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View Full Version : Numbers are weird or I'm retarded.



soldiermedic
04-26-2009, 12:02 AM
Win ISD gave me some numbers on a ported box, but I don't understand how the port length is so high...got a vent length of 102.62 in. How does that work? I'm new at this...How do I read this?

gotparts90
04-26-2009, 12:07 AM
what size port? 12 inch? change the port size see what happens

thegreatestpenn
04-26-2009, 12:11 AM
you must've used the wrong units somewhere. recheck your units of measurement

soldiermedic
04-26-2009, 12:15 AM
Port is 3 inch by 11.5 inch. When I decrease the vent diameter, the required port length decreases, which makes no sense to me...unless I am reading things wrong.

soldiermedic
04-26-2009, 12:38 AM
I redid the port measurements...the original ones were the speaker manufacturers specs. A little editing, I got .7 cubic ft box, 1.5x12" port with 53.83 inches in length. Why is it when I make the port narrower, the length gets shorter?

lilmaniac2
04-26-2009, 12:40 AM
because the lower sq in of port area, the shorter port you need for the same tuning, its basic box design

ps a .7 cubic ft PORTED box is tiny, i hope its for an 8 or somethin, and even then thats too small

soldiermedic
04-26-2009, 12:49 AM
It's for a 10, but I am looking to create a flatter response. when I increase the box size, I get a huge discrepancy with a difference of 6 db's both ways at whatever frequency I set it at. But when I decreased the size of the box, I got the balance back. I know this makes the box abnormally small for a ported box, but I am willing to risk it unless someone can talk me out of it.

lilmaniac2
04-26-2009, 12:50 AM
P.S. winISD models never EVER duplicate real world results in a vehicle

DNick454
04-26-2009, 12:54 AM
It's for a 10, but I am looking to create a flatter response. when I increase the box size, I get a huge discrepancy with a difference of 6 db's both ways at whatever frequency I set it at. But when I decreased the size of the box, I got the balance back. I know this makes the box abnormally small for a ported box, but I am willing to risk it unless someone can talk me out of it.


If you want a flat response, you want a larger, ESB style box tuned really low. Smaller boxes are for tuning higher and being boomy at a very specific frequency for SPL purposes. If you want a super flat response, get something like 1.5 cubes with the port volume already subtracted and go for like 25 square inches of port area. For example, a port that is 2 inches wide and 12 inches tall would be 24 sq. in of port area and would be fine for a 10, large enough to not get port noise. Then you make the port longer or shorter length wise to set the tuning. Just use the RE Box calculator if you're going for a simple slot-port design. You can tweak each aspect of the box and it'll even give you a cut-sheet to build the box with.

Best of luck :D

soldiermedic
04-26-2009, 01:00 AM
What is an ESB style box? (noob)

DNick454
04-26-2009, 01:09 AM
What is an ESB style box? (noob)

Sorry, mis-typed that. I meant "EBS".

EBS boxes are purposely built larger and lower tuned than recommended. This makes for a box that doesn't have any extremely high peaks at certain frequencies. It keeps a very even response at most frequencies with really really good low end extension.

These boxes are pretty big though, you've gotta have some space to spare.

If you were originally planning to do like a single 12" in say 1.5-2 cubic feet, and EBS box would be like 2.5 cubic feet tuned under 25 Hz.

soldiermedic
04-26-2009, 01:27 AM
Sorry, mis-typed that. I meant "EBS".

EBS boxes are purposely built larger and lower tuned than recommended. This makes for a box that doesn't have any extremely high peaks at certain frequencies. It keeps a very even response at most frequencies with really really good low end extension.

These boxes are pretty big though, you've gotta have some space to spare.

If you were originally planning to do like a single 12" in say 1.5-2 cubic feet, and EBS box would be like 2.5 cubic feet tuned under 25 Hz.

Thanks, you just clarified 10 hours of looking at my computer in 20 minutes.

SicAudio
04-26-2009, 02:17 AM
so what do you think of BassBoxPro 6 DNick454 ??
ive tried winisd and never had good results.

soldiermedic
04-26-2009, 02:21 AM
so what do you think of BassBoxPro 6 DNick454 ??
ive tried winisd and never had good results.

I've never heard of them, I'll check it out.

DNick454
04-26-2009, 02:09 PM
so what do you think of BassBoxPro 6 DNick454 ??
ive tried winisd and never had good results.

I'd say the easiest, and most accurate, box calc's are the ones offered by RE Audio and the one on www.bcae1.com

The easiest is the RE Audio one, but that only for slot ports. The bcae one you can adjust for all different sizes and dimensions for ports including round ports but you need to know a little more information. The bcae one also can't do curved ports, so you have to do some figuring out on your own there.


EDIT: If you're looking for the one on bcae1.com It can be a bit hard to find, it is a rather large database. There is the main page for viewing, then there is like a little tiny scroll-down page on the right with the directory of information. The one you are looking for with all the box building calculators is number 110. It's a ways down. Good luck :)