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


East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
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 shit ton of port area... Could it be that my box is just too close to the hatch? or am I missing something?
 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,821
470
South Coast Metro, CA
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..
 

THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,617
531
Banging gears and passing queeers
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.
 
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OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
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?

19088
19089
19091
 
OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
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?
 
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OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
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.
 
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OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
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.
 
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OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
Don't get me wrong the thing is loud, but its mainly only playing lows... I'm not hitting shit 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

CarAudio.com noob
Aug 11, 2019
37
15
Az
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.
 

Popwarhomie

Team Lethal Pressure
10+ year member
Jan 22, 2010
6,876
573
Florida
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.
Not when you change your wood size from .75 to 1.5 like it is. I’ve done multiple 12-14 cube two 18 builds. For it not playing high I couldn’t tell you. I always tuned to 35ish and peaked in the mid 40hz range. I would guess you wouldn’t be playing low enough if your ports were being choked by the hatch. I would double check your LPF on headunit and amp. Then clamp your amp and see what you are getting for rise.
 

MattinMO

Senior VIP Member
Dec 31, 2017
729
136
St.louis, MO
hmmmm, fold your back seats down and push the box as far forward as you can go just temporarily to see if you are getting some port choke. when you wired the amp down to .5 did you set your gain again as it might of walked a little
 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,821
470
South Coast Metro, CA
just a test, open the hatch and play the subs and see how it sounds up front. Also are your subs in phase?

Also with your design you have TOO MUCH damn port area. keep that shit at 8-13 port per feet for aeros. You cant build pressure like that. Also why you lost DBs is because you lowered the tuning by taking away the port area while keeping the length. If you made the ports shorter and took off one port, you'll be louder. You can lose cone control with too much port area the box will basically act like its Infinite baffle. Which is what happened with my old setup with 4 18s, I lost a lot of output and bandwidth when I had all 4 10 inch sonotube ports open. I gained more and more as I covered the ports, night and day difference in output. But i had to shorten the ports as well to keep the tuning.
 
OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
Not when you change your wood size from .75 to 1.5 like it is. I’ve done multiple 12-14 cube two 18 builds. For it not playing high I couldn’t tell you. I always tuned to 35ish and peaked in the mid 40hz range. I would guess you wouldn’t be playing low enough if your ports were being choked by the hatch. I would double check your LPF on headunit and amp. Then clamp your amp and see what you are getting for rise.
I explained already that I figured out the double baffling without using the program parameters. Meaning the program is correct, I added a shell on the outside of what the program says, so those are correct numbers. IT'S 12cft, theres no doubt about it. I checked my LPF over on everything tuned it as I would. I need to clamp my amp tho you're right.
 
OP
East

East

Team New England
Sep 27, 2012
267
0
Fryeburg, Maine
just a test, open the hatch and play the subs and see how it sounds up front. Also are your subs in phase?

Also with your design you have TOO MUCH damn port area. keep that shit at 8-13 port per feet for aeros. You cant build pressure like that. Also why you lost DBs is because you lowered the tuning by taking away the port area while keeping the length. If you made the ports shorter and took off one port, you'll be louder. You can lose cone control with too much port area the box will basically act like its Infinite baffle. Which is what happened with my old setup with 4 18s, I lost a lot of output and bandwidth when I had all 4 10 inch sonotube ports open. I gained more and more as I covered the ports, night and day difference in output. But i had to shorten the ports as well to keep the tuning.
I was told for numbers more port area was better why I went with 4 and plug one for daily. I agree though that I think part of my issue is there is too much port area. I will be going with 3 ports in my next box build.
 

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