This reminds me, I read that someone was using the empeg front RCA's to drive their main amps and speakers, using the rear outs to drive a sub, and using the 4 way eq settings instead of a crossover. Is this a good idea or not? It strikes me as an interesting way to use the parametric eq.

This is do-able to a certain extent, but there are a bunch of "if's" and "you've also gotta"s to go with it.

When I first got the Empeg, I had some really old amplifiers without built-in crossovers. So I decided to try using the 4-way EQ to remove the bass from my front door speakers. (I wasn't trying to cross over a subwoofer, but it's the same idea.)

When I tried it, I discovered there was still some bass getting through to the front speakers. The reason (I discovered later) was that there were some frequency gaps between the equalizer bands that were still coming through. The EQ automatically adjusts the bandwidth ("Q") of a frequency as you drag it farther and farther away from 0, and when it's been dragged too far from 0, then the Q is too narrow and there are some gaps between the bands. So if you want to do this, then you have to manually adjust the Q for the frequencies you want to cross over.

Then, after tweaking the Q to cover the proper range, I realized I only had four bands left over to actually EQ the front speakers. Although they are fully parametric, it's hard to get the sound "perfect" with only four bands when you've got no visual feedback about what you're doing the frequency and the Q. But I did my best and it sounded OK.

But anyway, after all that, you can only reduce a give frequency by 30db or so. This isn't exactly the same as a crossover. So although things sounded OK, it wasn't completely what I wanted.

In the end, I just purchased some F-MODS from Crutchfield. These are cheap little RCA plugs with a fixed-frequency crossover built into them (you choose which frequency at the time you order the F-Mods). I used those to cross over the amps. Worked like a charm, and no stray frequencies. Then I was able to use the EQ for what it was intended: fine-tuning the response curve to match the speaker's characteristics.

Now I'm no longer using those old amps and I've got nice amps with built-in crossovers, so I'm not even using the F-Mods any more.

All in all, I think that just getting an amp with a built-in crossover is your best bet. Any subwoofer amp worth anything would have a crossover. And failing that, just get F-mods.

Now, the idea of having the fader control the subwoofer is an interesting one, even if you don't use the EQ to cross it over. Since I have carefully adjusted my amp gains so that the fronts and rears are equally balanced, there's really no reason for me to have a fader (unless I'm debugging a speaker wiring fault or something). So one day I might re-arrange my wires to allow this.

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Tony Fabris