Loud hats are the bane of my existence, when recording hard rock and metal drummers especially. Bleed into the snare is usually the worst of it, but a lot of times the hats overpower the overheads as well. You can't bump the cymbals up without the hats sounding like someone tipping boxes of cutlery over your head because they're so loud.
There's a few ways to help this.
#1 is your absolute first choice: get the drummer to play the damn hi hats quieter, and the drums louder. Sounds like a no-brainer, right? You'd be surprised. This fixes 99% of the problem right there. After working with pro session players and then going back to n00b drummers who just belt everything because it's "HEAVY METAL, MAN - IT'S GOTTA BE LOUD," it's like night and day...! With a clever use of gates and EQ, you'll have a great mix in no time.
#2 - failing that, get some darker sounding hats. What may be fantastic sounding hats live could also be overly bright and loud when you're in the studio. A great example was our previous drummer. He had a SABIAN endorsement and those cymbals sounded
magnificent, including the hats, but the moment we got into the studio it was completely unworkable. We borrowed some pretty ordinary and flat sounding Zildjian hats that didn't sound anywhere near as good as our guy's SABIANS but in context, it was a dramatic improvement and sounded great in the actual recording.
#3 is micing technique. If you're getting a lot of bleed on your snare especially, make sure you have a mic with great off-axis rejection (a SM57 is a classic example) and point it so the back of it is facing the hats. This won't fix the overheads though, so if you rely on getting an overall kit sound from your overheads rather than just using them to capture the cymbals, you're back to looking at option 1 & 2 there. For what I do, I prefer to close(ish) mic every cymbal so I have a lot more control over everything in the final mix, and I get my actual drum sound from close-micing everything. It's almost a must to do it this way for faster styles of music because the bleed and crosstalk of a more open sounding kit just turns to mush.
#4 is when you run out of options, or it's nearly there and you just need to get it the entire way: Make a sample set of each drum in isolation (ie: 3 or so hits on each drum by itself, catching the entire decay, and dumping that into something like Kontakt or another sampler to make a custom sample set of your own kit), and then use Audiosnap to go through an detect each snare hit, and have that trigger a MIDI note in Kontakt of your sample set. Alternatively, use something like SONAR's Drum Replacer or Drumagog to trigger samples (yours or otherwise). I do this fairly often because it gives you a lot of flexibility and it really does get the hats out of the snare mic. I tend to blend the natural snare mic with the sample so it's not ENTIRELY isolated, but it's enough to really get the bleed down to a manageable level. This can easily sound fake, though, so approach with caution.
Other thoughts are, as mentioned, baffles. They CAN work but a lot of times the mics that are causing the problem are in a place where you can't get a baffle in front of, and honestly, it doesn't cut down serious problem hats too much. Definitely a useful thing to know, though.
Also your recording room is a big part of it. Room too small? Too much reflection? You're gonna have a Bad Time. Aside from potential comb filtering and phase cancellation issues, you're gonna get all kinds of stuff bouncing back at the kit, and the hats are usually the biggest culprit. Even if you dampen the hell out of the room, the sound has still got to go somewhere. You either need to play quieter or find a much bigger room so you're not getting hat wash bouncing around your other mics so much.
Take this from a guy who has dealt with (and usually been responsible for) every issue I mentioned above, and I have the grey hairs and mental scars to prove it! HAHA! But yeah, this stuff should point you in the direction to find out what work best for you.
