HI guys..i use to be a spl competitor, and after selling my car..and getting a new one...i needed some bass..daily bass!

So i build a ported box for my 2-12" audiobahn DUB speakers

PROBLEM: the box seems like its tuned too high. I listen to rap music..and it just not hitting the lows....Can someone look at these thiel specs..and maybe pop it into boxplot and let me know what the reading says - I got and used box plot..but I must not be understanding the readings?

I just spent 13 hours straight (9am - 3am) installing my system, building the box, building the amp rack! and now this!

box is - 15" x 15" x 31.75 using 0.75" MDF wood (Internal volume: 3.19 cu.ft), vented with 2-4" x 10.5" round ports. I also lined the box with 2 layers of Polyfill

SPECS:
FS: 32hz
QTS: 0.72
QES: 0.83
QMS: 5.397
VAS(litres) 63.99
VAS (cu.ft) 2.26
RE: 1.5 ohms
LE: 0.43 mH
Mmd: 126.5 grams
Xmax: 8mm
RMS: 400 watts
Sd: 480 sqcm
Freq. Response: 20hz-500hz
Efficiency: 92.7 db

THANKS SO MUCH for whoever helps me out!!!!!

 

one more thing..im using a 800 watts amp to power them

 

Your box seems to be tuned to about 43hz and I didn't take polyfill into account (might be a bit lower). You would need a longer port to tune lower. You can get a 14 inch long port and that should put you into 37-38hz region. Plus the polyfill might help.
Because you have 15" on the face where the port is, as far as I understand, you shouldn't go above 14" for the port.
That's my take on it. Other ideas welcomed.

I'm not sure if you really need 4" round ports. Maybe you can get away with 3"? I need to look this up in winisd, but it's early morning and I want to have some breakfast first .

 

So Strange. Im having the Same Issue.
Box is Almost exact same, With 4" by 13" long.
2lbs of Polly fill.

It just wont hit the Lows.

2 OZ 12" at 500RMS each.
Using my T3-500D for testing.

 

DF DIMA - hopefully you can pop it into WINSID..and see what it says...thanks...

also how can i make the port longer?

 

I am also thinking of inverting the subs..to get the more volume in the box free! ANy losses with inverting subs?

 

I popped a 2 - 3"x10" ports into BASSBOX 6 pro...and it says the tuning will be 32hz...

How does that sound for RAP music?

 

^ 2 3" diameter ports is getting kind of small for a pair of 12s.

IMO the box is on the small side for a pair of 12s but since it's built already all you can do is try longer vents to tune it lower.

 

Well i put the 2 - 3" x 10" ports and it solved the problem...and no port noise

now some fine tuning and i will be done.

I am now gonna try inverting the subs to gain a little more air space in the box..see if that makes it even better!

thanks!

 

Your QTS value is a little high for premium performance in a ported enclosure. Ideally a QTS between 0.2 and 0.5 is recommended. Where did you locate your ports in relation to the drivers? Did you flare the ports?