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porting a box

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=104772
Printed Date: April 20, 2024 at 3:34 AM


Topic: porting a box

Posted By: cody2white
Subject: porting a box
Date Posted: May 16, 2008 at 1:35 AM

hey guys, i decided to build a ported box for my 2 12 alpine x's. i have winisd and i understand it, i just dont get what frequence to tune it at or making the response flat. why do i want it flat as possible? wouldnt i want the extra 3db at 38hz or something? i dont get it well any info will help thanks

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Replies:

Posted By: sedate
Date Posted: May 16, 2008 at 1:45 AM

Its not really going to be "flat" per se - it'll still be a curve.

Personnally, I define "flat" as +/- 3db from 30 - 80hz.

So from 30hz up to 80hz, the frequency should stay within 3 db at the same input power.  Make sense?

I would start your tune @ about 33hz and see what that looks like.  Box size should be ~2.75 - 4cft.  Bigger is almost always better - but ur vehicle and how much weight you want to add are important considerations.



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"I'm finished!" - Daniel Plainview




Posted By: aznboi3644
Date Posted: May 16, 2008 at 2:26 AM
flat on WinISD won't be flat in-vehicle response with eq'ing. Transfer function/ cabin gain




Posted By: DYohn
Date Posted: May 16, 2008 at 10:00 AM
Plus, one of the beauties of using a program like WinISD is if you want or need +3db @ 38Hz, you can design an enclosure that will give you that.

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Posted By: cody2white
Date Posted: May 16, 2008 at 2:53 PM
ohhh i get it, haha thanks guys! when you guys talk about eq do you mean use something like this? would something like this help?

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Posted By: sedate
Date Posted: May 16, 2008 at 4:09 PM

No.  That's a line driver - it amplifies your pre-amp frequencies if for some reason your head unit can't get ur amp to full output. 

They really aren't that useful unless you like injecting lots of bass into things that don't have alot of it.  Audiophiles tend to shun them.

I think these guys make the best EQ's and xovers on the market:

https://www.mobileaudiocontrol.com/



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"I'm finished!" - Daniel Plainview




Posted By: tubbs04
Date Posted: May 16, 2008 at 6:27 PM
I just bought an audiocontrol 4xs! It's a pretty neat little machine!

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...don't crush the weasel...




Posted By: cody2white
Date Posted: May 18, 2008 at 9:11 PM
hmm. i still bought it anyway haha i wanna see how it will sound and what makes it tick. i have a really noob question but i need some help. what is the best way to attach fleece to a project. i herd start from the middle ( the subs ring) and work your way around or  i herd left to right. i tried the left to right and failed miserably. it keeps wanting to overlap each other, how do the professionals do it?

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Posted By: haemphyst
Date Posted: May 19, 2008 at 9:37 AM
<dave shakes his head in utter disgust and unbelieving sadness>

I cannot believe what has happened to Soundstream. What was once one of the finest manufacturers of audio gear for the car, (bar VERY few) is now flea-market... Anybody ELSE remember the "Class A 50"? You'd've NEVER bought one of those from "SonicElectronx". That linked piece looks like something STRAIGHT from the swap-meet. What a chunk of... well, let's just say we can safely label it a "splashlog". (As in - FLUSH IT!)

So few truly good car audio companies, anymore...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."





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