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Anyone Use Qtc In Enclosure 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=18149
Printed Date: May 05, 2024 at 9:11 AM


Topic: Anyone Use Qtc In Enclosure Calculations

Posted By: IronCy
Subject: Anyone Use Qtc In Enclosure Calculations
Date Posted: August 27, 2003 at 8:25 AM

Hey I was wondering if anyone takes Qtc into consideration when calculating enclosure volume....I understand that the lower the Qtc, the more volume required......ideal is .707, average is .8-1.  Just wondering if anyone concerns themselves with this.

Thanks

-Cy




Replies:

Posted By: DYohn
Date Posted: August 27, 2003 at 12:27 PM
Qtc is relevant when designing acoustic suspension (sealed) enclosures.  This page explains it a lot better than I could.  Cheers!




Posted By: IronCy
Date Posted: August 27, 2003 at 12:58 PM

i understand what Qtc is, I was just wondering if anyone else takes it into consideration, and what Qtc value they use when calculating sealed enclosure volume.

-Cy





Posted By: wizzle
Date Posted: August 28, 2003 at 2:10 AM
do you know what kind of response curve you are going for?  it is not used in the actual design of the box, but rather the design of the sound you are going for.  we use it here, but not on every box.t some of the other shops i worked for in the past use it all the time.  by the way .707 is the ideal qtc for home applications, so it may not work well in cars. a little bit higher will help in vehicles.  this is to help overcome the natural noise floor of the vehicle.  around .9 if i remember what i read correctly.  this is definitly an important factor to take into consideration.




Posted By: IronCy
Date Posted: August 28, 2003 at 5:40 AM

As Qtc goes up, volume requirements goes down...for my specific speaker, a Qtc of .707, given the subs' thiele parameters, it would call for 3.5 cuft....as  I raise it to .9, the volume requirement falls to 1.8cuft---including a 10% increase in volume and compensation for the volume of the woofer......but I also know that some mtx subs call for a Qtc of 1,.25.....so at this point I wondering what I should shoot for..........wizzle, what is the most often used at your shop......when trying to acheive spl, and thanks for your reply.

-Cy






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