View Full Version : Ok I built my box, now I have some questions.

11-27-2004, 05:15 PM
Ok well I managed to get through the box building. I cant beleive I was able to pull that off. Well its a box for 1 12' SX. I have a JBL 600.1 amp. To my best attempt, I have the box at 2.5 CF and tuned to 35hz. I have a port of 3 inches in diameter and 4.1 inches long. But I am getting alot of port noise. If i jumped it up to a 4inch in diamater port, would that help or any other suggestions. Also on certain songs or bass notes, the sub makes some sort of fluttering noise, im not sure what that is. but im sure i didnt do something right..any suggestions would be appreciated.

my thoughts is thats its louder then my 2 12inch kicker comp vr's that were in a sealed box. sounds pretty decent too...cant tell too much about sound quality due to the fact its ratteling the hell out of my car, trunk and tags and the back panel where the back speakers are on.....

11-27-2004, 05:40 PM
go a 4" by 10"long. it'll bring tuning down to 33, it will rid you from alot of the port noise.

11-29-2004, 04:24 PM
Ok I will try that, thanks for the reply.

11-29-2004, 04:26 PM
Fluttering noise is most likely just port noise, either that or you are near exceeding its mechanical limitations. I would recomend putting a sub sonic filter on there just in case.

11-29-2004, 04:48 PM
i just ported my 2 cuft with 4" diameter, port length 11.5" PVC pipe, and still port noise, its in the trunk, u dont notice it in the cabin though.
@35hz also..... for single ts-2000spl (12")

11-29-2004, 06:38 PM
hey chad what made you stay away from REs 35 hz box? i called them and they said it was okay, just 30 hz was wrong.

11-29-2004, 06:45 PM
well I dont hear the noise in the cabin, but if i pop the trunk, it can be pretty loud..

bama, i did stay at 35, it was recommended to me from another post to drop to a 4 by 10 port and down to 33. this was my very first box and im surprised I did it. i havent tried that yet, I still got the 3 by 4 port. have you finished your box yet?

11-29-2004, 06:49 PM
7 square inches of port is not nearly enough for a 2.5^3 net enclosure. I would suggest a bare minimum of one more 3" port, totalling ~14 sq ins... and you'll still get chuffing depending on power level.
even better (2) 4" diameter pipes for ~25 sq in's of port.

11-29-2004, 07:10 PM
So if I have one 3inch in diamater port at 4.1 inches(as what was recomended from http://www.the12volt.com/caraudio/boxcalcs.asp#par), if I added another port of the same exact size, what would be the tuning of that. That may be easier, I still have the 3inch port laying around. Would have to go buy 4inch ports if I went that way.


11-29-2004, 07:11 PM
no i havent started my box tomorrow afternoon im gonna start cutting and wednesday im getting SX. What i mean't is what happen to the slot port idea from re the one on their site

11-29-2004, 07:17 PM
bama I didnt do the slot port, because the box dimensions provided by RE was too wide for what I wanted, so I made my own dimensions to fit the 2.5 cf. I would of went with the slot port but I would of had no idea on how to reconfigure how long, wide and the specifics of the port based on the new measurements I had for my box. was much easier for me to say just throw in a circular port of a certain length..

what amp are you going with, even though I only have the 600 watts, it still gets pretty dang loud. I have a headache just from driving from home to work.

11-29-2004, 07:19 PM
Well IF:
Your pipe is 3" with 1/8" wall, and 4.1" long, and you're using 3/4" mdf... then your pipe displaces .016 cu ft?
If you add one more just like it you will lose another .016... meaning a net vB of 2.48..
And your tuning would be: 46.1hz.
Again, you'll prolly still have chuffing.

To get lower, make the port longer.

To get 35hz with (2) 3" {1/8" walls} you'll need a depth of: 9.625" on both of them. Also, these would bring your box volume down to: 2.43 cubes.

Hope this helps....


* and you'll prolly still get chuffing with 600wrms.

11-29-2004, 07:43 PM
I really appreciate the your time and answers...but

is "chuffing" port noise or is that what I was experiencing with my sub? do you think if i use the 2 ports at 9'6 each, will that still pretty much sound the same as it sounds now. if i will still get chuffing, whats the benefit of going to 2 ports.

thanks again

11-29-2004, 09:19 PM
chuffing is another term for port noise, sorry.

if you go to 2 3" ports it'll be alot better then it is now. but... when you put all 600watts into it you are most likely going to hear the noise again.
not only is the noise annoying, its not really good for the woofer, pretty much the turbulence "pools up" and blocks the port. then you effectively have a 2.5' sealed.

gimme a minute.

11-29-2004, 09:22 PM
have you thought about slot port? just a thought but if you already fixed it then have fun man

11-29-2004, 09:30 PM
mmkay, if you go to (2) 4" pipes, each with a depth of 24" you should have no problem upto ~900wrms. This would also drop your box volume to ~2.1^3.


you could do (1) 5" aeroport with an end to end length of ~16.25" and be good upto ~700wrms. This would drop your box volume to ~2.3^3.

I would prolly go option #2.

hope this helps...


11-29-2004, 09:55 PM
thanks for the input...my box is about 15' in depth. so that wouldnt work..I will probaly try the 2 -3 inch ports and see how that goes.


11-30-2004, 12:16 AM
you can use 90* elbows. just make sure to measure the length properly and no problem...