Originally Posted by MichaelJHuman
I still think impedance dips represent the worse case scenario, and don't have to be viewed as something of much concern.
More of a concern, in my mind, if you send a signal which results in the speaker "unloading" and exceeding it's mechnical limits. I would be concerned about damage.
A brief overload, which results in a low impedance presented to the amp which results in a condition the power supply can't keep up with, seems like a minor issue. Unless the amp/receiver takes a long time to recover ( I have read that this is a possibility in some amps.)
I feel it's maybe best to avoid speakers known for totorting amps. Plenty of good speakers out there which behave pretty well, right?
Whoa man! Now you're talking something that we should actually worry about, but [insert name of audio rag here] never told me about it, so now I'm going to re-regurgitate a ton of buzzwords in your face!
In all seriousness - I agree with your point about not picking nightmare load speakers, with some reservations (of course); seems common sensical to me!
Where I'd have reservations is roughly thus:
Going back to Ohm's Law - if the amplifier (any amplifier) can drive X W into XYZ R, it will work. So if you've got a speaker that drops down to 4 ohms at some point, and the amplifier has 4 ohm numbers (and I'm really okay with manufacturer's dynamic output values here) it shouldn't have a problem. Speakers that drop down to 1 ohm or less usually do it at one side of the FR spectrum and the advantage is: on the HF, there's usually not much content (and that that is, doesn't want a lot of power), and on the LF, it should be handled by an xover (*should*). And when all of that fails and you don't feel satisfied, the RMX5050 (or some other hilariously huge amplifier) is mere clicks away, and sure to destroy whatever hoity-toity speakers you're worried about with it's near bottomless amounts of output power.
As far as bass sounding "weak" or "bad" - I'm inclined to lean on room acoustics as the bigger deal here (or the speakers themselves, but that's it's own hornet's nest - plenty of people believe their speakers can never be the problem). If the amplifier can't "ring the bell" into whatever load, it'll either start clipping, it'll overheat, or it'll go into protection - sometimes all three. Sure, THD might rise with that dip, but even at 1%, why do we care? Not like the speaker is somehow bettering that...