sensorless DSP cone excursion limiter

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Replying to myself 1,5 years later .. :) I just finished the project and what I did so far on this topic/area is adding a low shelf (boost) to compensate for the 6 dB/octave roll-off of the OB woofer below 200 Hz and at the same time add an 8th order high pass filter with cutoff 20 Hz since my woofer's freq response below 40 Hz drops steeply anyway and i thought the high pass might be good to add some protection against high energy in the low area below 40 Hz.
 
Replying to myself 1,5 years later .. :) I just finished the project and what I did so far on this topic/area is adding a low shelf (boost) to compensate for the 6 dB/octave roll-off of the OB woofer below 200 Hz and at the same time add an 8th order high pass filter with cutoff 20 Hz since my woofer's freq response below 40 Hz drops steeply anyway and i thought the high pass might be good to add some protection against high energy in the low area below 40 Hz.

I'm glad you were inspired to implement these filters... however, I don't see how that is related to the original topic - excursion limiting. That's only supposed to kick in when the cone is exceeding some predetermined threshold (e.g. Xmax, or some distortion threshold, etc.). Otherwise the "limiting" action is out of circuit.

You have simply implemented some filters that are active all the time. Please correct me if I am wrong, but from what you wrote I believe that is your approach. It's just continuous-time filtering. It's will not limit excursion as power or input level is increased.
 
I'm glad you were inspired to implement these filters... however, I don't see how that is related to the original topic - excursion limiting. That's only supposed to kick in when the cone is exceeding some predetermined threshold (e.g. Xmax, or some distortion threshold, etc.). Otherwise the "limiting" action is out of circuit.

You have simply implemented some filters that are active all the time. Please correct me if I am wrong, but from what you wrote I believe that is your approach. It's just continuous-time filtering. It's will not limit excursion as power or input level is increased.
Correct, I just wanted to give an update on my project. It’s indeed not a limiter. In practice though my thought is that a 20 Hz highpass doesnt hurt and I dont know if this ever occurs but if some <20Hz (or dc) high amplitude signal is sent it wont reach my woofers. And >40 hz I expect I wont reach over excursion as long as I get to know my woofers a bit and learn what music levels are safe and dont use weird music or test signals with extreme and unnatural bass amplitudes. But still: Im not denying that a real (nonlinear) excursion limiter would be a great feature.
 
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