Technical parameters of Thiele and Small loudspeakers

THIELE AND SMALL PARAMETERS

These technical data are used to calculate the required loudspeaker volume.

Named after their inventors, the Thiele and Small parameters are used to characterize each loudspeaker, in order to calculate the required loudspeaker volume. They can be used to compare the capabilities of different loudspeakers, or to simulate the type of cabinet required for a subwoofer, for example.

• BL Loudspeaker motor force factor.
• Cas (m5/N) Acoustic compliance of loudspeaker surrounds.
• Cms (m/N ) Mechanical compliance of loudspeaker surrounds.
• Diam (m ) Emissive diameter of loudspeaker.
• Fs (Hz ) Speaker resonance frequency in free air.
• H. coil (mm) Height of loudspeaker voice coil winding.
• H. air gap (mm) Height of loudspeaker air gap.
• Les (mH) Electrical inductance equivalent to the compliance of the loudspeaker surrounds.
• Mas (Kg/m4) Equivalent acoustic mass of the loudspeaker's moving parts.
• Mms (Kg ) Mechanical mass of the loudspeaker's moving parts.
• N (% ) Loudspeaker efficiency expressed as a percentage.
• N0 or SPL (dB/W/m ) Loudspeaker efficiency expressed in sound level.
• Qes Coefficient of loudspeaker electrical surge at resonant frequency.
• Qms Coefficient of loudspeaker mechanical overvoltage at resonant frequency.
• Qts Coefficient of total loudspeaker surge at resonant frequency.
• Ras (Ohms ac.) Acoustic resistance equivalent to the internal losses of the loudspeaker surrounds.
• Rcc (Ohms ) Loudspeaker DC resistance.
• Res (Ohms ) Electrical resistance equivalent to the internal losses of the loudspeaker surrounds.
• Rms (Kg/s ) Mechanical resistance equivalent to the internal losses of the loudspeaker surrounds.
• Sd (m2 ) Loudspeaker emissive surface.
• Vas (l ) Volume of air equivalent to the elasticity of the loudspeaker surrounds.
• X. max. (mm) Loudspeaker linear peak-to-peak deflection.