Just built a box and I'm not happy with it...

[East 10+ year member]

SETUP:

2 FI BTL NEO 18's
WOLFRAM 4500.1 @ .5 OHM
(4) XS 3100's
Mechman 320
(voltage stays around 13.5-14v)
04 Yukon SLT

BOX:

12.5ft^3
(4) 8" AERO 22" (200IN PORT)
TUNED 36HZ
4" FROM HATCH

So my system slaps the lows nice but that seems to be about it... I'm not very happy with it and I feel its the enclosure, my single 18" seemed to hit highs much better. I was told more port area was good for numbers so I went with 4 ports and figured I'd plug one for daily. Well... my system only hit a 148.1 and I was told by many a 150 should be EASY with my setup. What am I doing wrong? My box is really close to the hatch, about 4" away i'd say... and when I plug a port it seems more responsive and slaps lows but I lose 1db when I plug a port. There has to be a way to hit a 150 in this thing and hit highs better. Is my box too close to the hatch? why am I not hitting highs when tuned to 36hz? is my hatch acting as an extension to the port lowering tuning? how far is optimal distance for my configuration?

I want to build a new box to achieve a 150 but I don't know how to hit the highs any better, even at 36hz tuning a 40hz tone seems very quiet, but if I play 32-36hz my car falls apart from the lows. Don't get me wrong I like lows, but I'd also like some head hurting highs as well. Anyone have any ideas of what I should change? Just doesn't make sense, I have a good amount of power, high tuning and a **** ton of port area... Could it be that my box is just too close to the hatch? or am I missing something?

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[Jeffdachef 5,000+ posts]

Im pretty sure you have already done this but just in case, raise the LPF on head unit and amp.

Now to your issues, you can try shrinking the box by adding space fillers, along with using singular big giant octoport over multiple small aeros.

List your length x width x height, number of baffles, amount of bracing used, wood thickness etc..

 

[Boomin_tahoe 5,000+ posts]

And a few pics if you can.

 

[THATpurpleKUSH 5,000+ posts]

I would move it a little further from the hatch. Is the box single layer all the way around? Doible baffle? 45s inside? A single large port is way more efficient than multiple small ports.

 

[MattinMO]

have you clamped it yet? were you running the single 18 on the wolfram 4500?

 

[THATpurpleKUSH 5,000+ posts]

I just did the math on your tune.

If the airspace is correct at 12.5 then 4 8inch aeros 22 inches long makes the tune 39.45hz not 36hz. The ports would need to be 27.5in long for a 36hz tune.

With a tune at 39hz you should be able to play high notes well and not so much the low notes. Sounds like there could be cancellation somewhere.

 

[East 10+ year member]

I just did the math on your tune.

If the airspace is correct at 12.5 then 4 8inch aeros 22 inches long makes the tune 39.45hz not 36hz. The ports would need to be 27.5in long for a 36hz tune.

With a tune at 39hz you should be able to play high notes well and not so much the low notes. Sounds like there could be cancellation somewhere.

When you factor in displacement, the fact it's all double braced etc. Torres Box Calculator shows 36hz. There are no 45's and it's double baffled all the way around. The output is not NEARLY what I expected it to be. I understand less ports is better, which is why I'm debating on building a smaller box further from the hatch only using 3 aeros instead of 4. I noticed if I plug an aero it plays much flatter and sounds better, but its lower by 1db on the meter. Something doesn't seem right, this thing should be banging much harder I feel like. I was running a single 18 before @ 1 ohm and it was nearly as loud as this setup, I figured I would be hitting 150's with ease with this much port area tuned to 36hz... Not a 148. I'm not sure what it could be other then too close to the hatch or something?

 

[East 10+ year member]

have you clamped it yet? were you running the single 18 on the wolfram 4500?

I havn't clamped it, I was running a single 18 on the 4500 @ 1 ohm. Now I'm running 2 on the 4500 @ .5 ohm, I figured it would be alot louder but its only a little louder. I'm wondering if its just rising really high? maybe im not seeing much power?

 

[shredder2]

it's double baffled all the way around.

View attachment 19091

Double walled all the way around?.. or just double baffled?
If double walled Torres ought to look like this and it might explain your output problem.

4 ports above ^^^^... 3 ports below...

 

[Popwarhomie 5,000+ posts]

Yeah that doesn't look like 12 cubes to me just looking at it.

 

[East 10+ year member]

Double walled all the way around?.. or just double baffled?
If double walled Torres ought to look like this and it might explain your output problem.

4 ports above ^^^^... 3 ports below...

Yes it's double baffled all the way around. I see what you mean, but I added the baffles after the fact, the Torres calculations are correct to what my image shows. It's indeed 36hz and 12.5 cubes. So that is not the issue, it's playing lows not highs anyways so that wouldn't make sense.

 

[East 10+ year member]

Yeah that doesn't look like 12 cubes to me just looking at it.

How do you figure? It takes up the whole back of my Yukon and goes over the seat a bit, it's def 12.5 cubes. Torres Calc states so, so i dont see how it's not 12 cubes? I used like (8) 4x8 sheets to build it. The box is 21.75 x 48 x 32 , put that onto paper you'll see it's 12 cubes.

 

[East 10+ year member]

Don't get me wrong the thing is loud, but its mainly only playing lows... I'm not hitting **** for decibels and I dont think it has to do with size or tuning, I think theres something else holding me back, either not enough space in the rear or too much rise? everything else seems on point, this thing should be shitting out 150's.

 

[Oldmang]

I'd try finding your tuning in cabin with a tone generator and see how much the port clearance and being in cabin lowers the targeted tuning.

 

[Boomin_tahoe 5,000+ posts]

Who designed and built that enclosure?