General Discussion General discussion about all things car audio, from pioneer, orion, alpine and eclipse.

Qtc vs box size and sub volume rating

Thread Tools
 
Search this Thread
 
Old 02-20-2007, 12:07 PM
  #1  
0 Watt CAFz'r
Thread Starter
 
cat-alac's Avatar
 
Join Date: Feb 2007
Posts: 5
Qtc vs box size and sub volume rating

I bought an Infinity Kappa 102.7 10 for my boat. I am slowly learning some of the variables of sub installs. (Amp is JL E6450, bridged 5&6 channles to 300 watts, 4 ohm)

Thiele parameters for Qtc calculations are:

Vas 1.62ft3, Fs 20.40, Qts 0.45

The manufacturer recommendation for sealed is 0.75 ft3 which yields a Qtc of 0.8 with an F3 of 32.5hz.

My understanding is for flat response ie all Sq you should be Qtc of 0.707.
But for most all around listening you should target 0.9 to 1.1 for a Qtc in a sealed application.

If I plug in the parameters to get Qtc at 0.9 I end up with a box volume of .54 ft3, F3 is 33.84 and if I go to a Qtc of 1.0 I get a volume of 0.411 ft3, F3 is 35.64. These volumes would be great if they work as I need a small volume box.

Question am I correct that I can go to 0.54 ft3 and get a good mix of Sq and Spl with the 0.9 Qtc? Peakdb, or ripple is 0.8db at 0.54ft3.

Or has Infinity made a typo on parameters or on volume recommendation?
cat-alac is offline  
Old 02-20-2007, 12:39 PM
  #2  
50 Watt CAFz'r
 
Keswick R/T's Avatar
 
Join Date: Jan 2007
Posts: 149
chances are with a box that small you would have almost no low end bass.
Keswick R/T is offline  
Old 02-20-2007, 01:35 PM
  #3  
4000 Watt CAFz'r
iTrader: (3)
 
Haunz's Avatar
 
Join Date: Jun 2002
Posts: 4,218
A QTS of .707 is a middle ground between transient response and damping and also gives maximally flat response...

I would recommend going this route unless you have a reason not to and have considered all the trade offs....
Haunz is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
prabhakarglv
Car Audio Technical Discussions
0
03-09-2014 11:55 PM
b34tBoX
Enclosure Design & Construction Help
3
11-16-2012 01:36 AM
jay72228
Car Audio Wanted (WTB)
0
09-13-2011 04:41 PM
TragicMagic
Enclosure Design & Construction Help
1
01-20-2009 07:43 PM
andrewsfm
General Discussion
1
04-13-2007 03:01 PM



Quick Reply: Qtc vs box size and sub volume rating



All times are GMT -5. The time now is 12:46 PM.