And so it came to pass, on 08-06-96 15:31,
   that Kurt J. Tischer spake unto John Holinsworth:
JH>>If my reciever had 6 ohm(minimum) speaker outputs, and I was running
JH>> 4 oh speakers. Would that damage the speakers or the reciever? Can
JH>> someone explain to me the difference in a 4 ohm to a an 8 ohm?
 KJT>         I am not sure if a difference of 2 ohms would damage the
 KJT> speakers or the receiver.
If he doesn't over-drive the speakers, it shouldn't hurt.
 KJT>         The difference between a 4 ohms and 8 ohms is the amount
 KJT> of resistance to current flow the speaker has.  The best way to
 KJT> see if your speakers will work on your 6 ohm minimum outputs, is
 KJT> to test the speakers on an ohm meter or multi-meter for their true
 KJT> resistance.  Even though speakers are rated at a certain ohmage,
 KJT> the true resistance can vary considerably.
An ohmeter or multimeter will NOT give the "true resistance" of a speaker, 
only its DC resistance.  Speakers are a *reactive* and *inductive* load, and 
the actual *impedance* (a function of resistance, reactance and inductance 
*together*) will vary depending on the frequency applied.
 KJT>         I once had a pair of JBL speakers that were rated at 8
 KJT> ohms, but when checked with an ohm-meter, the true resistance was
 KJT> found to be 5.6 ohms, which caused me to wonder why JBL would: 1.)
 KJT> rate the speakers at 8 ohms instead of 4, and 2.) let them pass at
 KJT> all as 8 ohm.
Because the eight ohm rating is a rating of *AVERAGE IMPEDANCE*.  Again, 
impedance will vary considerably depending on the exact frequency it's 
measured at, and will not be the same at a given frequency for any two 
different speakers, as different speakers' reactance and inductance 
characteristics vary widely.  
Since you'll never (intentionally) be feeding your speakers pure DC voltage, 
*resistance* measurements taken with an ohmeter are meaningless.  They will 
often measure close to the rated average impedance for a single driver, but 
in a multi-driver speaker system, will measure far differently because of the 
crossovers involved.  
For example, tweeter with a single capacitor inline as a crossover, will 
measure as an open circuit (infinite resistance) because the capacitor blocks 
DC voltage even though it passes AC signals.
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Q: Why don't blind people skydive?
A: It scares the heck outta their dogs!
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