> if you read my original message I stated that from my experience, as long 
 > as 
 > the port's opening size and port lenght remains the same, the shape can be 
 > manipulated.
       As long as the opening size from either end is consistent and 
remains so throughout the cylinder/port than it may be "redirected" to match 
up with a desired opening in the vehicle. But to change diameter at any point 
along the cylinder would negate "tuning". It would then become a "port" not a 
"tuned port". 
 > JA>         Port placement is also extremely important. Too close to an 
 > interna
 > JA> speaker wall and the port looses efficiency and tuning. Set centered 
on 
 > the
 > JA> box causes a boomy, "goofy" sound that is very inaccurate and just as 
 > although I am into car audio I have never seen this effect.. 
 > at work we have a standard size of box that we sell quite a few of, and we 
 > place the ports depending on where they would best suit the customer's 
car, 
 > and I've never noted a change in sound quality or "goofy" sound..
       Absolutely. If you get a return or box you can experiment with, seal 
up 
the ports. Place like ports immediately next to internal walls and measure 
the 
response. You will find a big drop in the frequencies you are expecting. 
Likewise, placed in the dead center of the box you will find what I can only 
describe as a raspy response compared to a very smooth, mellow response if 
placed off-center.
       I cannot offer you a definitive, scientific reason why these responses 
are so, for I too am not a professional sound engineer and am learning as I 
go. Perhaps you could offer some suggestions from your experience. I can only 
suppose that in the case of the tuned port placed near a wall, the reaction 
of 
the moving air to the wall reduces its' effect on the port. That seems easy 
enough to reason through. But for as long as I have been building speakers, I 
have yet to figure out why the exact center placement has had such a strange 
effect on the response of the port. You would think just the opposite. But 
then again, you get the same reaction to loudspeakers placement in a box: 
ff-
center is fine.....Dead-center is a harsh, roughened response.
Cheers, John
--- AdeptXBBS v1.07f (Registered)
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