Pharmer81

I've got a 2003 F150 extended cab and will be building a box to fit under the 20% driver's side rear seat. I've been trying to decide between a JL 8W3, JL 10W1, and ID8 V.3. After doing some ready and talking to a few people, I'm sold on ID subs. I'm getting ready to order and ID8 v.3 d2 from woofersetc. I chose the 8" due to mounting depth limitations. The box will be approximately 13.5" in length, 12" deep, and 7.75" tall, and will be a down-firing enclosure. I will use 3/4" MDF for the sides and 1/2" MDF for the top and bottom to allow for maximum mounting depth. My first question is: how much room should I leave for woofer excursion? If I hold the mounting surface of the box 1" off the floor, I will end up with 5.75" mounting depth. How much room do I need to leave for this sub to prevent it from smacking my floor? If the mounting depth of the sub is 4.75", how much free space needs to be at the base of the magnet to allow the sub to function properly?

See the third post for an update on my amp selection.

GATORB8

That eclipse is a lot of power for that 150RMS rated sub.

Regarding the subsonic filter, since your not running a ported setup I wouldn't worry to much about it. Most music doesn't have much content that low anyway.

I'd try to find a little 50-75W RMS x4, bridge the rear channels for the sub and run your front doors (even stocks) off of the front channels.

Pharmer81

The guy at Image Dynamics recommended an AB amp over a class D for SQ. I've got my eyes on an MB Quart RAB 1450. MB Quart RAB-1450 (rab1450) - Monoblock Car Amplifier, Power Amp - Sonic Electronix
It looks like this one should do the trick. Anybody with experience with these amps?
I'm pretty happy with the sound my deck is making with my Polk speakers, so I don't feel that I need to amp the fronts for my needs.

joefox

Watch out with Eclipse equipment since they are no longer in the aftermarket car audio business.
Did you look at this amp?
http://mobile.jlaudio.com/products_amps.php?amp_id=576
It's tiny and is easy to fit under seats.
If you bridge half on that sub you will have 200w RMS. and 100w per channel for your highs will be plenty of power.

GATORB8

Are you going to be able to high pass your door speakers with your head unit?

That amp looks like it'll work fine. I assume your going DVC 4 ohms wired for a 2 ohm amp load?

EDIT: nevermind, just saw you're going with the d2, are you gonna run 4 ohms or 1?

Pharmer81

Yep, my deck has the hp crossover for the door speakers. I was planning on doing the D2. The guy at ID recommended overpowering an ID8 with as much as 600 watts RMS as long as the gain is adjusted correctly on the amp. I figure it gives me versatility. I can try it at 4 ohms and if I need more, run it at 1ohm, or start with 1ohm and step back to 4 if necessary. The damping factor of the amp was also mentioned to me as something to look for, but this spec doesn't seem to be consistently listed for all amps, and I can't find it for the MB.

Pharmer81

I just scored a deal on an amp. Boston Acoustics GT-40 for $43 shipped! I stumbled upon it and remembered the recommendations to buy a four channel and run my fronts off of two channels and run the sub off of the back two. This one is capable of 3 channel operation. 55 watts RMS at 4ohms to my Polk 6x8's and 245 watts RMS to the sub at 2ohms. That should sound nice. If it doesn't, I'm not out much for trying.