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how much output am i losing?

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=118691
Printed Date: May 15, 2024 at 1:18 PM


Topic: how much output am i losing?

Posted By: armymp90099
Subject: how much output am i losing?
Date Posted: December 20, 2009 at 8:33 PM

Ok I build my current box before I learned about port area for a certain box. My box currently is 3.2 FT^3 NET and it only has (1) 4" Flared port. So apparently I am WAY off. How much output am I losing by this limited port area? Im running 1K RMS of clean power daily. Would it be worth it to rebuild the box with more port area? Would it make a difference? Thanks guys.

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-ETS-
Escape The Scilence



Replies:

Posted By: j.reed
Date Posted: December 20, 2009 at 9:02 PM
What sub? If you are using the DC lvl 4 xl you were talking about in your other post. Not having enough port area will greatly hinder that subs output. Having a 4" port is almost like running it in a sealed enclosure. They are not designed for sealed and it will lose a lot of output.

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Posted By: armymp90099
Date Posted: December 20, 2009 at 9:15 PM
lol no i dont have enough money for that yet im still running the alpine Type R 15 with the MRP1000.

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-ETS-
Escape The Scilence




Posted By: j.reed
Date Posted: December 20, 2009 at 9:33 PM
for that cubic foot you need double the port area and your enclosure is a bit large. Im positive you would see a good increase of output in a correct enclosure, as well as better sound.
Type R info.

Middle of page 4 is all the enclosure specs, port specs and everything else you need to know to make a correct enclosure for the sub. If you have any questions feel free to ask.

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Posted By: armymp90099
Date Posted: December 20, 2009 at 10:39 PM
yeah ive looked and looked and called the engineers at alpine to get their reccomendation. lol I just cant seem to get a good box design for my car with small volume and still be effective. I need a wide shallow box for the best daily output in my car and ive tried multiple designs. I was going to modify the box i showed you before to work for the type r and tune it to something not sure yet though. Would you think 2.25 or 2 cubes would work best? Im still new to box design and Id like to learn everything I can. lol

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-ETS-
Escape The Scilence




Posted By: j.reed
Date Posted: December 20, 2009 at 11:43 PM
I would do the 2.9cu.ft. Gross. 22.5sq.in port area and 27 inches long.

Gross is total volume with port and driver displacement already taken into account. Makes it very easy. Just use the site calculator to see what measurement best fit your space to get you 2.9cu.ft. Then figure a port opening that will work. L x W =ing 22.5sq.in. or as close as possible. then make it 27 inches long.

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Posted By: armymp90099
Date Posted: December 21, 2009 at 12:25 PM
ok ive been punching numbers and if they tuned the port to 30hz that would give me 27 in port length roughly...this seems a little low to me. what do you think?

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-ETS-
Escape The Scilence




Posted By: j.reed
Date Posted: December 21, 2009 at 7:07 PM
That should be a really good musical tune for that sub. More of an SQ tune. If your wanting a bit more loudness at a bit of sacrifice to a more true SQ sound up the tune to about 33hz. so 22.5cu.in. port area, port length 21" Gross volume 2.82cu.ft.

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