To the other posters: it is clear that the OP wants pretty much everything ready to go. He just wants to throw some drivers into pre-made boxes and be done with it.
OP: I know exactly what you want. There are appropriate pre-fab sub boxes available. You should add in some braces(this is not hard; just buy a cheap mitre box with manual saw and buy some 1" x 4" oak boards from your local Lowe's or Home Depot. Please refer to bottom of this post for details on bracing.
Budget will be about $2300 total in the end.
I presume you desire compact size cabinets with very high output potential with very low distortion, and this is the premise for this post's instructions/parts.
Parts Express has the appropriate pre-fabbed small sealed boxes to start with, Part No. 302-810 ($160 each/ free shipping). It has a textured black finish pre-applied. You only need to cut a hole for the driver(using a cheap jig saw), add some *bracing and install a speaker wire connector plate/terminals.
You are going to have to go with a driver that has top notch objective performance. You simply can not go with a lower cost driver for a sealed application if you want high performance. Go with JL Audio 12W7. In reality, this driver will produce 2x the output of most high quality 12" drivers(430+56 shipping = $486 each), and it will do so in a small box, and with very low distortion.
Use this link, but call and have them physically verify they have 2 units in stock before you order. I have used them before - but you MUST verify stock before ordering. Don't trust the online stock counter.
http://www.sonicelectronix.com/item_4007_JL+Audio+12W7-3.html
For the amplifier, you need around 1000Watts minimum to get high performance in a sealed cabinet with this driver. For a solution that needs no modification for fan noise, the Yamaha P7000S($696 w/shipping) should work fine. It outputs almost 1k per channel x 2, 20Hz-20,000 Hz into 4 Ohms.
Buy from here(top notch customer service):
http://www.zzounds.com/item--YAMP7000S
To save $54 dollars, get zzounds.com to price match this site:
http://www.djdeals.com/yamahaP7000S.htm
To submit price match request to zzounds.com for the P7000S, use this webform:
http://www.zzounds.com/spy/supplier_item_id--23162
For the xover/DSP processing, use a Behringer DCX2496($268 w/shipping).
http://www.zzounds.com/item--BEHDCX2496
To save $32, get the zzounds.com to price match this site:
http://www.djdeals.com/behringerDCX2496.htm
To submit price match request to zzounds.com for the DCX2496, use this webform:
http://www.zzounds.com/spy/supplier_item_id--21573
The DCX is not optional. You must have both a proper flexible crossover and you must be able to enter parametric band filters to get the low frequency flat response. This is true for all high performance sealed systems; they have built in processing. But we are simply using external components.
The above will give superb performance, down to about 20Hz. Using carefully analyzed EQ settings (chosen based on power vs. excursion safety vs. optimal flat response), the anechoic response will be about -3 at 32Hz, -6dB at 22Hz. In room response will boost the LF a bit, giving essentially flat in-room response to 20Hz, with the above drivers, cabinets and using my specified settings for the DCX2496.
Use these settings:
-Parametric EQ: Frequency=22Hz, Q=2.0, Gain= +3.5dB (This extends LF response)
-Parametric EQ: Frequency=85Hz, Q=0.5, Gain= -2.0dB (This flattens out the inductance peak)
-Crossover: whatever is appropriate for your system.
* To brace cabinet, you will knock out the single cross brace in the cabinet. Just use a hammer to forcefully remove it. Use the 1" x 4" oak and install it all the way around the inside of the enclosure, at least 2 sets of ribs down the depth of the cabinet. Install a couple of ribs on the back panel, also. To install the ribs, use PLH polyurethane construction adhesive. To temporarily hold the cut oak in place while the PLH sets, use 3-4 1" pieces of commercial grade 3M double sided foam adhesive per rib. The PLH adhesive is the strongest such adhesive of which I am aware. It is substantially superior to Liquid Nails commercial adhesive in terms of strength. I can provide some basic illustrations if the above description is not sufficiently clear. You may have to cut out some clearance from the ribs where the 12W7 motor initially sets down into the cabinet; the motor is huge. Use a cheap jigsaw to cut the clearance slots, if needed.
-Chris
