki]

I think I got it now.

That's what your basic Pitch bend settings are:

However the sound has additional properties (that are normally hidden):

So anything coming in on a Channel higher than 1 uses the 48 half notes Pitch Bend Range.

As soon as you turn MIDI Mono Mode off or use Channel 1 only everything is fine.

[Akitru]

Thanks @gacki, that addressed it!  I don't think I would have ever figured that out!  And I didn't notice that expansion menu at the bottom of the Sampler when I was combing the two instrument instances for any differences (not that I would have stood out as a difference).

I've got to study that MIDI option... something new to me!

[Akitru]

Some further information for posterity...

Some Logic instruments (like Sampler) support MIDI Mono Mode, which allows them to process notes arriving on different channels with different pitch bend, aftertouch, modulation wheel, and controller assignment messages.  It is most useful for MPE (MIDI Polyphonic Expression) instruments (such as a MIDI guitar that can emit different notes and pitch bend information for each string).

This feature can produce surprising pitch bend (and other controller) behaviors if it is enabled for an instrument (which seems to be the default) and MIDI notes are received from a channel other than channel 1.  In this situation it may appear as if the instrument is ignoring its normal Pitch Bend Range setting; and indeed it is.  For notes received on channels other than 1 it uses an alternate range for pitch bend, by default 48 semi-tones.

MIDI messages may be recorded with non-channel 1 assignments if they were imported from an external source such as a multi-channel MIDI file (which occured in my scenario).

As noted above the solution is to either turn of MIDI Mono Mode from its well-hidden location (easiest) or edit all notes so they are on channel 1.

More info:

https://support.apple.com/guide/logicpro/quick-sampler-extended-parameters-lgcp3df3cd4a/mac

https://support.apple.com/en-us/HT203776

[gacki]

8 hours ago, Akitru said:

As noted above the solution is to either turn of MIDI Mono Mode from its well-hidden location (easiest) or edit all notes so they are on channel 1.

Or set the Track parameters accordingly:

to

[Akitru]

5 hours ago, gacki said:

Or set the Track parameters accordingly:

to

Slight mod pertinent to Logic 10.7.7:  Changing MIDI Out Channel to 1 will address the issue with notes ≠ channel 1 already in the track (which was the case with my imported MIDI track).