ported box calculations

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=117086
Printed Date: May 11, 2025 at 6:48 PM

Topic: ported box calculations

Posted By: no_joke_chevy
Subject: ported box calculations
Date Posted: October 19, 2009 at 3:09 PM

hey guys like the title said i need help asap. im trying to build a ported box by thursday. i know how to build a box i've built a couple the problem is that i built all sealed and now i have to build a ported one for some one and its been so long i forgot how to do the calculations, i learned how to do it by hand and i dont know how to do the whole calculator thing ive tried and got more confused below is all the info i have on the subs and i can't figure out the min. port dia, how long port has to be one said 245 inches...wow cant figure any of this out..just lost can u please help one last thing what does ported COMPACT 1.5@35 OPTIMAL 2.0@33HZ

TRUNK SPACE

42" WIDE, 15" HEIGHT,ROUGHLY 10 OVER THE HUMP ... BOX IS GONNA BE SHAPED LIKE THIS CAUSE OF HUMP

posted_image

re audio sx 12"

12"
Mounting Depth - 6.9"
Mounting Hole Diameter - 11.2"
Overall Diameter - 12.5"
Bolt Hole Circle - 11.75"
Motor Width - 7.3"
Motor Depth - 3.44"
Basket Depth - 3.46"
Displacement - 0.16 cu. ft.
Weight - 24.5 lbs.

Electrical Q Value -Qes: 0.32
Mechanical Q Value -Qms: 4.4
Total Speaker Q Value -Qts: 0.30
Free Air Resonance -Fs: 30.6 Hz
Equivalent Compliance -Vas: 47.6 liters
One-Way, Linear Excursion -Xmax: 22 mm
Efficiency -SPL 1W/1m: 88.1 dB SPL
Effective Piston Area -Sd: 480 cm^2
DC Resistance -Re: 1.9 ohm
Nominal Impedance -Znom: Dual 2/4 ohm
Thermal Power Handling -Pe: 1000 W
Force Factor -Bl: 21

ported 1.5@35Hz 2.0@33Hz

Replies:

Posted By: no_joke_chevy
Date Posted: October 19, 2009 at 3:11 PM

the title before i posted it said i need help with a box asap

Posted By: DYohn
Date Posted: October 19, 2009 at 6:10 PM

Using sentences makes a post much easier to read. Please read the forum rules and write in regular sentences. What is it you're trying to calculate, the internal volume of your proposed enclosure?

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Posted By: madspeed
Date Posted: October 23, 2009 at 10:35 PM

DYohn] wrote:

sing sentences makes a post much easier to read. Please read the forum rules and write in regular sentences. What is it you're trying to calculate, the internal volume of your proposed enclosure?

Really? I think its pretty clear hes trying to figure out the port dimensions. Sorry that some of us are uneducated (like myself)

Posted By: whiterob
Date Posted: October 24, 2009 at 12:18 AM

There is a slot port and a round port calculator on this site. You can use those instead of doing the calculations by hand. You could also download WinISD for free and use that.

The compact enclosure size is going to be the smallest enclosure that RE would recommend. The optimum is what they believe is going to be best for that sub.

Posted By: mrdond
Date Posted: October 24, 2009 at 2:27 PM

Go to RE audio's website... There is a box building page specifically for their subwoofers.

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Be original yet acceptable.

Posted By: DYohn
Date Posted: October 24, 2009 at 2:40 PM

madspeed wrote:

DYohn] wrote:

sing sentences makes a post much easier to read. Please read the forum rules and write in regular sentences. What is it you're trying to calculate, the internal volume of your proposed enclosure?

Really? I think its pretty clear hes trying to figure out the port dimensions. Sorry that some of us are uneducated (like myself)

Really. You should probably read the forum rules too.

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