Thiele-Smallis the name given to a number of transducer
(loudspeaker) performance characteristics, first developed by Neville Thiele
and Richard Small.
These characteristics or parameters are used to analyse the behaviour of
a given transducer in any of a number of different loudspeaker cabinet
designs. Most manufacturers publish the Thiele-Small parameters for transducers
that they sell.
Below is a brief description of the Thiele-Small parameters used by the
ISHTEK speaker design applet.
Fs - is the free air resonant frequency of the transducer.
Qes - is the electrical Q of the transducer.
Qms - is the mechanical Q of the transducer.
Vas - is the compliance volume of the transducer.
Sd - is the area of the transducer diaphraghm.
Xmax - is the maximum displacement limit for the transducer
before ten percent (10%) distortion is reached.
Re - is the DC electrical resistance of the voice coil.
No - is the reference efficiency of the transducer.
Pe - is the continuous thermal power rating for the transducer.
Some manufacturers also quote Vd, which is the maximum volume displaced
by the diaphragm. Note that Vd equals Sd multiplied by Xmax.
(Vd = Sd * Xmax).
