If I use a low pass filter in the speaker wire am I "wasting" power? It has been suggested to me that these devices, which keep the higher pitches off the woofer, are modifying an already amplified signal and thus wasting power. I wonder. If the speaker isn't producing those upper pitches, and if the filter doesn't heat up, where did the "wasted" energy go?
The speaker crossover has basically a low pass filter for the woofer anyway, and as far as wasted power, probably not. Audio signals are AC, and AC into coils and capacitor loads (that's basically the kind of load a speaker is) don't produce the resistive 'heat loss' like a purely resistive load.