FX units not working on all samplers

[Cyborgscode]

Name : mixxx
Version : 2.5.4
Release : 1.fc42
Architecture: x86_64
Install Date: Do 25 Dez 2025 10:01:07 CET

As illustrated in this screenshot:

The sampler on the right side do not work with at least Units 3 and 4, but the one on the left side does work.

the samplers on the right will start working after an event i did not figured out yet.

telling the master channel to use FX3, does work as expected, it's just the sample units on the right.

A few releases back, they all worked flawless.

[ronso0]

That is strange. So you press play on sampler 5 (right side, top left) and there is no echo or reverb?
Does it make a difference if you enable 16 samplers?

Please share your mixxx.cfg, it's in your settings directory.

[ronso0]

@Cyborgscode I moved the report from the manual repo to the Mixxx repo.

[Cyborgscode]

It does not make a difference of the Sampler 5-8 if 16 samplers are selected. I moved a sample into sampler #16 4th row, bottom, right, and it also did not work. 1-4 working fine. But as 5-8 also worked a few releases back and in between releases, 5-8 could be brought to work with the fx units after hundreds of random actions, i image from 40 years of coding experience, i will be a trivial bug like "not updating a loop/array from 1...4 to 1...8 or 1...16, if 8 / 16 samples are selected."

[Cyborgscode]

mixxx.cfg.zip

[ronso0]

Okay, the config is correct, like the GUI state matches the engine fx assignment for the samplers

[EffectRack1_EffectUnit3]
group_[Microphone]_enable 1
group_[Sampler4]_enable 1
group_[Sampler5]_enable 1
group_[Sampler7]_enable 1
group_[Sampler8]_enable 1

[EffectRack1_EffectUnit4]
group_[Sampler2]_enable 1
group_[Sampler6]_enable 1

I'll try to reproduce. But I'm not aware of any recent changes in the effect engine that may cause this.
Do you remember with which Mixxx version it worked?

[Cyborgscode]

on 1.7.2025 it worked for sure, as we had a semi-public event. I noticed the misfunction a few weeks ago.

I checked my install history and found version 2.5.0 was installed at that time it was fully working. But unfortunately, i can't tell you with which exact version the issue started.

[Cyborgscode]

ohh.. i think i know what happend... the FC41 releases 2.5.0 -> 2.5.3 have been compiled and supplied by the RPM-Fusion team and with FC42 the package was introduced in the main Fedora repos.

10:1 the new build src did do something wrong.

[Cyborgscode]

https://bugzilla.redhat.com/show_bug.cgi?id=2425903

[rathann]

Fedora package maintainer here. Can you check if the latest 2.5.3 from RPM Fusion works for you? The only changes between the builds in RPM Fusion and in Fedora are requiring faad2-libs instead of faad2 and dropping -DCMAKE_DISABLE_PRECOMPILE_HEADERS=ON from cmake options. All tests pass in both cases.