Something really fishy - up to the point of freezing Mint

[chestnutjam]

It's a USB sound card problem. When it's activated in the sound settings, LMMS usually goes nuts and skips through all the audio, and playback, too, like a madman. Usually, switching to built-in and back to USB sound fixes the crackling, but it may very easily become unstable and start making my whole computer VERY laggy, and if I don't act quickly, it's bound to freeze at some point. That's a tad too minty. VST's break it easily, and they always break the OS when I open a new VST when the USB port is activated.

It was always okay, it only appeared recently, like a week or two ago. I haven't been making much music lately, so I can't be for sure when the illness appeared.

If this is not the right place to get help as it may be Linux related, then tell me please where to go for help! Thanks!

[musikbear]

It was always okay, it only appeared recently, like a week or two ago.

That is the keypoint!
'You' must have done something to your soundcard-setting or driver.
I write 'You', because i have experienced software that bluntly without any what so ever attempt to ask permission, simply changes deep things in order to run -This is indeed often the case with game-demos!
Does that ring a bell?
If you have some kind of changelog, you may be able to find the reason, but othervice its a real drag. since you have not made lmms changes (?) it is most likely not an lmms issue

it may be Linux related, then tell me please where to go for help

If you have made changes to you linux, then yes, and i would recommend you to post in a mint-forum,