"Richard Crowley" wrote in message
...
"andrew_h" wrote ...
Why is it that the lower the impedance for headphones,
the harder it is to drive????

It isn't.
Unless you wish to more carefully define "harder".

Agreed. It's usually harder for most portable ipod style players to drive
anything higher impedance *OR* lower impedance than the design value.


Thinking about speakers ..... say connected to an 8ohm
rated amp. If they were 32 ohms, then the amp's possible
power would be was less (than if the speakers were 8 ohm)....

25% of the power, to be exact.

Only if you ignore Current limitations.


So why is it so?

Ohms law. Any amplifier is limited in the amount of
voltage it can put out.

What amplifier has infinite current capability? Any amplifier has both
voltage *AND* current limits.

The higher the impedance of the
load (speaker, headphones, incandescent lamp, etc.,)
the less power the amplifier can source into the load.

Not necessarily. Many amplifiers will provide higher power into a four ohm
load than a two ohm load for example.
Some even provide higher power into 8 ohms than four, due to low current
capability.
(Of course their aren't too many 4 ohm headphones, but your comment
specifically mentions "speakers, incandecent lamps etc.")

MrT.