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View Full Version : Does Port Diameter Matter?



Jonahdude
10-15-2004, 02:16 PM
Say you have identical boxes, one with a 2" port at the proper length to tune to 35hz and another with a 4" port tuned to 35hz. Would either box offer more SPL?

tRiGgEr
10-15-2004, 02:20 PM
No - just less port noise and resistance which could result in a little increase in spl but not noticable.

Jonahdude
10-15-2004, 02:23 PM
So I might as well go with a single 2" diameter port that's 1.5" long, to tune to 35hz? That just doesn't seem right for some reason, I always see people use bigger ports. 2.35 net internal volume, I used this calculator:

http://www.the12volt.com/caraudio/boxcalcs.asp

tRiGgEr
10-15-2004, 03:12 PM
So I might as well go with a single 2" diameter port that's 1.5" long, to tune to 35hz? That just doesn't seem right for some reason, I always see people use bigger ports. 2.35 net internal volume, I used this calculator:

http://www.the12volt.com/caraudio/boxcalcs.asp

No. What is the size of your box, after speaker displacement. What speaker are you running, What kind of power will you be running.

Jonahdude
10-15-2004, 03:21 PM
I'm building two indentical boxes, one on each side of the trunk. After displacement, the volume is 2.35 ft^3 each box. I haven't built the boxes yet, but that's the plan. External dimensions are going to be 13x13x35. I'm running 3 MTX Terminator 8" subs in each box, and they're going to get around 100w RMS each.

tRiGgEr
10-15-2004, 03:37 PM
A port 11.5 x 2 x 18.5 would work with that box. tuned around 35hz

Jonahdude
10-15-2004, 03:40 PM
How would I make it?

tRiGgEr
10-15-2004, 03:49 PM
How would I make it?

With wood??????????????????????????????????






















Ok your going to use one side of the box as a side of the port. Just build the port on the side. Have it bend in to the box at the corner. And keep the port area constant all the way threw.

Jonahdude
10-15-2004, 04:05 PM
I can't picture what it is you're talking about... do you have a picture of something similiar?

Jonahdude
10-16-2004, 03:11 AM
bumped ttt

BASS OUTLAW
10-16-2004, 06:49 AM
well i didnt challenge in an SPL comp b4 , but i ve seen many SPL ports, it always got larger area.

Jonahdude
10-16-2004, 10:56 AM
Well I'm not really trying to make an SPL box, I know I asked which one would have more SPL but I actually want more SQ than SPL.

Jonahdude
10-16-2004, 02:49 PM
I want it to have more SPL than a sealed box, but not lose sound quality, if that's possible.

jemorgan85
10-16-2004, 02:52 PM
No - just less port noise and resistance which could result in a little increase in spl but not noticable.

So you are telling us that less effective port radiating area would not be a big deal.....?

You ever competed before?

DBfan187
10-16-2004, 05:48 PM
So you are telling us that less effective port radiating area would not be a big deal.....?

You ever competed before?****, you beat me!:up2somet:

more port area=louder resulting in longer lengths in ports.

mrray13
10-16-2004, 06:02 PM
using ur external dimensions....(i really need the actual model number of ur subs to figur sub displacement) i grabbed some mtx subs T384, put three in the box, tuned it to 35 hz and got a port length of 11.5x1.75x18.5...with a final net displacement of 2.20ft^3..of course, that's assuming 3/4" mdf as well...

larger ports are generally louder and longer for same tuning as a smaller port.....that's why spl boxes have huge ports..but they aren't real deep(higher tuning=louder) but they usually sound like ***....







wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeee :peace:

BASS OUTLAW
10-16-2004, 06:04 PM
the thing is more port area means more port lenght , :( crap i hate port lenght)

jellyfish420
10-16-2004, 10:23 PM
how much is too much port area? is there such a thing?

DBfan187
10-16-2004, 10:26 PM
how much is too much port area? is there such a thing?
I wouldn't go any bigger than your cone area.

OLD_SCHOOL
10-16-2004, 10:56 PM
some people say 200% of the SD . port area great effects SPL.... to small a port @ given power can cause compresion of air passing through port thus changing the tuning and output. (very over simplified answer)

Jonahdude
10-18-2004, 01:53 PM
So, what would be the best port for me to make, to increase my SPL over sealed without losing SQ?

HAVINGFUN
10-27-2004, 03:56 PM
This is a great question that I have never really heard answered. I am like this guy and want SQ out of a ported box. I have a 12inch RE SE in 2.25 cubes tuned to 26hz with 500 watts rms on it with two 3 inch diam. pvc ports that are 23 inches long. If I increase to 4 inch ports they would have to be 40 something inches long per port. So with 3 inch ports am I going to have compressed that makes my ported box like a sealed box with holes etc.