Hello Folks, can any one tell me why that when you put an iron laminated bar inductor (say 5.6mH .5 dcr) in series with a driver that has a high impedance peak/s (single or dual peak depending on box type.. sealed or vented) that you get a peak in the bass response that appears to correspond to the trailing edge of that peak >), which is usefull in some sub driver applications but not so in three way applications.
capacitive speaker below resonnance
Remenber your speaker is resistive only at resonnance, and will be inductive above resonnance and capacitive below resonnance, so adding an inductive device in series with a capacitive load ( speaker below resonnance ) will reduce resulting impedance and increase current.
Remenber your speaker is resistive only at resonnance, and will be inductive above resonnance and capacitive below resonnance, so adding an inductive device in series with a capacitive load ( speaker below resonnance ) will reduce resulting impedance and increase current.
Thanks audiofan, also just found this description from partexpress forum which sort of makes sense
"Most woofers, whether in a sealed or vented box will have a large impedance peak in the upper bass range. On the upper side of this peak, where the impedance is falling back towards Re, the impedance is primarily capacitive with a large negative (capacitive) phase angle. When a large value inductor in placed in series with the woofer, its inductance will interact with the capacitance of the impedance peak and produce a significant peak in the frequency response a little higher than the freqency of the impedance peak"
"Most woofers, whether in a sealed or vented box will have a large impedance peak in the upper bass range. On the upper side of this peak, where the impedance is falling back towards Re, the impedance is primarily capacitive with a large negative (capacitive) phase angle. When a large value inductor in placed in series with the woofer, its inductance will interact with the capacitance of the impedance peak and produce a significant peak in the frequency response a little higher than the freqency of the impedance peak"
impedance plot
Look at this wonderfull graph, one ef the easiest to read I ever found
http://www.audioheuristics.org/projects_gallery/Usher_satellites/usher/graphs/Usher_impedance.GIF
Look at this wonderfull graph, one ef the easiest to read I ever found
http://www.audioheuristics.org/projects_gallery/Usher_satellites/usher/graphs/Usher_impedance.GIF
This is why you always use simulation software to design your crossover using the actual impedance and frequency responses of the drivers you plan to use in the design. This is also why trying to use a simple highpass/lowpass crossover around 100Hz isn't going to work. Drivers are NOT simple resistive components.
This is backwards. Above the resonance frequency the speaker is capacitive and below the resonance frequency it is inductive.
The electrical model has an inductor representing compliance in parallel with a capacitor representing mass. Above resonance inductive reactance is greater than capacitive reactance, and the combination has net reactance that is capacitive. Below the resonance frequency the exact opposite is the case, and net reactance is inductive.
This is counter-intuitive but the truth.
Regards,
cT
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