Current Questions


More and more, I see the word “current” in audio reviews. The reviewers warn me that I’ll “need lots of current” for a given speaker but they don’t explain exactly what it is I need or how many “lots” is. I’ve looked at a few “Electronics For Dummies”-type sites but I’m still confused. A few questions:

 

—What is current?

 

—When someone writes, “These speakers need a lot of current,” what do they mean? Is sensitivity involved? Impedance?

 

—On the amplifier end, what specification measures current?

 

—Are there subjective considerations at work in that spec? The number of watts doesn’t tell me everything about loud an amplifier sounds. Does the number of [whatever measures current] similarly leave things unexplained?

 

—Everyone asks, “How many watts?” No one asks, “How much current?” Is it really so important?

paul6001

Showing 2 responses by falconquest

we start with the speaker, and determine which amplifiers will work and which will not, and then go from there.

We can talk about current in isolation, but it seems easier if we started with an example of what speakers you wanted to consider running.

 

Not to get too technical but in terms of current, since the speaker is a "load" can we not say that the speaker will have a certain current "draw" in order to reproduce the signal being sent? If the amp does not have the capability of providing that draw, is that what leads to the amp clipping? In other words, the question isn't so much amp output current but, as some have been saying, the amount of current draw by the speaker. One must understand that and choose an amp that will meet that requirement. I have never seen specs. for either but I have experienced it.
 

I can't believe no one has answered the OP's original question. What is current? To do so we need to go back to electricity 101. Forget Ohm's law for now. Think of electricity as the flow of water in a pipe. Current is like the flow of water. It is actually the flow of electrons. Voltage is the pressure that is causing that flow. Resistance is anything that restricts the flow in any way such as a restriction in the pipe or water flowing over rocks etc. If you think of an electrical circuit in terms of plumbing, it's a very good analogy.