Port Area for 12" Bl

[4X4AUTIGER 0]

alright so ive had my 12" bl and sundown saz 1500d in a 2 cuft box wired at 1 ohm for about a week now and its not as loud as i expected. its a great sub dont get me wrong but it really doesnt get loud unless i turn on my loudness control on my headunit to atleast low and turn my eq settings on super bass... but i thought i read somewhere that you should not do either of these things... i was checking out my box that i had custom built and the port area was only 3.5" x 4"... isnt this a little small? i thought the port area should be from 32-24 square inches since the box is 2 cuft. would this make my setup louder?

[jcarter1885 995]

What are you settings on your headunit at, and what are your settings of your amp at (how did you set the gain, also)?

[4X4AUTIGER 0]

What are you settings on your headunit at, and what are your settings of your amp at (how did you set the gain, also)?

the gain was set right (i watched the man do it). LPF almost half way, subsonic alomst half way, bass boost looks turned up a little (shouldnt i turn this down to none?) phase is not turned up at all... HU: loudness at low and eq at super bass

[4X4AUTIGER 0]

but is my port area too small? would it hurt the driver? or is it not a big deal... oh and the box is tuned to 35.5Hz

[KU40 173]

If the subsonic is almost halfway it's around 35 hz. That's too high and is cutting off a number of usable frequencies. Try turning it down to maybe a little over 1/4. Also with the lowpass almost halfway it's around 160 hz. Waaaay too high. Turn it down to 1/4, or maybe where 80 hz might be. Turn the bass boost all the way down. Put the loudness on HU off and put the EQ on whatever you like the interior speakers to sound like. Then reset the gain.

[4X4AUTIGER 0]

If the subsonic is almost halfway it's around 35 hz. That's too high and is cutting off a number of usable frequencies. Try turning it down to maybe a little over 1/4. Also with the lowpass almost halfway it's around 160 hz. Waaaay too high. Turn it down to 1/4, or maybe where 80 hz might be. Turn the bass boost all the way down. Put the loudness on HU off and put the EQ on whatever you like the interior speakers to sound like. Then reset the gain.

sounds good but is my port area okay? maybe i should wait for mdmustang to answer that... also since my sub is inverted should i set my phase control to 180 degrees?

[shizzzon 461]

having your sub inverted may be part of why it's lacking...

For daily use - You would want 32sqin for that box.

Personally, i would want that box in 2.2-2.5cubes NET with 40sqin of port.

[4X4AUTIGER 0]

having your sub inverted may be part of why it's lacking...

For daily use - You would want 32sqin for that box.

Personally, i would want that box in 2.2-2.5cubes NET with 40sqin of port.

okay i think it was 2 cuft after sub and port displacement and that was the max i could fit under the seat... i will make the guys build me a new box.. but should i expect any db gain?

[shizzzon 461]

from your port area, yea, you'll definitely have an increase!

From your box itself, u need about 3.5-4cuft GROSS to get great output from a 12. See if 32-40sqin can work for your box.

Or... just for fun, give me your max dimensions and i'll tell\show u what can fit.

[4X4AUTIGER 0]

from your port area, yea, you'll definitely have an increase!

From your box itself, u need about 3.5-4cuft GROSS to get great output from a 12. See if 32-40sqin can work for your box.

Or... just for fun, give me your max dimensions and i'll tell\show u what can fit.

i have 2.6 cuft gross box... why would i need a atleast 3.5 cuft box? the driver is .18 cuft and the port will be about .5 cuft so the volume after displacement will be 2 cuft

Edited October 5, 2009 by 4X4AUTIGER

[4X4AUTIGER 0]

well i looked at the specs of the box the installer drew... my port was supposed to be 30 square inches but the installer must have miss cut it and made it only 14 square inches... so instead of being 35.5hz its 23hz

[4X4AUTIGER 0]

well i looked at the specs of the box the installer drew... my port was supposed to be 30 square inches but the installer must have miss cut it and made it only 14 square inches... so instead of being 35.5hz its 23hz

so i talked to the installer and he said if i used 32 sq in of port there would be a lot of port noise... is this trure?

[KU40 173]

Wait, he said if you use more port area there would be port noise? Do yourself a favor, never go back to that shop again. He has no idea what he's talking about. A smaller port, such as yours that he made at 14 sq. inches, is where port noise becomes an issue.

You need a larger port to move more air. It's like trying to move 1000 gallons/minute through a 1" pipe (14 sq. inches of port) vs an 8" pipe (35 sq. inches).

[porkchop 304]

new box time..... that sub / amp combo should have no problem pleasing you, it is all in the math goof-up, on their part.

[jcarter1885 995]

well i looked at the specs of the box the installer drew... my port was supposed to be 30 square inches but the installer must have miss cut it and made it only 14 square inches... so instead of being 35.5hz its 23hz

so i talked to the installer and he said if i used 32 sq in of port there would be a lot of port noise... is this trure?

Your builder sucks and theres a reason why he reduced the port in the first place because he doesnt know what he is doing, after you said he set your amp and you watched him do it shows how local shops fuck people over and just cause they are their watching, makes that person think they know what their doing. Thats why all you settings on your amp are off, he needs to stop installing ASAP!

Build a better box, LPF at 80Hz or lower, SSF on 1/4 turn or a little higher, may need to play with phase after you set amp up correctly (use DMM to set your gains, look in the Amplifers, Headunits, equalizers thread and check out the Amp Gain Settings Topic). Turn Loud off on radio and Eq to your likings on head unit. Good luck.

[ppiflat10s 3]

I would try and get them to build the right box for free since they decided to go ahead on their own and change the box design you gave them without consulting you about it...

then never go back there

[4X4AUTIGER 0]

I would try and get them to build the right box for free since they decided to go ahead on their own and change the box design you gave them without consulting you about it...

then never go back there

yeah they def will... they have great customer service

Edited October 7, 2009 by 4X4AUTIGER