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What does a negative value mean on ISD Online?


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#1 of 3 Dave Poehlman

Dave Poehlman

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Posted December 14 2004 - 07:17 AM

I'm sitting here bored at work dreaming of building speakers and plugging T/S parameters into ISD Online. :b

Anyway.. I'm always looking for a bargain, so I plug in the parameters for the 4" HI-VI Aluminum midbass (which I think is a pretty sharp-looking driver):

Vas: .15 cuft
Qts: 1.08
Fs : 69 Hz

ISD Online tells me a sealed enclosure should be -.23 cubic ft!?!? and a ported enclosure should be 3.86 cubic ft with a hardly flat response that looks like this:

Posted Image

Are the wierd results a product of the driver parameters or something with ISD Online?

#2 of 3 Jason Dalton

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Posted December 14 2004 - 08:12 AM

It has something to do with the high Qts.

#3 of 3 Dave Poehlman

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Posted December 15 2004 - 02:05 AM

I see that now.. but, what does that tell me about the driver? What sort of box would it work best in?

I have a feeble grasp of the concept of Qts which is causing my confusion.

Qts has been explained to me as a driver's tendency to resonate at its Fs.

So, does this driver not care what size box it's put in since it's prone to resonate at 69Hz?

Maybe this crappy driver will finally get me to understand the significance of TS parameters.




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