Confused by ported box specs
Thread Starter
On The Tree
Joined: Aug 2005
Posts: 106
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Confused by ported box specs Ok, I have one JL12W3V2 that I'm going to be building a ported box for. I have the dimensions from JL's instruction booklet with a recommendation for the port to be tuned to 30.8 Hz. I'm confused by this idea of a "tuned port". Does it mean if the port is tuned to 30.8 Hz and what would it change if I tuned the port higher than 30.8? Also.. I have a subsonic filter on my Alpine amp that is set for 30Hz... what will this change if anything?
TECH Enthusiast
Joined: Nov 2004
Posts: 600
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From: Coppell,TX
you tune a box so that the speaker/box combo will be most effecient at that frequency. What was most likely reccomened was where the sub/box combo will make the flattest db vs frequency curve. Download WinISD, it can show you alil better on how tuned boxes work. http://www.linearteam.org/winisd.html
TECH Senior Member
Joined: Apr 2004
Posts: 6,157
Likes: 1
From: Texas
30.8hz is the -3db roll off which means that once you get to that frequency (and lower) you will rapidly lose your frequency response. 30.8hz is a great roll off because most bass notes are around 40+. I wouldn’t try to change that frequency.
In this graph, the red curve will show you a -3db roll off at around 22 Hz.
After this point it the response of the box dramatically diminishes.
In this graph, the red curve will show you a -3db roll off at around 22 Hz.
After this point it the response of the box dramatically diminishes.
