I like to protect gear from whatever might come, so I like lamps and polyswiches. I would
be almost as happy with a frequency-selective limiter that could independently account for
the thermal and displacement limits of the tweeter, mid and woofer (with appropriately
different time constants - an even greater challenge), but the reality is that a lamp in
the tweeter circuit handles 80% of abuse, so it's cheap insurance.

But an interesting twist is that with the simple 2nd order HPFs I have been trying (with a
very high Fc, eg 8 kHz, to flatten CD horn response and match sensitivities), a lamp or
polyswitch in the INPUT to the crossover has the nice benefit of also seeing more MF, and
so potentially account for both thermal and displacement limitations. Admittedly the time
constants cannot be independent as would really be required, but it's still better than
having the lamp in the crossover output circuit, and a LOT safer for the amp, which
becomes UNLOADED when the protection operates, instead of shorted.

Tony