[Dave Platt[_2_]]

And that's what's confused me for decades: HOW could a 16ohm speaker
present a LESSER load to the amp driving it than a 8ohm speaker?? Ohms
measure impedance, so a higher ohm figure instinctively means higher
impedance(resistance).

Higher impedance (resistance) means this: for whatever voltage the
amplifier is producing, the speaker will "resist" the flow of current
more than a lower-impedance load would do, and less current will flow.

Think of it like a water-hose. If you put a certain amount of water
pressure at one end, then a thin hose will resist the flow of water
more than a big fat hose would. Less water will flow through the thin
hose (less water current) than would flow through a fat hose, if they
both have the same pressure (voltage) being supplied.

An audio amplifier tries, very hard, to be a "voltage" source. It
takes the signal at its input, increases its voltage by a specific
ratio, and feeds this voltage to the load (speaker). At any given
signal level, it's trying to feed the same voltage (peak or RMS) into
whatever speaker is attached to it. This means that the amplifier
must be able to provide a higher current into a low-impedance speaker,
than for a high-impedance speaker.

Providing high currents is a tough job for the amplifier. When it's
feeding high currents to the speaker, it's pulling high currents
through its transformer (which heats up), through its rectifiers and
filter capacitors, and through its output transistors (which also heat
up).

So, in order to drive a really low-impedance load (say, 1 or 2 ohms)
to a substantial voltage, an amplifier has to have a really hefty
power supply... big transformer, heavy-duty rectifier, big filter
capacitors... and robust output transistors capable of handling lots
of current... and a big fat heat-sink to get rid of the excess heat
generated in the transistors. These all cost $$$.

Cheap amps don't have these. If you try to drive a low-impedance load
with such an amplifier, the high currents required by the load will
overstress the power supply or overheat the output stage, or both. If
you're lucky, the amp goes into self-protect mode and shuts down. If
you're not lucky, something burns up, all the Magic Blue Smoke leaks
out, and the amp won't work.