it is possible to have the port in the back and sub in front of the box, and just recalculate the tuning to make it work. (take in effect the extra length by having the port on the wrong side, and adjust the length of the port accordingly.)
just my thoughts.
------------------ I respect any sub that can make me pass out.
posted
I think what he means is why do people fire their enclosures (driver and port) at the trunk instead of into the cabin. the reasoning here is that they are trying to increase the distance the wave has to travel, especially in small cars, and allow for the quarter wave (that's what it's called, right?) to be reached. if they can plan it right, it will be louder, because the sound wave is more completely formed. do people just fire it backwards and pray? absolutely. do people fire it backwards because to them it "sounds" louder (but may not be on a meter)? absolutely. do people fire it backwards because it sounds "cleaner" (ie no port noise, and you don't hear the distortion)? absolutely. do people fire it backwards so that it looks cooler when you open the trunk and they are showing off? absolutely! I'm sure there are other reasons.
------------------ Jeff Sony CDX-7850 Sony XDP766-EQ 3 Sony 752-EQX 2 Sony ES 6.5 Seperates 2 Crossfire CFA-1000D (Only 1 for comp) 2 12" HX2s All I want is 150, and I'll be happy
quote:Originally posted by Hertz_so_good: I think what he means is why do people fire their enclosures (driver and port) at the trunk instead of into the cabin. the reasoning here is that they are trying to increase the distance the wave has to travel, especially in small cars, and allow for the quarter wave (that's what it's called, right?) to be reached. if they can plan it right, it will be louder, because the sound wave is more completely formed. do people just fire it backwards and pray? absolutely. do people fire it backwards because to them it "sounds" louder (but may not be on a meter)? absolutely. do people fire it backwards because it sounds "cleaner" (ie no port noise, and you don't hear the distortion)? absolutely. do people fire it backwards so that it looks cooler when you open the trunk and they are showing off? absolutely! I'm sure there are other reasons.
This is NOT what he is saying... He is saying put the port on a different plane and see an increase in SPL. I think it has something to do with cancelation and what Colin was saying in another topic where the waves coming from the port are actually slower than the ones coming from the sub.
posted
could very well be, but hard to know when the questions are so vague. now...did I read that correctly...sound waves coming from the port move more slowly than the sound waves coming from the sub? is that a joke?
------------------ Jeff Sony CDX-7850 Sony XDP766-EQ 3 Sony 752-EQX 2 Sony ES 6.5 Seperates 2 Crossfire CFA-1000D (Only 1 for comp) 2 12" HX2s All I want is 150, and I'll be happy
posted
Sound is sound. It travels at the same speed no matter what freq its at. At least in the same medium under the same conditions. The sound from the port could possibly be delayed or even out of phase with the sound eminated by the woofer itself bu they do NOT travel at different speeds.
Posts: 736 | From: Albertville MN USA | Registered: Mar 2000
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quote:Originally posted by 98hondaf3: This is NOT what he is saying... He is saying put the port on a different plane and see an increase in SPL. I think it has something to do with cancelation and what Colin was saying in another topic where the waves coming from the port are actually slower than the ones coming from the sub.
Andy
I know is sounds strange, but I know I read something along those lines a few weeks ago in this forum. damnit, where is the search function. But then again, maybe I misread it and he was actually talking about cancellation.
posted
Andy, Are you saying that Colin said sound waves in a port travel slower? I find it hard to believe he would say that. If he did, I’m gonna slap him. Sorry Colin
As far as cancellation goes, that is the only reason you should face stuff into a trunk rather than forward. A trunk is just a big leaky lossy flexible enclosure. But it also has the correct dimensions to cause an incredible amount of cancellation. In Fact, Ive read that they are designed this way on purpose to cut road noise down. When sound goes behind a sub, bounces off the rear of the trunk and returns to the sub, it is 180 degrees out of phase (or close to it) and cancels out a lot of the sound.
The correct way to do it is to have everything facing forward and seal off the trunk form the cabin completely. That way you get no cancellation from the trunk, and no losses from the crapiness of the trunk.
------------------ 2-DD 9512's 2-2000X's (for now) 8.0ft^3 box in a civic trunk One big ass port ?????dB's
It's not the size of your woofer, It's the size of the waves your woofer makes!
Posts: 1247 | From: Fullerton. CA ,USA | Registered: Oct 1999
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quote:Originally posted by BEYOND AUDIO: Sorry guys i forgot about this post...
I was wonderign why people have the subs firing upwards in a hatchback and the ports firing backward??????
For smaller ports, higher velocity, I thinks thats the ports firing backwards will help couple the higher pressure change to the air. But if you have a big port and lower velocity, I think you could get the same results facing everything up. All opinion there, no actual experience, just what I know from theory.
------------------ 2-DD 9512's 2-2000X's (for now) 8.0ft^3 box in a civic trunk One big ass port ?????dB's
It's not the size of your woofer, It's the size of the waves your woofer makes!
Posts: 1247 | From: Fullerton. CA ,USA | Registered: Oct 1999
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quote:Originally posted by mr.dank: Andy, Are you saying that Colin said sound waves in a port travel slower? I find it hard to believe he would say that. If he did, I’m gonna slap him. Sorry Colin
I only thought it was him... but then again, I get dilusional quite often
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