2000SPL Box Design

[SSS 18734 5,000+ posts]

use the rear port air velocity window, when changing port width and length and try to stay as close to the 17m/s or below as you can, since any thing above that speed makes port noise and also keep an eye at the freq that the peak of the curve is on, since that the freq when youre actually going to hear the port noise. if the freq is high then dont worry about it and if its below a freq youre sure youre never going to play on like 25hz or for sure 20hz and below then dont worry about it ether.also, on the signal tab make sure you put on there the rms power youre going to be giving the particular sub or subs youre designing the box for since that will change how fast the air goes in and out off the port.

holy moses that helps a ton. I checked out my plans and the graph was off the chart, at like 170. But I cant seem to keep the air velocity below about 60 with the box that im planning on...

best I came up with was

2.00 cu.ft. airspace

tuned to 35hz

a single 4" wide port, 10" tall, 40" long.

at tuning, I have an air velocity of 58 m/s...but thats about 3x less velocity than my current box... which doesnt have all that much noise and peaked at 190 m/s.

Should I be concerned with the 40" length?

 

[PowerNaudio 10+ year member]

port length

the only problem is see with a 40" long port is being able to fit in the box, as long as you have tuned it right and port noise is under control if you can find a way to fit 40", lol , go for it.

you can always have the port out side the box.

at tuning, I have an air velocity of 58 m/s...but that's about 3x less velocity than my current box... which doesn't have all that much noise and peaked at 190 m/s.

check at what frequency is peaking at if its has a peak of 190 @ 90hz or 28hz and you don't usually play at those frequencies then its wont be a problem.

 

[SSS 18734 5,000+ posts]

check at what frequency is peaking at if its has a peak of 190 @ 90hz or 28hz and you don't usually play at those frequencies then its wont be a problem.

maximum air velocity was at its tuning frequency, approx 48hz.

With the new box, the velocity is highest at 32hz, at around 58 m/s.

 

[PowerNaudio 10+ year member]

maximum air velocity was at its tuning frequency, approx 48hz.
With the new box, the velocity is highest at 32hz, at around 58 m/s.

190m/s @ 48hz and you say the noise was minimal.

most likely the bass was drowning it from being super noticeable.

on one of my experimental boxes i stuck a 2" port 10" long tuned at 31hz or 32hz box was 1.12cu ft. for a 12" sub pushing it with a 300wrms amp, the port noise would peak at 65.9m/s at 25hz and i could hear port noise from like the 50hz~55hz down, gradually louder till like high 20s where all you could hear was port noise. lol.

i guess the position of the port in relation to driver will play a big factor in, if you hear it or not.

is the sub louder then the port noise and things, but if there is port noise then the port is just too small.

 

[bigbangtheory 5,000+ posts]

Man after reading that I think I will stick to a sealed box for my 3004spls for now. It will be to complicated and to much money for a ported box. Glad I read this.

 

[Spkrman]

4 cubic feet is way too large. im putting two of these in my trunk, and those subs arent well-suited for large boxes. They reach excursion really quickly.

actually a larger box will decrease excursion to a point, until you get TOO big.

Whats the breaking point? Gotta build and test //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

winisd means poop, just because it looks like that on paper doesn't mean its going to respond like that! Very littl of what actually effects response is taken into account with ISD.

 

[FOSGATE JOE 10+ year member]

so true ^^^^^^^%#!