sub vocals...

well u could make yur crosover lower, but some vocals could just naturaly have that low of a frequency that they would come out of the subs

It wouldn't hurt to check the outputs on the deck. I bought a new one and thought I hooked them up the way they were supposed to be, but I accidently hooked them up backwards and sound came through the subs, but it only took a whole 30 seconds to fix the problem though... I would start there and then try ryan's idea for sure..

If it were me, I'd knock the xover down at least some...depending on what your other speakers are capable of, I'd probably go down to about 80 hz or something around there. I am of the opinion that subs should really only be playing actual "sub" bass. Mine are crossed over at around 55-60 right now. The higher you get with them, the more directional the bass becomes.

If you just want a loud system, though, I suppose it doesn't really matter where you set the xover, as long as it's not at 500hz or something like that.

What volume (on the deck) do you normally listen to your music at? Having the bass boost set so high with the gain up where you said it is seems a little off to me.

If you need help actually setting the gain, the general rule is to zero out all the settings on the deck (EQ, bass boost, etc..) and set the volume to about 75% of it's max. Then start turning the gain up on the amp until you hear some distortion in the speaker, and back it down just a bit till the distortion goes away. Then you just don't exceed that volume on the HU.

Polyfill is one of those things that everyone has their own opinion on. Basically, the idea is that if you stuff the box with poly, it will absorb some of the heat put off by the sub, and fool the sub into "thinking" that the box is bigger. Some people swear by it, some hate it, and some just don't care. If you want to try some to see if you like it, it's not gonna hurt the speaker. And it's not like polyfill is terribly expensive.

Try the x-over around 80hz with a sharp db / octave slope (if your amp has selectable slopes). check the Hz level that the bass boost works at. If it's adjustable, play your favorite song and tweek the knobs.

Yes put some poly fill in the box it will give you richer bass. And everyone is right check your crossover

I'd also recommend lowering your crossover point. Joker's right about setting your gains, too. I also wouldn't put your bass boost that high. You're probably clipping the crap out of the signal. One question, did you get the dual 4 or dual 2 ohm version of the L7?