# Where to Reaserch Tiele/ Small Theory?

customsound79
Copper - Posts: 65
Joined: August 07, 2004
Location: United States
Posted: March 25, 2005 at 8:11 PM / IP Logged
Mabey I'm reaching to deep, but I must know more. So far I have discovered WinISDpro and have been completely amazed at how accurate it is when I calculate the curves of every enclosure I've built( and measured with an RTA.) I muct know more!!!! What readings or websites do you suggest to put it all together?
My wife will never understand why, lucky for her!
DYohn
Moderator - Posts: 10,739
Joined: April 22, 2003
Location: Arizona, United States
Posted: March 25, 2005 at 8:26 PM / IP Logged

What do you want to know?  HERE's how to measure T/S parameters of your drivers if you want more accurate information to design with.

A good place to start learning is to click on "Basics" to the left and order some of the books linked there...

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Steven Kephart
Platinum - Posts: 1,737
Joined: November 06, 2003
Location: Oregon, United States
Posted: March 25, 2005 at 11:43 PM / IP Logged

Here's some excerpts from posts written by my boss, Dan Wiggins:

"There are only 6 fundamental physical parameters of a driver:

Re - the DC resistance of the voice coil (often called DCR). This includes the voice coil and tinsel leads. Measured in Ohms.
Le - the inductance of the voice coil. Usually measured in millihenries, sometimes microhenries.
Sd - surface area of the cone, usually measured in square centimeters.
Cms - compliance/stiffness of the suspension, usually measured in mm/N. That is, the suspension will sag X millimeters per Newton of force (there are ~4.5 Newtons per pound).
Mms - moving mass of the driver. Typically measured in grams.
BL - motor force factor of the driver. Measured in Tm (Tesla-meters) or N/A (Newtons per Ampere). I prefer the latter, because it is much more explicit about the force factor - X Newtons of force for every Amp of current you put through the driver (note that 1 Tm = 1 N/A).
Xmax isn't really a physical parameter of the driver - it's a "side effect" of a given driver design. Note that you can have the same 6 physical parameters, but Xmax values all over the place. And Xmax does not affect any of the derived T/S parameters.
T/S parameters are typically:
Fs: resonant frequency, set by the moving mass and compliance.
Qms: loss of the compliance, set by the Rms (mechanical impedance) of the suspension.
Qes: loss of the motor. Set by Mms, BL, Re, and Cms.
Qts: Q of the driver - combinatiom of Qms and Qes.
Vas: the stiffness of the driver, scaled by the cone size (Cms and Sd)."

"Vb is proportional to Vas (double Vas, double Vb). Vb is proportional to Qes squared (halve Qes, quarter Vb). This is for the same Qtc/alignment... And since Qes is inversely proportional to BL squared, if you double BL you cut Qes by a factor of 4, meaning the box volume for a given alignment is cut by a factor of 8.

Now, that is all well and good, but consider what Fb does in relation to Qts/Qes... Fb is inversely proportional to Qts, thus as you raise the BL, and lower the Qts, you raise the Fb accordingly. Double BL, cut Qts by a factor of 4, meaning Fb just jumped up 2 octaves!"

Steven Kephart

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