Relationship among T/S Parameters

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I mean, I got some very basic understandings about those T/S parameters. But how do they affect one another?

For my project which is now on planning, someone suggested this 15" Monacor woofer to me:

http://www.monacor.de/typo3/index.ph...ukatid=&brand=

Here I digested some of its T/S parameters:

Resonant frequency (fs) 23Hz
SPL (1W/1m) 96dB
Suspension compl. (Cms) 0.3mm/N
Moving mass (Mms) 160g
Mech. resistance (Rms) 3.1kg/s
Mech. Q factor (Qms) 6.36
Electr. Q factor (Qes) 0.29
Total Q factor (Qts) 0.26
Equivalent volume (Vas) 284 l
DC resistance (Re) 2 x 6£[/ 3£[
Linear excursion (XMAX) ¡Ó7mm
Eff. cone area (Sd) 850cm2
Volume displacement (Vd) 595cm3
Force factor (BxL) 16.72Tm


TBH, I suspect some of the numbers above.

According to my basic understanding, the fs is determined by the moving mass and the suspension compliance. Now its 160g of Mms for a 15"er seems quite heavy, so 23Hz is possible.

Moving on to the SPL, it should be tightly related to the ratio of BL and Mms. Its BL is a moderate 16.7TM, but it's pushing a relatively heavy cone of 160g. Is it possible to produce 96dB/w/m?

Or it's measured at 2.83V into its paralleled duo voice coil? Thus a +3dB gain (by cheating)?

In addition, the 0.26 of Qes dominates total Q (Qts), which is quite low, means this motor is quite strong for the cone. But how do BL / Qes / Mms affect one another? Is there any mathematical relations?

I don't remember any other driver comes with such combinations: moderate BL (16.7), heavy cone (160g), Low Q (0.26), Low fs (23Hz), pretty high SPL (96db/w)...

Any thoughts?

[bjorno]

Hi, There is nothing wrong with those parameters.

If you cross calculate you will only find that rounded off values must been used when advertising this driver.

The first thing to do with this type of extensive data is always to figure out how the TS data is collected, i.e. how the driver is hooked up, parallel, series or single coil, before you check the consistency. In this case it’s with the coils in parallel.

b

1(1)

[AndrewT]

Hi,
I'm inclined to agree that most of the parameters look OK if we assume the VCs are wired in parallel for the sensitivity test and should read~96db/2.8V/m and not 96db/W/m.

[MaVo]

There are some formulas: http://en.wikipedia.org/wiki/Thiele_small

[CLS]

Thanks a lot Now I have a clearer picture.

[jupiterjune]

Moving on to the SPL, it should be tightly related to the ratio of BL and Mms. Its BL is a moderate 16.7TM, but it's pushing a relatively heavy cone of 160g. Is it possible to produce 96dB/w/m?

A key parameter that affects SPL is Vas -- the equivalent spring in air volume that the motor is pushing. 284 liters equals 10 cubic feet -- a rather small spring. So these numbers don't seem immediately suspicious to me. Look at some car subwoofer Vas figures -- when you see a 15" sub with a 2 cu foot Vas and 96 db SPL -- be suspicious!

JJ