4.6. Thiele/Small Parameters; 4.7. Calculated Parameters - powersoft IpalMod User Manual

15 : 4.6. Thiele/Small Parameters

The Thiele/Small parameters are electromechanical parameters that define the performance of a loudspeaker driver. T/S
parameters are provided by driver manufacturers.
In order to setup the system, you are asked to enter the following T/S parameters:
ffFs: loudspeaker resonant frequency in free air (Hz);
ffQes: electrical loudspeaker damping at resonance (unitless);
ffQms: mechanical loudspeaker damping at resonance (unitless);
ffVas: volume of air with the same acoustic compliance of the driver suspension in free air (cubic meters or liters);
ffRe: electrical resistance of voice coil (Ω);
ffSd: effective projected surface area of the driver diaphragm (square meters).
ffCms: suspension compliance (m/N)
ffMms: effective moving mass combining cone, coil, all moving parts and the acoustic load by the air in contact with the
loudspeaker cone (kg);
ffRms: suspension and all moving parts losses or damping (mechanical ohm);
ffBl: force factor, i.e. strength of the magnetic field times the length of the wire forming the voice coil (T·m or N/A).
Furthermore, the system takes into account the folloging data:
ffSound speed: speed of sound (meter/second)
ffRo medium density: air's medium density (kg/m3)

15 : 4.7. Calculated Parameters

The Power Control Manager derives the following data:
ffQts: total loudspeaker damping at resonance combining electric and mechanical effect (unitless):
ffCmes: electrical capacitive equivalent of the moving mass Mm (farad)*;
ffLces: electrical inductive equivalent of the suspension compliance Cm (henry);
ffRef eff. no: loudspeaker free air standard reference efficiency (unitless);
ffRef eff. no%: same as Ref eff. no in percentage;
ffRef SPL: reference sound pressure level (dB):
Ref SPL = 112 + 10 log(no).
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