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Sealed box questions

Old 09-28-2011, 04:08 PM

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Sealed box questions

Some of you may not believe it, but I haven't built a sealed box in about 5 years.

I'm thinking about doing it for once in my car and I have some questions regarding it.

1: coming from a home audio background I've always been taught that you should try not to have any parralel sides for standing waves etc. Any truth to this?

2: QTC is ideal at .707 for the flattest response. correct?

3: Polyfill. Just test with it after the enclosure is done?

4: Flush mount the sub to help with sound waves?

And DUKK, no need to start with the "why sealed?". lol
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Old 09-29-2011, 02:42 PM
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HEY! did I say anything??

1) Not really but it doesn't hurt to use baffles or damping on the walls to kill upper range reflections.

2) Qtc = .707 is the best balance of size and response. Lower Qtc can extend bottom end but the box gets bigger. Higher Qtc increases response, decreases bottom end, and shrinks box size.

3) I always try to have some sort of damping in the box.

4) Unnecessary. Much more important with mids/tweets but usually impractical in a car anyway.

For sure though, the best way to make sure that your sealed box is going to sound good is to put a port in it.
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Old 09-29-2011, 10:04 PM
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The subwoofer will be a more determining factor as to weather of not it will sound good in a sealed box. Port a woofer designed for a sealed box and typically you will get a large response peak, and seal a woofer optimized in a ported box and you will have a great mid bass, as a general rules of thumb but by no means gospel is at qtc of .4 and lower generally a ported box will sound better, between .4 and .5 is the grey area lots of woofers fall into and above that a sealed box will usually sound better. All the comments you stated ring true in most circumstances
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Old 10-02-2011, 01:27 PM

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It'll be a 10W3V3, which if im not mistaken likes sealed.
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Old 10-02-2011, 09:31 PM
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one thing to remember is that for car audio, lower -3db frequency is going to be much higher, about 50Hz, than for a home sub, which you want under 30Hz. The reason is called "room gain", which can be around 50hz in a car too.. That provides a bass boost to counteract the slope of the sub in box.
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Old 10-15-2011, 12:59 PM
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Originally Posted by wasted911 View Post
It'll be a 10W3V3, which if im not mistaken likes sealed.
Not sure if I should post this here, but having issues getting an answer elsewhere.
I just bought a 12" Kicker CVX and having same sealed box issues trying to get the best SQ, power and size for the sub. I would like to go ported, but in search of the perfect box for a flatter response, sealed is just easier, and cheaper

here's the manual:

I ordered a 1.0 cu ft box and a solo classic, which is designed for 1.0 cu ft, but the sub order fell through, so I'm stuck with this box for now. The manual for the CVX says 1-4.6
Also the rms power fluctuates quite a bit between the 2 sizes. I'm running an MB Quart Onxy with 500w @ 4 ohm. Saying it does 600 rms, what would the perfect sized box be to hit all range of notes and pushing the sub right to its technical limits?
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Old 10-17-2011, 05:14 PM
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^^open a new thread bro...I'll post some winisd graphs for you...this is another guys thread.

Last edited by Denonite; 10-17-2011 at 05:19 PM.
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