Dayton Audio PS180-8 6-1 - Manual (Page 8)

Lm 94.5 94.7 94.7 dB characteristic sound pressure level
Sd
137.47 137.47 137.47 cm² diaphragm area
For accurate system modelling
“Large + Cold” parameters are preferable to “Small Signal”
parameters because they more closely reflect the parameters in their typical operating range.
Asymmetrical Nonlinearities
Asymmetrical nonlinearities produce not only second- and higher-order distortions but also a dc-part in the displacement
by rectifying low frequency components.
For an asymmetric stiffness characteristic the dc-components moves the voice coil for any excitation signal in the direction of
the stiffness minimum.
For an asymmetric force factor characteristic the dc-component depends on the frequency of the excitation signal. A sinusoidal
tone below resonance (f<fS) would generate or force moving the voice coil always in the force factor maximum. This effect is
most welcome for stabilizing voice coil position. However, above the resonance frequency (f>fS) would generate a dc-
component moving the voice coil in the force factor minimum and may cause severe stability problems.
For an asymmetric inductance characteristic the dc-component moves the voice coil for any excitation signal in the direction of
the inductance maximum.
Please note that the dynamically generated DC-components cause interactions between the driver nonlinearities. An optimal
rest position of the coil in the gap may be destroyed by an asymmetric compliance or inductance characteristic at
higher amplitudes. The module "Large Signal Simulation (SIM)" allows systematic investigation of the complicated behaviour.
Bl Symmetry xb(x)
This curve shows the symmetry point in the nonlinear Bl-curve where a negative and positive displacement x=xpeak will
produce the same force factor