in a sequencer when a note is played, there is a closed hi-hat sound with a synth sound
how could I fix it?
Just take off a tiny bit of amp envelope attack? This is just an interim measure without knowing exactly the cause.
Does it only happen with the sequencer or also when you play it with the keyboard? Is it in AU or IAA mode? Does it go away when you raise buffer in settings? Sorry, just poking around.
Yeah, my analog hardware monosynth easily does the same with <5ms attack. Sometimes it's welcomed, sometimes it's a little annoying. If it's a sampled sound causing the noise, then it could be a bad sample, or the app not handling the sample well.