slot port question
#11
Not you obv. but I was asking questions like where exactly does the port end (inside a slot port) because of end-corrections, if the port length continues for 1/2 of the port width further than the physical inside port-wall than when you measure from the center-line there's some space left, wouldn't you add it to the box space or is that port length too? Nobody seems to know, and the wider your port the more your tune would be off if you were calculating it wrong.
#13
Not you obv. but I was asking questions like where exactly does the port end (inside a slot port) because of end-corrections, if the port length continues for 1/2 of the port width further than the physical inside port-wall than when you measure from the center-line there's some space left, wouldn't you add it to the box space or is that port length too? Nobody seems to know, and the wider your port the more your tune would be off if you were calculating it wrong.
For instance, people get hung up on port displacement in a box. Does it matter? Do I have to account for it? What does it do to tuning? Reality, unless the box is small and the port is huge, it doesn't matter. A 1.5cuft box with a 4" port tuned to 35hz has a port length of 15.5" that has a displacement of 0.14cuft. If you did not account for that, your effective box volume is now 1.36cuft and the net tuning is 36.7hz. Does that matter? nope. Same thing with driver displacement most of the time. ie yes a 10W7 in 0.3cuft with a 6" vent is going to be a problem but if someone thinks this is a good idea from the beginning they have larger problems than physics..
OR how about bracing. Take that same 1.5cuft box and put 3 2x2 braces in it to stiffen the walls. You just ate up box volume but the stiffer enclosure is going to respond better so you will probably net out ahead. Correcting for the displacement of the bracing is a math excercise at best.
IMO the biggest things people screw up on with boxes is reinforcing them properly / dealing with internal issues.
#14
I know, but it makes so little difference, and other things will make more of a difference, that it just doesn't matter.
For instance, people get hung up on port displacement in a box. Does it matter? Do I have to account for it? What does it do to tuning? Reality, unless the box is small and the port is huge, it doesn't matter. A 1.5cuft box with a 4" port tuned to 35hz has a port length of 15.5" that has a displacement of 0.14cuft. If you did not account for that, your effective box volume is now 1.36cuft and the net tuning is 36.7hz. Does that matter? nope. Same thing with driver displacement most of the time. ie yes a 10W7 in 0.3cuft with a 6" vent is going to be a problem but if someone thinks this is a good idea from the beginning they have larger problems than physics..
OR how about bracing. Take that same 1.5cuft box and put 3 2x2 braces in it to stiffen the walls. You just ate up box volume but the stiffer enclosure is going to respond better so you will probably net out ahead. Correcting for the displacement of the bracing is a math excercise at best.
IMO the biggest things people screw up on with boxes is reinforcing them properly / dealing with internal issues.
For instance, people get hung up on port displacement in a box. Does it matter? Do I have to account for it? What does it do to tuning? Reality, unless the box is small and the port is huge, it doesn't matter. A 1.5cuft box with a 4" port tuned to 35hz has a port length of 15.5" that has a displacement of 0.14cuft. If you did not account for that, your effective box volume is now 1.36cuft and the net tuning is 36.7hz. Does that matter? nope. Same thing with driver displacement most of the time. ie yes a 10W7 in 0.3cuft with a 6" vent is going to be a problem but if someone thinks this is a good idea from the beginning they have larger problems than physics..
OR how about bracing. Take that same 1.5cuft box and put 3 2x2 braces in it to stiffen the walls. You just ate up box volume but the stiffer enclosure is going to respond better so you will probably net out ahead. Correcting for the displacement of the bracing is a math excercise at best.
IMO the biggest things people screw up on with boxes is reinforcing them properly / dealing with internal issues.
very well said Dukk. Unless you are building a specialty tuned box for SPL or SQ, small things can just be disregarded as long as you use some common sense and avoid situations like the 10w7 example.
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phat_71
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01-05-2009 06:46 AM