Let's see if I can remember how all this works.....
Others more knowledgable can make corrections.....
"u" = ohms.
(Actually it's the greek letter "mu".)
Ohms is the internal resistance of your speaker to the flow of electicity. If you double the ohms, you'll need twice the wattage to drive the speaker.
"w" = watts.
Watts is the amount of power your speaker is able to handle; or your amplifier is able to deliver at a given resistance (in ohms). Deliver more watts to your speaker than it's rated to handle and you'll get anything from distortion (other than that caused by the amplifier) to actually blowing the speaker.
Stereo amplifiers are rated for distortion at their maximum power output. High end equipment has distortion levels that are, for all practical purposes, imperceptable. Low end equipment, such as the amplifiers attached to an MP3 player, have high distortion levels. MP3 players sound is clear and clean in it's initial reproduction; it's distorted in the amplifying stage.
An amplifier rated at 4 ohms/7 watts would actually only be able to deliver 3 1/2 watts into a speaker rated at 8 ohms resistance.
In your example..... My Bose speakers for my home stereo system are 150 watt/8 ohms; I drive them with a 100 watt/8 ohm per channel Onkyo amplifier. Anything much above 1/3 volume and I'll have my upstairs neighbors pounding the floors! A 4u/7w amplifier would barely deliver sufficient power to drive the speakers enough that they could be heard.
I know what I'm trying to say..... I only hope that I'm saying it in an understandable manner.....
me!
What'll it be tonight? /ubbthreads/images/graemlins/confused.gif
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