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IK Hammond B3-X will not load correctly after MG patch change

Hi together,

I have a strange issue with IK Hammond B3-X on iOS (iPad 2019):
When I change a MG patch (with fingertips) where B3-X is used as AUV3 instrument, the loading of B3-X fails every second time. The lower half of MG (where the UI of the AUV3 is shown) only gets white and there is no sound. If i reload the MG patch (it does not matter if it is just the same MG patch or another one with B3-X as instrument) it works and B3-X UI is shown again. It is reproducible that this happens on every second MG patch change. With Neo Soul Keys there is no problem, so this may be B3-X related. But I have no idea what to tell IK Multimedia or how to test it on my own. Can you imagine what could happen here?
Or do you know any “generic” AUV3 host where I can test a similar behavior to find out if it is a B3-X or an MG issue?

Thank you :blush:

It is most likely a iOS system issue: when every N-th time a AUv3 plugin doesn’t work, the number N is dependent on the plugin, some plugin crash at the 10th reload, some at the 20th.
But it is vague, and currently things are shifting a bit in iOS. The last time we tested the “plugin stuck at N-th reload” problem, the problem was the same in other AUv3 hosts. Then iOS 13 came and the number of reloads before getting stuck increased considerably.
When it is this problem, CPU (right top of screen) goes 100% when the plugin is loaded. A reload of the patch will then be ok again.

Hi Paul,

thank you for the analysis, but I am not sure if this is only iOS related. The Hammond plug-in only crashes when a patch with Hammond plug-in was loaded before. And it is always N = 2.
But: When Neo Soul Keys or any other plug-in was loaded before and I just switch between patches with Neo Soul <-> Hammond, everything is OK and the Hammond didn’t crash one single time…

I will send you a link to a dropbox video by mail because I am not sure if I am allowed to post links here.

Being a software developer by myself (but not for iOS) I thought of a possible workaround: Couldn’t you just check CPU usage after changing a patch and if this seems to be suspicious just reload the patch in the background?

You said “a reload of the patch will then be ok again”. But this is not so easy in live situations and especially not so easy with my Fractal AX8 because PC messages there are only generated with a patch change. So hitting my foot controllers button again will not work.

Thank you for your help!

We ofcourse thought about detecting the suspicious CPU load, but it is highly dangerous when the device is loaded, and would trigger a oscillation ( external factor might cause the CPU spike, then the reload would make things worse ).
You can drop any link here.
I’m wasn’t implying that everything is ok for live situations then, was just describing the fault pattern.

If I am allowed to drop links, here is where you can see the behavior:

But if this cannot be solved so easily, any recommendations what I could try to set up an easy, reliable system that just switches sounds from different plugins by a PC message from my Fractal AX8 unit?
Didn’t try Audiobus or AUM, does this make sense? Or will these apps not work anymore with MG since IAA is not supported anymore in the beta?

Also looking for an app that could transform one incoming PC message to two PC messages (one for changing to a Neo Soul Keys patch which always works, the second for changing to a B3-X patch). Weird, but maybe works. But I have no idea which app could do this…

And apart from the problem with B3-X, which unfortunately makes it unusable for me live, I love your app :blush:

Thank you