BMoney

I know I know, its very common - I've been asked to make a 91 CRX as loud as possible. Here's what I have sold to him so far:

(2) RE XXX12's
(1) Visonik 4000XD
(3) fullsize yellowtop batts
-- unlimited wiring/etc potential (using Raptor/Tsunami product)
-- car is fully damped - 2 layers of BrownBread on practically everything
-- enclosure will have a 1.5" thick baffle, rest of panels of 1" mdf and full bracing. Will also be resining the interior (airspace factors in all these displacements)

The goal is to have a very loud daily driver - so no CRX-style fart boxes will work. Heres some first questions:

1. for the box - subs facing up, and ports facing back right? or is it ports up and subs back? (I know its one of those!)
2. will having the subs closer to the middle of the car work better? or as close to the back as possible? or does it matter?
3. what is the "sweet spot" in a CRX? - to save me some redundant declining-port testing

I was thinking of a single shared airspace that will give each driver just over 2 cubes of air each (after all displacements) and share 4 x 4" Precision ports. I was hoping to be able to swap the ports out - so run "listening" ports that give the 4 cubes a tuning of about 35 hz, and then run a set of much shorter ports to put the tuning up around the sweet spot (I'm told its like 55 or 60 hz?) Also plan to have one yellowtop under the hood, with a pair of 1/0 runs to the hatch where the other two will reside, and feed the 4000xd right off of them.

Any ideas on using the above equipment to its fullest potential? I know the CRX is a well documented car - and I'd like to take advantage of some of that knowledge to make sure this works out well...

thanks!
bmoney

seege

iTrader: (1)

CRX's seem to vary a lot from car to car, and what works in one will not necessarily work in another. I tried Curtis Simanvicious's box in my CRX with the exact same subs, amps, and battery, and could only hit a 146.9 with it while he hit a 152.7 in his. (I used his exact box and subs, and we both used D3's and a hawker 1700). After about 30-40 boxes, I found that my CRX liked 62 hz with the subs facing sideways and the port facing back with external aeroports in a relatively small box. I also lost over 1 dB from adding damping (up to 2dB depending on the note, but every frequency lost).

Prolifik

iTrader: (7)

if u not doin spl just make a regular crx box and u good to go. tune it to like 32hz and dont worry about any sweet spots as those are redundunt unless u are doin 'far box' for spl. and in the crx the sweet spot is like over 60hz which is way too high for regular bass anyways.

also u dont really need to go 1" and 1.5" thick. not enough power to worry about that so u'd be wasting time/money and adding weight. with so little power 3/4 to 1 inch wont make any diff at all.

BMoney

interesting about the variances - and no, this is not an spl-only ride, but the intent is to try and do well with it on the mic By the sound of things, my initial assertion was pretty close - tune to mid 30's for listening, and then try messing with the ports to push the tuning into the 60's for "burping". thats the idea behind the temporary ports

this is good! anyone else?

bmoney

1LoudScort00

iTrader: (2)

I could be wrong, but I always thought tune higher for more SPL, is this true?

Prolifik

iTrader: (7)

1Loud, u are way off dude.

BMoney, that car should do upward of 147-148 with a good box if u guys use the gear properly. Im not sure where u are (i think mississuaga?) let me know if u need any help with makin that loud (the spl part of it). and u dont need temporary ports, i'd make 2 diff boxes b/c your musical box would be totally different from your spl box.

BMoney

hahaha mississauga - try Thunder Bay (you know that Yuli!) Customer doesn't want two boxes man - so we're gonna tinker with the ports instead. Knowing that my Jimmy did 144's with a single XXX15 (musical box) and 900 wrms, I can't see why this CRX (much louder ride) with a pair of XXX12's and 4 times the power shouldn't get a little closer to 150 I'm hoping anyway....

Any other considerations? I know that sometimes making the box a little smaller may enhance spl - what should I be shooting for in box volume to get about half-way between maximum extension and maximum output?? I tried for an hour over beer with the customer to run a pair of boxes (one to street beat with, the other to run the mic with) and he's totally against it. He's not willing to **** around with 65lb subs in and out of boxes all the time....and I don't blame him.

the product wasn't purchased with the express purpose of being an SPL vehicle - but clearly there is serious potential and I want to harness all of it for him....Yuli - when you say a "regular CRX box" you mean subs on top and ports on the back right?

bmoney

Prolifik

iTrader: (7)

i mistaked u for someone else.
standard crx box is 29 wide, 29 deep and 14.5 tall. 4 aero ports, make them whatever lenght u want for the box to sound good. ports fire back, subs fire up.

BMoney

being over 5 cubic feet, you obviously intend to run both subs in that airspace - and thats 4 aeroports per box, or per sub? I'd think 2 x 4" ports per driver should be enuf area no?

we're getting there! I'll try and catch you online tonite

bmoney

Prolifik

iTrader: (7)

both subs in that box
2 ports per sub