Originally Posted by DukeLeJeune
Adding a midrange to an existing two-way system would be a roll of the dice unless you're somewhat experienced as a speaker designer. You can of course use an off-the-shelf three-way crossover and you will end up with a three way system, but personally I'd choose a factory-designed two-way over a roll-of-the-dice three-way.
If your heart is set on having a three-way bass cab, imo best to sell what you have before you modify it and degrade its value, and use the proceeds to get what you want.
This is some damn good advice, Duke knows his stuff.
the speakers in your combo are designed to work together, if you don't like how they work it's best to just get rid of that and look for something that does work in a way that you like. I've been thinking of designing a 110/6, 210/6, and 15/6 using some cheaper ceramic drivers to make something similar to a fEARful on a budget, but that's a LONG way down the road, I still haven't figured out exactly which drivers to use, particularly the mids, the woofers are relatively easy to figure out, it's hard to pair a midrange to go with it, and crossovers are also difficult to figure out precisely, not to mention tuning, bracing, internal dimensions. I'm reading some hi-fi design books just to get me in the right direction. I'm mostly just bringing this up as a bit of an ad, but also just to say that if designing this stuff from the ground up is difficult, it'd be even harder to figure out for a pre-made box like that, where the options are even slimmer. You'd need to design a good crossover and find a good mid driver, keeping in mind that the volume displaced by the mid-chamber impacts the tuning of the cabinet, and therefore the tuning of the drivers, etc...