[Bug] Surge XT VST3 and Shortcircuit XT VST3 load with pitch that is too low

[linux-leo]

I think it's related to MPE and pitch bends, but when creating a new project, and adding surge xt, then reopening the project. Surge XT will be pitched 2 semitones too low.

I suspect the VST3 pitchbend value is set to 0 when it should be set to 0.5, maybe because of #1350

Investigating at the Surge XT repo I found out that FL Studio sends a pitchbend value: surge-synthesizer/surge#854 when loading vst3 plugins, maybe radium could do the same after loading the plugin?

[linux-leo]

I can confirm that instead controlling the vst3 instrument with midi messages and setting pitch bend to 0.5 fixes the issue.

[linux-leo]

The pitch bend parameter correspons to a midi cc parameter, which is exposed in radium as a parameter and saved between reloads. So I can workaround this issue by setting the parameter manually. Therefore not an important issue. Maybe surge xt and shortcircuit xt should be even setting the parameter themselves.

[kmatheussen]

That's strange. After a plugin has been loaded, it stores the effect values, and uses those values as "reset" effects. Can you load the Surge or the Shortcircuit VST plugin and press the "Reset" button in the instrument widget? Does it fix it, or is the pitch still too low?

[[It could also be a JUCE bug, but I can't upgrade JUCE very much since latest version doesn't support MINGW. I should probably fix that though, probably by using clang-cl instead of mingw to compile Radium on Windows. I could of course only upgrade JUCE on Linux, but that might create unnecessary chaos.]]

Anyway, sending a MIDI pitch signal after opening plugins is probably an okay workaround.

[kmatheussen]

I'm a little bit confused about the issue in the Surge repo though. Isn't this just a bug in Surge, that was fixed in 2019 in this pull request? https://github.com/surge-synthesizer/surge/pull/855/files

[kmatheussen]

I've dug a little bit into it, and at least the muffled sound has been fixed now (I didn't realize that libgig returned interleaved samples for stereo samples, which I partly blame on a very confusing API, so stereo samples have always been screwed up!).

I haven't dug into the wrong pitch being played except transposing the samples down 12 notes, but that doesn't solve all the problems. I'm planning to look at it more tonight.

A patch is attached if you want to fix the muffled sound at least.

radium_soundfont.patch

[kmatheussen]

(If you want to try the patch, you probably need to cherry pick 4922ab1 first to avoid conflicts)

[kmatheussen]

The two comments above was of course supposed to be posted to the soundfont/sample slice ticket #1461 and not here.

[linux-leo]

I'm a little bit confused about the issue in the Surge repo though. Isn't this just a bug in Surge, that was fixed in 2019 in this pull request? https://github.com/surge-synthesizer/surge/pull/855/files

Oh yeah, sorry for the confusion. No need to link to it. that was just what gave me the idea to send a pitchbend value of 0.5 to surge which fixed the issue.

[kmatheussen]

On Thu, Nov 27, 2025 at 10:47 AM linux-leo ***@***.***> wrote: *linux-leo* left a comment (kmatheussen/radium#1462) <#1462 (comment)> I'm a little bit confused about the issue in the Surge repo though. Isn't this just a bug in Surge, that was fixed in 2019 in this pull request? https://github.com/surge-synthesizer/surge/pull/855/files Oh yeah, sorry for the confusion. No need to link to it. that was just what gave me the idea to send a pitchbend value of 0.5 to surge which fixed the issue.

So your problem is caused by a different bug? Your version of Surge includes this fix? Message ID: ***@***.***>

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[linux-leo]

I have no idea what causes this issue and if it is a problem with radium or surge, but other daws do not experience this issue.

[kmatheussen]

On Thu, Nov 27, 2025 at 1:43 PM linux-leo ***@***.***> wrote: *linux-leo* left a comment (kmatheussen/radium#1462) <#1462 (comment)> I have no idea what causes this issue. sorry

Okay, as a workaround I'll just start sending a pitch-reset MIDI message to VST3 plugins then. It has to be an option though to ensure compatibility with old songs, but new songs should have this option enabled by default. Message ID: ***@***.***>

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