BKOLFO4

If you add a second sub and cut your power in half, you are not going to see much gain, if any. You might get a little gain from less power compression, less heat, and you might not actually cut the amount of power you are seeing from the amp exactly in half.

Even if the gains/crossover settings are a little off, it WILL NOT hurt anything. . .

I run the MTX 12" shallows in my truck and they are awesome. Using an AQ2200 at 1 ohm and they take it like a champ! Been in the truck 33k miles now and still going strong.

Sorry - I have not been on the forum in a day or two. PM me some dimensions from your trunk and an email address. I can help you.

Recones have always taken forever for me. I just let customers know up front. It is a secondary business. As someone stated, they have been moving for 2 weeks. I would give them another week and you should be able to contact them. . .

Ha! It drives me nuts!! Every answer over there is 12-16 sqin per cube! I just like giving Mike a hard time. . .I've learned a lot from him through the years!

Haha. There you go again talking about things you know nothing about. Just visit the SMD forum - they will let you know you can't even begin to determine the amount of port area required without knowing how big the box is going to be. And don't even think about doing over 16 sqin per cuft - that is reserved for SPL applications only. Oh - and less port = better lows, more port gives you better high bass. If you can't remember these basic rules, just download everyone's favorite calculator over there - it figures all this out for you. Just keep reading my friend, you're learning.

I am going to run mine in 2.8 cuft tuned to 32 Hz with 40 sqin of port.

45-50 sqin of port would be nice for 3 of them. There really is no need to tune those 8's that low. I have not modeled them lately, but I would think you could tune a little higher without a big hump in the response. Not sure what you consider high bass, but anything over ~60 Hz will be controlled by your low pass filter, not the tuning frequency. The tuning frequency does not control the upper bass response, but what it can do is cause a peak in the response around and right above tuning that is quite a bit louder than everything else.

Man I love Mayhem subs. This one is going in 2.8 cuft tuned to 32 with 50 sqin of port. Massive Nano N4 (2000 RMS) for power.

That amp would destroy a pair of XXX 18's. Mayhems are another great choice.

Good answer helotaxi. You need both, but if I have to choose, I'll do more batts first. You just have to keep an eye on the voltage an allow the batts to replenish as the voltage drops. I ran the stock alt with 4 batts in my suburban for 2 years with 8000 watts. Did a single 250 amp alt and 9 batts with 17000 watts for another 2 years. My Astro was a single 250 amp and 15 batteries for 25000 watts. . .

Email Shawn at Fi. I am sure they will send you one for a few $$ to cover the shipping.

6.5-7 cuft tuned to 32-33 Hz with 90-110 sqin of port area. The exact design would come down to the box dimensions.

Don't forget, SP4 is not available in a 12".