Upgrading to a powerful system (1500+ watts)

I just got one idea... A Sundown Audio SAE-1000D is $285 shipped and an Fi Q15 is $279 shipped or an Fi Q18 for $309 shipped

 

Yeah I'm thinking the SAE-1000D and the Q18 sealed for $594 plus like $60 for the box. If I can sell my stuff for $550 then I'd say that's a great swap of systems. I bought my 2 amps and 2 subs for $520 new and it cost me probably $60 for the box.

 

Okay I'm trying to decide between the Q15 and the Q18.

Q15:
Sealed box: 2-2.6 cuft
Ported box: 2.8-4 cuft @ 28-33Hz

Q18:
Sealed box: 4-8 cuft
Ported box: 6-10 cuft @ 28Hz

I could do a Q15 ported or sealed, a Q18 sealed, but I don't know if I could do a Q18 ported and keep my spare tire. What do you guys think I should do?

 

Alright I did some math for the Q18... even if I got rid of my spare tire, to have a box 37" wide, 21" tall, 24" deep, a port 4.75"x19.5" and 45.25" long (92.625 sq. inches of port), a double thick baffle, no other bracing, and a sub displacement of .24 cubes, the best I could get was 5.26 cubes after sub and port displacement.

 

Not yet. My friend wants to buy it though. I can fit an 18" sub.. sealed only though and probably no more than 5 cubes in order to keep my spare. I'm not sure if I can fit a 15 ported. I don't think I can do 4 cubes ported and keep my spare (because of so much port displacement to tune it to 28-33Hz). I can probably do the minimum volume requirements.

 

I'm looking at outside dimensions of like 37" wide, 21-22" tall, and 14" deep. If I can, I'd like to drop the height a tiny bit to let the waves come back. I think Fi recommended like 15-16 sq. inches of port per cube. I think 4 cubes @ 28Hz with that much port displacement is going to be hard. I can probably do the minimum requirements though of like 2.8 cubes.

 

Okay I think I can do 3.25 cubes at 33 Hz for the Q15.

 

(20" tall)

 

they will come? lol

 

But seriously, does 3.25 cubes @ 33 Hz with a port 2.5"x18.5"x30" long sound right for the Q15?

 

Okay, do you think the box has enough bracing with the double-baffle and port walls?

 

Alright I'm going to increase the height an inch and do some front to back and top to bottom bracing. How long does the port need to be if it's 2.5"x19.5" (3.25 cubes @ 33Hz)?