I'm probably opening a big can of worms here, but I am wondering if Thiele Small parameters are really all that important for a subwoofer if the sheet also just comes right out and says how much air space the box needs to be??
I'm looking at a subwoofer that says it needs 0.75 cu. ft. of sealed air space and it also has this big list of other values like Qts and Vas and all that stuff.
Also, can you calculate, within reason, the amount of space that a sub displaces inside the box so you can build to allow for that?? I'm looking at another sub with the same internal box volume requirement, 0.75 cu. ft., and it does NOT say how much to allow for speaker air displacement. I just measured the magnet width and height, and the cone depth and width and all to try to come up with a figure to allow when building a box.
Replies (3)
audeogod on 12/17/2004 21:28:57
Oh, by the way, ...I DO KNOW... to use volume formulas for the cone(a cone formula) and the magnet(a basic cylinder) to calculate. Just wanted that to be clear, that I am not trying to redneck the figure by just measuring the depth in inches and guessing at how much it would take up. Just want to know if this will work or not.
uochronos on 12/17/2004 22:09:08
if you want to go with a simple sealed box the the parameters dont matter a whole lot if you have a recomended volume at your disposal...
however if you want to build a more advanced box say a ported, bandpass, transmision line, horn, etc then the parameters are going to help you out alot in perfecting your box design.
if the woofer doesnt say how much volume it takes up you can probaly request that info from the company or do like you said you did and add up the displacement of the magnet and the cone and add them together.
Chronos
PS
i probaly left some stuff out here but swez and some of the others well be able to give you a much more in depth awnser.
swez on 12/17/2004 22:59:31
We have some lee-way here on sealed enclosures. You have a good +/- 10% internal volume here to play with and still sounds good. Ported and BP are a bit more precise in their needs.
If one were to profile 10 subs (same brand & model) and actually measure the real T/S parameters, they will be slightly off from specs. Some may be more than 20% out of tolerance in some T/S specs... but
who has the time and test equipment to proof it out?
T/S specs are a good tool for determining basic sub performance charateristics. But, the published specs, don't always match the real deal you get on a given driver. T/S specs have hidden variables we often do not recognize. Unless you are building a super SQ system, one may not hear much of a diiference.
Swez
I'm looking at a subwoofer that says it needs 0.75 cu. ft. of sealed air space and it also has this big list of other values like Qts and Vas and all that stuff.
Also, can you calculate, within reason, the amount of space that a sub displaces inside the box so you can build to allow for that?? I'm looking at another sub with the same internal box volume requirement, 0.75 cu. ft., and it does NOT say how much to allow for speaker air displacement. I just measured the magnet width and height, and the cone depth and width and all to try to come up with a figure to allow when building a box.
Replies (3)
audeogod on 12/17/2004 21:28:57
Oh, by the way, ...I DO KNOW... to use volume formulas for the cone(a cone formula) and the magnet(a basic cylinder) to calculate. Just wanted that to be clear, that I am not trying to redneck the figure by just measuring the depth in inches and guessing at how much it would take up. Just want to know if this will work or not.
uochronos on 12/17/2004 22:09:08
if you want to go with a simple sealed box the the parameters dont matter a whole lot if you have a recomended volume at your disposal...
however if you want to build a more advanced box say a ported, bandpass, transmision line, horn, etc then the parameters are going to help you out alot in perfecting your box design.
if the woofer doesnt say how much volume it takes up you can probaly request that info from the company or do like you said you did and add up the displacement of the magnet and the cone and add them together.
Chronos
PS
i probaly left some stuff out here but swez and some of the others well be able to give you a much more in depth awnser.
swez on 12/17/2004 22:59:31
We have some lee-way here on sealed enclosures. You have a good +/- 10% internal volume here to play with and still sounds good. Ported and BP are a bit more precise in their needs.
If one were to profile 10 subs (same brand & model) and actually measure the real T/S parameters, they will be slightly off from specs. Some may be more than 20% out of tolerance in some T/S specs... but
who has the time and test equipment to proof it out?
T/S specs are a good tool for determining basic sub performance charateristics. But, the published specs, don't always match the real deal you get on a given driver. T/S specs have hidden variables we often do not recognize. Unless you are building a super SQ system, one may not hear much of a diiference.
Swez
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