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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

Showing 5 responses by dlcockrum

dlcockrum's avatar
dlcockrum
2,105 posts
 
"Current production is a more useful indicator of amp "grunt" than rated wattage (or so I think)."

Nice job ghosthouse.


Best to you,
Dave
dlcockrum's avatar
dlcockrum
2,105 posts
 
Hi Charles,

Usually it comes down to approach: picking the speaker you love and then finding the right amp or vice versa, or in a fortuitous alignment of skill and circumstance, finding both without significant compromise.

Best to you Charles,
Dave
dlcockrum's avatar
dlcockrum
2,105 posts
 
Whoa, Ralph, you took my statement out of context. Here is what I actually said:

"Usually it comes down to approach: picking the speaker you love and then finding the right amp or vice versa, or in a fortuitous alignment of skill and circumstance, finding both without significant compromise."

Vice versa means "with the main items in the preceding statement the other way around", thus indicating your approach as one of two alternatives.

To say, as you did, that the first approach (speakers then amp) does not also work is counter indicated by many fine sounding audio systems selected based on that approach.

Best to you Ralph,
Dave
dlcockrum's avatar
dlcockrum
2,105 posts
 
Perfectly stated Charles. Many roads...

Dave
dlcockrum's avatar
dlcockrum
2,105 posts
 
atmosphere: "One other point not previously mentioned is the effect of speaker cables! At lower impedances they tend to be far more critical, where shorter distances and much larger gauges are required to prevent loss of definition and impact. This can be a pretty big deal as the series resistance of the speaker cable can have a pretty dramatic effect on the effective output impedance of the amplifier! By contrast the speaker cables are far less critical at 16 ohms- which is why a lot of us kids got by with hardware store zip cord in the old days."

At the risk of taking this thread into the contemptuous nether regions of many others (please no!), this may explain a lot regarding contrary experiences of many on this forum regarding speaker cables' impact on sound.

Good point Ralph.

Dave 

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