This is what you said:
Low frequency resonance of driver that is stimulated by signals that have passed from active crossover, through amplifier, through (useless) protection capacitor, produces back EMF that sees (useless) protection cap, which will partially pass EMF from driver back to amplifier, and (useless) cap will reflect remainder back again to voice coil. I say useless, because the bigger the cap, the less protection it offers from crossover failure, or operator error. The smaller the cap, the more defeats purpose of active crossover.
Many IM difference components generated by driver are much lower than driver resonance and again, big useless protection cap in circuit gets in way of amplifier's damping capabilities.
What if a cap value at the turn over frequency was inserted in the speaker feed?
That is one passive pole.
Then add another passive pole, at the same turn over frequency, to the input of the Treble amplifier.
Those together give roughly a 2pole attenuation of a wrong signal and may just about protect an expensive driver from damage.
They also give 2poles of a complex multi-pole roll off.
The active feed from the DCX is now two poles less.
That is one passive pole.
Then add another passive pole, at the same turn over frequency, to the input of the Treble amplifier.
Those together give roughly a 2pole attenuation of a wrong signal and may just about protect an expensive driver from damage.
They also give 2poles of a complex multi-pole roll off.
The active feed from the DCX is now two poles less.
No need to give up. No need for cap. Just good operating procedure, and amplifiers with high damping factor (low output impedance).
Interesting. Not implementable with my current crossovers, but I'll give it some thought if/when I replace the DCXs with something more-custom. That's a long way away though, as I suspect any work I do on xovers in the near future will be merely replacing the IO boards on the DCXs.
Exactly why fpitas and I pulled the capacitors out of our actively crossed systems 😉.
He "gave up" on explaining that to you, because you don't seem to get that he removed his capacitors because they lessened the damping available from the amplifier.
Sorry for being exceptionally dense. Somehow I manage to miss wording in specific post. Purely my fault, I am embarrassed and offer my humble apologies.
Absolutely!
Absolutely!
If you are using an active cross over, you don't insert capacitors in series with the HF as you will create phase shift at 3 and 6DB points. Rely on the quality of the HF amplifier to protect the drivers.
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