crossover

try a behringer. Not a lot of dough, but good quality. Not The BEST, but hey, we're on a budget here, right? They work pretty well as far as I've heard. I've played with them a bit, but haven't gigged with one yet.

 

Bear in mind that with an active crossover, you'll need 2 amps, one to amplify the lows and one to amplify the highs. Have a look at the FAQ and read up on "Bi-Amping".

Personally I don't thins you need to worry, not with those speakers. When you mix big speakers (your 15) with small speakers (the 10's, there's a certain amount of natural frequency filtering going on and if you recognise it, you can use it to your advantage.

For example. Plug into the 4x10 on it's own. Adjust your EQ until you think it sounds nice.

Now without changing any settings, plug in the 15 What happens? Appart from being louder, you've suddenly got way too much bottom end. And the way to get it back to that nice sound you like is to cut some lows from the EQ. This is a good thing because it means the 10's are now being fed less bottom end than before, and are therefore less likely to distort.

This only works up to a certain volume. That's obvious but I thought I'd mention it before one of you jumps on me.