the 8" & 10" went up the mid 1khz, and if memory servers me correctly the
review said you could use them in a 2 way system in a pinch.

standing waves have nothing to do with high freq.  if I said that it was a
mistake.

MARKETING, MARKETING!!!!

"Power" is a valid term for describing both AC and DC circuits - the
units just differ.  "Power" is simply the rate of energy flow in a
circuit (first derivative of energy with respect to time, or p=dw/dt).
This rate of energy flow is always called "power", whether we're
talking about DC or AC circuits.  The load in question can be purely
resistive, purely reactive, or a combination of the two - "power" is
still a valid term to describe the rate of energy flow through the
load.

In AC power equations, you have "true power", "reactive power", and
"apparent power" (this is the infamous "power triangle").  "Apparent
power" is the hypotenuse of the triangle, and "true power" and
"reactive power" are the two legs.

True power comes from the resistive portion of the load, and reactive
power comes from the reactive portion of the load.  True power is
measured in Watts, and reactive power is measured in VAR (volt-amps
reactive).   Apparent power is the combination of the two, and as
you've mentioned, is properly measured in VA (volt-amps).

Impedance is a combination of resistance and reactance.  The same
formula applies throughout, though.

True power is voltage squared divided by resistance.
Reactive power is voltage squared divided by reactance.
Apparent (or total) power is voltage squared divided by impedance.

So, voltage squared divided by impedance is a valid equation for
Apparent (or total) power in an AC circuit.  You are correct that in
AC circuits, there will be phase and time components in the voltage
and reactance to deal with as well.

As to your question about why speakers are rated using "Watts" and
"impedence", they're half-correct.  Speaker loads have both a
resistive component and a reactive component.  This combination of
resistance and reactance is "impedance", so they're correct to use
"impedance" to describe a speaker.

However, since speakers loads are both resistive and reactive, the
power delivered to them is both true power and reactive power.  Thus,
the total power delivered to the speaker is the combination of the
two, or "apparent power".  Apparent power should be measured in V-A,
not Watts.  Technically, stereo amplifiers should be rated in V-A as
well.  I figure more consumers understand "Watts" as a unit of power
than volt-amps, and as long as the amp manufacturers and speaker
manufacturers are on the same page, there's no real harm done in using
"Watts" instead of the correct "volt-amps"

Scott Gardner

Speakers are rated in watts in order to tell you how much electrical power they
can dissipate. Over 95% of the power delivered to a loudspeaker is dissipated as
heat by it's resistive element and can quickly barbecue the voice coil. Reactive
power (V-A) is what does all the work in a speaker. Since the reactive power is
not converted to heat, the maximum V-A delivered to a speaker will vary
depending on several things such as enclosure type, signal frequency, and driver
x-max among others. In this case the driver will reach it's excursion limit and
mechanically destroy itself.

Since your average loudspeaker is only about 5% efficient at best, it's
satisfactory to only provide it's maximum power rating in watts. If a speaker
bottoms out it will sound like crap and the listener will turn down the volume.
This inherent "built-in protection" protects the speaker from mechanical damage
resulting from excessive V-A.

Kevin Murray

Yeah, but that's like heaven to you.