@britamerican wrote:
I think you are barking up a tree there @alexberger . No way crossover parts are heating as much as voice coil. Inductors probably not at all and what are we paying all that money for fancy resistors for??
The relevance here, coming down to practical usage, is that passive filter components heat up sufficiently to impact filter parameters, thus affecting the sound of the speaker to deviate from its intended design goals at changing, progressive SPL's. Surely this is not desirable, and that's just the workings within the crossover itself, apart from the fact that it's a "roadblock" by its mere existence; it effectively acts as a bottleneck between the amp and speaker, presenting a more challenging load to the amp that then has negative repercussions in its handling of the speaker and its drivers. Throwing gobs of money at fancy components doesn't really "add up" to anything, but rather potentially minimizes a nuisance.
@steve59 wrote:
Paul Klipsch gets quoted for saying he just wished somebody would make a quality 5 watt amplifier, (hopefully I didn’t butcher that quote too bad) I’m not sure how the math works, but I would think the difference in sensitivity can be evened out by using more powerful amps to compensate. Say, a pair of kilowatt amps for 86 db speakers could have the same dynamics as a horn design being driven by your favorite 12 watt tube amp? Having no educated qualification I would think heat would have to be addressed when designing for maximum spl?
Say you have properly sized all-horn speakers with a sensitivity sitting at no lower than ~105dB's (likely higher from the mids on up). That's a some 20dB discrepancy in sensitivity here compared to your 86dB speaker example. 12 watts on those horns, in theory, should be SPL-equalled by shoving ~1.2kW's into the low eff. speakers. Practically: good luck with that. Those horns by and large will likely cruise fairly effortlessly along with 12 watt peaks, whereas the low eff. speakers fed with +1kW's will be at the end of their ropes (if they haven't already passed unto those eternal audio fields) with power compression screaming its ugly face in heavy measure.
Look at the Tom Danley quote above - if power compression starts creeping in at 1/8 the rated AES power handling it suddenly makes sense to work towards maintaining prodigious headroom. That is, how to achieve any notable headroom with 86dB sensitive speakers and a fair max. peak SPL requirement at the LP of, say, 105dB's - without any effects of beginning power compression? The speakers would have to take no less than 1-1.5kW rated power just to avoid the beginning effects of power compression. Good luck with that, not to mention the amount of clean amp power that would require - with plenty of power to spare.
Many get by with much less power handling and capacity while feeling no shortage of dynamic prowess at the LP with lower eff. speakers, and if their max. SPL requirement is no higher than in the 90-95dB range it certainly lessens the need for higher sensitivity, power handling and capacity. That however is not to say more headroom won't make a difference here, certainly to those who knows the difference it can make, and to whom it's an important and desirable trait.