That's a bit sad! It's usually the high frequencies which go first.
I've read about the Barb-EQ, and that's a cool idea. There are quite a few ways to tweak the identity of your amp, without necessarily tweaking the actual amp. That's where amp in a box pedals come in. They don't always change things how you might hope because so much depends on you, your guitar and your amp. But sometimes a pedal can just work with an amp and make sounds that make you happy. Again, it's why I like adding bass controls to overdrive pedals. It can make pedals which are not so useful into something perfect.