ported 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=121566
Printed Date: April 29, 2024 at 11:17 PM

Topic: ported box

Posted By: spmpdr
Subject: ported box
Date Posted: April 28, 2010 at 9:26 AM

I just got my box back from the shop it looks great ,however i double there math to make sure and i cant figure out what the box is tuned to.Heres the specs:
2.75-2.80cu.ft slot port enclosure
port width:3.75"

port height:15"

port depth: 17" (the port goes into the box about9" then goes at right angles for another 8"

What is this box tuned to? How did you figure it out ,I tried a slot port calculator but the math didnt seem right.Also the box is just a tad small for my subs (.2cuft) how will this affect sound and should I add pillow stuffing to the box?

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-A vision without a plan is just a hallucination-

Replies:

Posted By: DYohn
Date Posted: April 28, 2010 at 1:17 PM

Assuming the 2.75 cuft is net internal volume, your slot is tuned to about 48Hz.

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Posted By: spmpdr
Date Posted: April 28, 2010 at 2:15 PM

DYohn] wrote:

Assuming the 2.75 cuft is net internal volume, your slot is tuned to about 48Hz.

Thanks as always for the info,DYohn. That is the net internal volume.The subs im using called for 3.0 cubes tuned to 33hz(re audio sr 12's 4ohm dvc)but do to size restrictions in my truck this is the max we could figure put @ 48hz do you think they will sound good?

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-A vision without a plan is just a hallucination-

Posted By: DYohn
Date Posted: April 28, 2010 at 3:18 PM

It might sound OK. Should get pretty loud, might be boomy. You'll prob need a subsonic filter set to about 40-45Hz depending on how powerful an amp you use.

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Posted By: spmpdr
Date Posted: April 28, 2010 at 4:47 PM

DYohn] wrote:

It might sound OK. Should get pretty loud, might be boomy. You'll prob need a subsonic filter set to about 40-45Hz depending on how powerful an amp you use.

The amp im using is an re audio 1600.2 v2 that does 800watts rms@4ohms ,I thought that it might be a little boomy as well ,in the past with ported boxes i have added pillow stuffing to slow down the air movement and that has taken out alot of the boom.I hope it will do the same on this install.

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-A vision without a plan is just a hallucination-

Posted By: j.reed
Date Posted: April 28, 2010 at 7:15 PM

So you know for future reference. The site slot and round port calculators work off the NET volume. So simply measure your total enclosure with the enclosure calculator and material thickness to find the GROSS internal volume. Then figure out the port volume including walls of port, any additional bracing volume and driver displacement. Subtract them from the GROSS. That will be your NET volume. Now you can plug that into the port calculator with your port opening and length to figure the FB of the enclosure. As for measuring length of a folded port. You will take the measurement down the center of the port. Hope this helps. See what you come up with and if needed i or someone else can double check your findings.

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