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[Patrick Bateman]

Originally Posted by XtremeRevolution

Those were the FR charts I wanted to see. You've confirmed my suspicions but impressed me at the same time. I would definitely say you'd need a midbass to play these well, along with a sub. A 4 way system it would appear (if you include the sub as being one). More complexity for better imaging and smoothness. I presume this is all run with active crossovers?

Now *thats* a controversial question!

Here's why -

Most people in car audio have a setup that looks like this:

• tweeter covering three and a half octaves, from 2khz to 20khz
• midbass covering four and a half octaves from 80hz to 2khz
• subwoofer covering two octaves from 20hz to 80hz

With these ultra-small midranges, I'd be looking at something like this:

• tweeter covering two octaves from five to 20khz (By using a very high xover point, we move the transition to an octave where it's difficult to detect. (Because we don't hear well at high frequencies.) Reducing the bandwidth of the tweeter also allows us to use very high efficiency options, such as ribbons. A high xover point increases power handling and reduces distortion too.
• midrange covering five octave from 160hz to 5khz (this is very important - by covering such a wide range we're hearing most of our imaging cues from one set of drivers. It's almost like a full range system. The idea is to eliminate that godawful xover transition in the midrange.)
• subwoofer covering two octaves 40hz to 160hz
• ULF subwoofer covering three octaves from 10hz to 80hz (optional)

I would say that this is a very unorthodox set of xover points. Particularly the idea of running your subs up to 160hz.

The reason that the subs are overlapped is because we have a catch-22 here. If we cross over at 160hz, we're going to need to locate our subs carefully so that the imaging doesn't go to hell. But if we want to get to 20hz, we're going to need a big woofer with lots of displacement. So it's a catch-22.

Overlapping the subs solves the "catch-22." A pair of small subs gives you the flexibility to locate the upper subs where they won't ruin your image. And the ultra-low-frequency sub raises our output from 40 to 80hz, and forms a low end that reaches to 10hz.

Note that this setup won't work at home; the ULF depends on cabin gain. At 20hz we're getting about 24dB for free, from cabin gain.