If you have all your treble set up high though your tweeters will still distort. Try turning down the equalizer too; everything. Start at a baseline and tune your audio from there.
Tweeters play the high frequencies (treble) and only function properly at certain frequencies. I think the human ear has a frequency range of 20-20,000 Hz (or there abouts) and the tweeters will play from say 5,000 Hz to 22,000 Hz to cover that upper spectrum and a little bit more.
First off when you use a treble boost it is doing just that: amplifying the treble. This just means that there is more current powering the speaker, and when there is more current than the speaker can handle you start to get distortion and blown speakers.
Now just because those tweeters don't play anything below (random number) 6,000 Hz doesn't mean they won't pick up some other frequencies. You can try playing 1,000 Hz through them and still get sound, it will just sound horrible (probably distorted). If the bass is up and you turn up the volume; at some point your tweeters will think it should be playing the lower frequencies (bass) as well and try to play them and that should also make it sound horrible (distorted).
So yeah I'd say turn everything off (treble boost, bass boost, etc...), and set the EQ to a baseline. From there you can set your EQ parimeters: your treble, mids, and bass to their full potential, right up to the point where they will distort. Also at either your EQ baseline or your new settings (or try it at both) try one by one and combinations of all those frequency boosts. More often than not they cause a lot of distortion. You'll see this as you switch the boosts on and off.
That should help a great deal and if it doesn't work you may have bad tweeters wherein you can either replace them or pick up HPF (high pass frequency) filters.
Hope that will help, let me know how it goes