ALL T/S Parameters explained - any mods want to put this in FAQ????
Theile-Small Parameters
This group of parameters outlined by A.N. Thiele, and later by R.H. Small, describe the electrical and mechanical characteristics of mid and low frequency loudspeakers operating in their pistonic region. These parameters are crucial for designing quality enclosures for sound quality or loudness.
Theile-Small Parameters
B Magnetic flux density in gap, in Tesla-meters (TM)
BL The magnetic strength of the motor structure.
C Propagation velocity of sound at STP, approx. 342 m/s
Cas Acoustical equivalent of Cms
Cmes The electrical capacitive equivalent of Mms, in farads
Cms The driver's mechanical compliance (reciprocal of stiffness), in m/N
D Effective diameter of driver, in meters
F3 -3 dB cutoff frequency, in Hz
Fb Enclosure resonance (usually for bass reflex systems), in Hz
Fc System resonance (usually for sealed box systems), in Hz
Fs Driver free air resonance, in Hz. This is the point at which driver impedance is maximum.
L length of wire immersed in magnetic field, in meters
Lces The electrical inductive equivalent of Cms, in henries
L Length of wire immersed in magnetic field, in meters
Ms The total moving mass of the loudspeaker cone.
Mmd Diaphram mass, in grams
Mms The driver's effective mechanical mass (including air load), in kg
n0 The reference efficiency of the system (eta sub 0)
dimensionless, usually expressed as %
p (rho) Density of air at STP 1.18 kg/m^3
Pa Acoustical power
Pe Electrical power
Q The relative damping of a loudspeaker
Qa The system's Q at Fb, due to absorption losses; dimensionless
Qec The system's Q at resonance (Fc), due to electrical losses; dimensionless
Qes The driver's Q at resonance (Fs), due to electrical losses; dimensionless
Ql The system's Q at Fb, due to leakage losses; dimensionless
Qmc The system's Q at resonance (Fc), due to mechanical losses; dimensionless
Qms The driver's Q at resonance (Fs), due to mechanical losses; dimensionless
Qp The system's Q at Fb, due to port losses (turbulence, viscousity, etc.); dimensionless
Qtc The system's Q at resonance (Fc), due to all losses; dimensionless
Qts The driver's Q at resonance (Fs), due to all losses; dimensionless
R Ripple, in dB
Ras Acoustical equivalent of Rms
Res The electrical resistive equivalent of Rms, in ohms
Revc DC voice coil resistance, in ohms
Rg Amplifier source resistance (includes leads, crossover, etc.), in ohms
Rms The driver's mechanical losses, in kg/s
Sd Effective piston radiating area of driver, in square meters
SPLo Sound Pressure Level, usually measured at 1 watt, at 1 meter in front of the loudspeaker
Vas "Equivalent volume of compliance", this is a volume of air whose compliance is the same as a driver's
acoustical compliance Cms (q.v.), in cubic meters
Vd Maximum linear volume of displacement of the driver (product of Sd times Xmax), in cubic meters.
Xmax Maximum peak linear excursion of driver, in meters
hope these help!!!!!
|
