Adding Polyfill to port
well it shouldn't be a fight..
But as far as this thread goes my bottom line is that adding fill to a box or to a port adjusts the Q of the system... (and the effects are well established)
A port's tuning is based on its physical length and that can only be adjusted by changing its length....... adding fill can only change the Q and as the graph I posted so eliquently points out we can only change bandwidth from the port.......
It should also be considered that stuffing a port will have the opposite effect to lower tuning..... and anyone who has ever shoved a T-shirt into a port can probably tell you that......
But as far as this thread goes my bottom line is that adding fill to a box or to a port adjusts the Q of the system... (and the effects are well established)
A port's tuning is based on its physical length and that can only be adjusted by changing its length....... adding fill can only change the Q and as the graph I posted so eliquently points out we can only change bandwidth from the port.......
It should also be considered that stuffing a port will have the opposite effect to lower tuning..... and anyone who has ever shoved a T-shirt into a port can probably tell you that......
Last edited by Haunz; Feb 28, 2007 at 05:08 PM.
ok so I can tell from the warning I just got my previous words were a little harsh.... sorry dukk I don't think you are retarded...
but you might want to review the facts before you say I am 'speculating'
but you might want to review the facts before you say I am 'speculating'
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To be clear to all - I never warned Haunz. We have been on different sides of the coin before. I was right then too 
lol
I disagree that altering the density inside the vent only changes the Q. It changes F1 in your chart. Specifically, it will move it to the left (lower tuning) until you reach a certain density, and then it will shift back to the right, past the original tuning.
lolI disagree that altering the density inside the vent only changes the Q. It changes F1 in your chart. Specifically, it will move it to the left (lower tuning) until you reach a certain density, and then it will shift back to the right, past the original tuning.
dukk your stance is as backwords as your refusal to acknoledge that subs in parallel come with trade offs just like they do in series..
At anyrate your theory seems to be based on the idea that you can adjust tuning by slowing port velocity, I assume so the wave takes longer to travil the port... but that is completely counter intuitive.. port velocity has nothing to with tuning, but relative amplitude only, and attenuating the velocity will only alter the Q factor of the port (which cannot change the center tuning frequency)
to make a port of given length seem longer you would have to slow wave propagation...
the graph I posted came out of a text on accoustic resonance which discusses instrument tuning... agree or not it dosen't really matter to me but that is my argument and Ill stand by it....
At anyrate your theory seems to be based on the idea that you can adjust tuning by slowing port velocity, I assume so the wave takes longer to travil the port... but that is completely counter intuitive.. port velocity has nothing to with tuning, but relative amplitude only, and attenuating the velocity will only alter the Q factor of the port (which cannot change the center tuning frequency)
to make a port of given length seem longer you would have to slow wave propagation...
the graph I posted came out of a text on accoustic resonance which discusses instrument tuning... agree or not it dosen't really matter to me but that is my argument and Ill stand by it....
Last edited by Haunz; Feb 28, 2007 at 05:10 PM.
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lol - series wiring is BAD and parallel wiring is good (relatively)
I hesitate saying "my theory" since really it is reality, but... My 'theory' is not centered on port velocity and the altering thereof... Port velocity doesn't have anything to do with tuning (well for the purpose of this discussion anyway - at some point it does
)
Hey good for you - education is important! I took all that 10 years ago when I was doing my engineering. Integral Calculus isn't so bad 
You'll find that some of it is useful but most of it is just an exercise in learning and conceptualization.
And re your graph - my cat food comment came from Ralph on The Simpsons.
I hesitate saying "my theory" since really it is reality, but... My 'theory' is not centered on port velocity and the altering thereof... Port velocity doesn't have anything to do with tuning (well for the purpose of this discussion anyway - at some point it does
)
lastly Ill add since you seem to infer that I am some kind of physics n00b that I've spent the last several days writting a paper on quantum mechanics and string theory..... and to me this topic to that is like comparing addition to integral calculus....
You'll find that some of it is useful but most of it is just an exercise in learning and conceptualization.And re your graph - my cat food comment came from Ralph on The Simpsons.
