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enclosure resonance

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=77392
Printed Date: April 30, 2024 at 9:37 PM


Topic: enclosure resonance

Posted By: jackaroo_88
Subject: enclosure resonance
Date Posted: May 07, 2006 at 4:45 AM

hi,
I am having a bit of trouble finding methods to calculate the enclosure resonance. It is the Fb parameter on the port calculator page. Are there any text book ways of calculating this for my home-built box? any help would be much appreciated.
thanks
jack



Replies:

Posted By: hardknocks
Date Posted: May 07, 2006 at 8:18 AM
this is where you would want ur box tuned at, lets say you are looking for 35 hz then enter 35 as ur vb

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4-15" RF T2
6-7" RF Component sets
8 Planet Audio 900d
10 Batcap800
1 250 amp alt
1 300 amp alt
2" sound deadner roof,doors,floors




Posted By: jackaroo_88
Date Posted: May 07, 2006 at 8:35 AM

ok, so how do you know what frequency you want it to be tund to, isnt there a calculated frequency for the box? if so how do you calculate it?

thanks





Posted By: stevdart
Date Posted: May 07, 2006 at 8:49 AM

Find the frequency to tune a vented box according to:

  • the recommendations from the manufacturer for that particular sub
  • your musical tastes, e.g. SQ or SPL?

In general terms, box tuning is calculated from two things:  box air volume and port volume.  Port volume is determined by port opening area X port length.  The application on this site figures port length for round ports.

I must tell you this right from the start:  building and tuning a vented box is not for the amateur.  By the time you understand exactly what you are doing you will no longer qualify as amateur status, which is the good part.  Here's where you should start.

You will see actual calculations and theory here.  Then you can use this knowledge to better understand the port calculators that are available.  Here is one that provides graphs according to your input:

Other more advanced and more accurate methods would be to use one of some available box-building programs.  WinISD Pro is a popular one that a lot of people use.  Refer to the sticky subject above on this forum for links and as a starter guide.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: jackaroo_88
Date Posted: May 07, 2006 at 10:25 AM

thank you for the post, it has helped a lot.

with the musical tastes, wht is SQ and SPL?

and also, im using the Fb frequency to calculate the required port length that i need using the calculators on this website, so how can i know the port volume if it is opening x length?

thanks





Posted By: Aruman
Date Posted: May 07, 2006 at 12:15 PM
SQ= Sound Quality.
SPL= Sound Pressure Level,how loud your sound system is, measured in dB(decibel)

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Shaking The Neighborhood





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