I've had my Katana Mkii for a few days now and have been downloading loads of patches. A few of them sound great, however many of them seem just a little too subtle for me to appreciate - but that's another topic.
Anyway, what I've found is some patches are really quiet and others kind of loud. I've gone into the editor and can't really see what is making the difference - i.e. volume, gain, eq levels are all in the same ballpark.
Takashi Iwai spent a fair bit of effort, a few years ago, trying to get the Roland/Boss kit working with ALSA. I did a lot of testing of his patches with a bunch of Roland/Boss kit to support that, including a MK1 Katana, a GT-1, a JS-8, a GT-001 and some others: [PATCH 00/41] USB audio refactoring for better implicit feedback support - Alsa-devel - mailman.alsa-project.org
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