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IDProjectCategoryView StatusLast Update
0001770OpenMPTlibopenmptpublic2024-04-02 21:53
ReporterYalek0391 Assigned To 
Status closedResolutionno change required 
Platformx64OSWindowsOS Version11
Summary0001770: Specifying custom Zxx macro configurations to do High pass filter (f0f002xx) cuts at random filter frequencies

This occurs in the most recent versions of openMPT, whereas I set filter mode for high pass filter does not produce a smooth transition say for scrolling a high pass filter (having a series of rows say for 128 total for reserving the z80-zff macro), it is not smooth like it should be. LIke, the filter jumps immediately from a standalone filter to suddenly enabling the filter at z90 or something with a very noticable change, instead of a gradual change like "set filter cutoff" does. It does it again with z96 or zb0 with an even higher range, which means I would probably have to put \xx which stinks...Unsure though if it does do any change to the result...

Granted I was doing this on an MPTM module with a couple patterns, and instruments with these filters enabled...
I am not sure if it affects all the other module formats related to IT.

I have not tested this on 1.31.06.

Steps To Reproduce

Create an OpenMPT Module (maybe IT if it is also affected).
Import samples.
make the instrument envelopes.
Modify the ZXX macro config (windows) in View->Zxx macro configuration.

Choose Fixed macro Z80-ZFF from the dropdown and enable that exact filter (high pass/f0f002xx).
See if you notice any difference with the newly customized filters vs the default z00-z80's f0f000xx.

TagsNo tags attached.
Has the bug occurred in previous versions?yes
Tested code revision (in case you know it)


Saga Musix

Saga Musix

2024-04-02 21:45

administrator   ~0005905

I believe you are confusing MIDI macro presets "Z80-ZFF controls resonance" and "Z80-ZFF controls filter mode". The latter changes the current filter mode from lowpass to highpass if the parameter is Z90 or above, while switching back from highpass to lowpass if the value is between Z80 and Z8F. There is no such thing as smooth transition between lowpass and highpass filters (this is not a z-plane filter after all ;). It is expected that this change is immediate and harsh, it's not something you would typically use in the middle of an already playing note. After switching on the highpass filter with Z90, you can then control it with Z00-Z7F commands.



2024-04-02 21:51

reporter   ~0005906

appreciate this explanation. I thought there was something to work around this issue. Thanks saga!!

Issue History

Date Modified Username Field Change
2024-04-02 21:37 Yalek0391 New Issue
2024-04-02 21:45 Saga Musix Note Added: 0005905
2024-04-02 21:50 Saga Musix Severity major => minor
2024-04-02 21:51 Yalek0391 Note Added: 0005906
2024-04-02 21:53 Saga Musix Status new => closed
2024-04-02 21:53 Saga Musix Resolution open => no change required