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MCPete 9th December 2009 08:12 PM

calculating Qms' of RDO with T/S parameters
As formulated by Ron E (a frequent contributor here),

Qms' = 2*pi*Fs**Mt/Rmt


Qms' = modified mechanical Q in free air of a DVC woofer with one of the voice coils made unenergized and resistively damping the driver given a resistor across its terminations

Fs = free air resonance frequency

Mt = total moving mass of the driver

Rmt = total mechanical resistance = mech. resistance of the driver Rms + resistive damping

Based on relations between the fundamental mechanical parameters of Ron E's equation and the T/S parameters, I derived

Qms' = Rt*Qms*Qes/(Re*Qms + Rt*Qes)


Rt = Re + Rx

Rx = resistance of the resistor connected across the terminations of the unenergized coil

Qes = electrical Q of the DVC driver with terminations of one of the driver's coils open and unconnected.

This should be helpful to anyone using RDO as T/S parameters are the ones usually on the spec. sheet for a woofer and not all of the mechanical parameters required for calculating modified Qms by Ron E's equation.

Please let me know if think that my equation is faulty or if you would like to see its derivation.



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