ported sub box given,what is it tuned to?

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=110890
Printed Date: May 17, 2024 at 7:12 AM

Topic: ported sub box given,what is it tuned to?

Posted By: samsizzle
Subject: ported sub box given,what is it tuned to?
Date Posted: January 22, 2009 at 2:13 AM

here is the box i was given, it was holding my brothers torn DD 9500 series

posted_image

what do you think it is tuned to? and is it sufficient for my type x running 1000 watts rms, or is it too big?

thanks.

Replies:

Posted By: i am an idiot
Date Posted: January 22, 2009 at 6:33 AM

According to my calculations, it is tuned to about 38 Hz. But of course since I had NO INFO at all to plug into my calculator, I really doubt that it gave an accurate answer.

Posted By: j.reed
Date Posted: January 22, 2009 at 8:20 AM

It would help it you gave measurements to the box and port. posted_image

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Posted By: aznboi3644
Date Posted: January 22, 2009 at 1:34 PM

external dimensions and internal dimensions of the port...looks to be 3/4" MDF.

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Custom Enclosure Design

Posted By: samsizzle
Date Posted: January 22, 2009 at 11:14 PM

okay i tried to be specific as possible, ask if you have any questions or get confused.

thanks!

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Posted By: i am an idiot
Date Posted: January 23, 2009 at 5:57 AM

If the box is 16 inches tall. The inside board of the port can not be 16 inches too. Measure to the end of the port board that is nearest the speaker.

Posted By: j.reed
Date Posted: January 23, 2009 at 9:29 AM

Ok so i pluged in the 28W x 14H x 16D with 3/4 MDF. That gave me 2.78 Cubic foot. I then subtracted the port area. 3W x 12.5H x 14D that was .30 cubic foot from the airspace. Then i subtracted the displacement of the 12 in sub according to the DD web site is 0.1946 cubic foot from that giving me. 2.29 cubic foot for the total internal airspace rounding to the nearest hundreth. Then using the slot port calculator on the site. Im getting a FB of 48Hz ='s the 14 inch port length. This seems quite high for me. Does anyone have a box builder program to compair the numbers with mine?

Im coming up with 48 Hz tune. Granted this is assuming there is not internal bracing that would cut down the airspace any further than what i have figured.

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Posted By: haemphyst
Date Posted: January 23, 2009 at 9:29 AM

port is 14 inches deep...

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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."

Posted By: j.reed
Date Posted: January 23, 2009 at 9:47 AM

I just pluged in the spec off my L7 box and the numbers are not coming out correct. I used full airspace and every combo of port and driver displacement Added and subtracted to see if i could match it to what the engineers at Kicker gave me. The numbers are not matching up. I know my port is FB of 33hz and it peaks at 48Hz. Which is what the Engineer said, was graphed at and i have done a lot of testing on TL. My loudest tone is at 48hz just like they say. But when pluggin into the slot port calculator It is showing the FB higher. Which leads me to belive the port calculator is off.

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Posted By: j.reed
Date Posted: January 23, 2009 at 9:49 AM

haemphyst wrote:

port is 14 inches deep...

that what im getting from his sketch up. Says port about 14" deep.

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Posted By: haemphyst
Date Posted: January 23, 2009 at 7:44 PM

That computes pretty close to what I came up with in JBL SpeakerShop, too... I have one word for an enclosure tuned that high: GAH! That's a woofer, not a sub, and likely a one note wonder, as well!

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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."

Posted By: samsizzle
Date Posted: January 24, 2009 at 2:49 AM

haemphyst wrote:

That computes pretty close to what I came up with in JBL SpeakerShop, too... I have one word for an enclosure tuned that high: GAH! That's a woofer, not a sub, and likely a one note wonder, as well!

so is this box sufficient for my type x or too big? am I hurting it?

I appreciate all the help guys :)