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Why are low impedance speakers harder to drive than high impedance speakers

I don't understand the electrical reason for this. I look at it from a mechanical point of view. If I have a spring that is of less resistance, and push it with my hand, it takes little effort, and I am not working hard to push it. When I have a stiffer spring (higher resistance)  I have to work harder to push it. This is inversely proportional when we are looking at amplifier/speaker values.

So, when I look at a speaker with an 8 ohm rating, it is easier to drive than a speaker with a 4 ohm load. This does not make sense to me, although I know it to be true. I have yet been able to have it explained to me that makes it clear.  Can someone explain this to me in a manner that does not require an EE degree?

Thanks

128x128crazyeddy
atmasphere's avatar
atmasphere
11,803 posts
 
+1 on that for sure :)

I thought the notion that speakers, being transducers, vary much more in sound that do amps was universally agreed upon, and should therefore be selected first. The notion that power amps vary in character as much or more than do speakers is one I disagree with.
If you have no preference for tube or solid state then this is the way to go. If you have found that you prefer one over the other then you will need to get the amp first and then find a speaker to match. That is why in most cases, you start with the amp. It is tricky- to know that amp you have to hear it in a variety of circumstances to make an informed purchase. But if you do that, you are less likely to flush more $$$$$ down the loo trying to get the system to sound the way you want it.
mapman's avatar
mapman
22,200 posts
 
Interesting thing is you need amp and speakers together to make sound. Either one alone says nothing. So you can judge each on paper or do measurements but absolutely cannot judge how one sounds exactly without the other. Only the two together and each pairing sounds different.

Then as if that’s not bad enough there is this thing called room acoustics that means the same amp and speaker pairing will sound different depending not just on room but location in it.

However natural selection is at work. Only the strong will survive no matter what.
swampwalker's avatar
swampwalker
5,138 posts
 
I believe we have an early entrant for post of the year...Andrew-nz, way to go man!
swampwalker's avatar
swampwalker
5,138 posts
 
Damn auto-correct...Andrei-nz, that is.  
bdp24's avatar
bdp24
9,790 posts
 
Good point Ralph. It's great when ones taste in speakers and amps happens to allow a synergistic match---a tube amp with the Quad 57 ESL, for instance.
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