4 ohms, 8 ohms, how to translate?

Here is a good example on how to figure ohms.............

If your amp says 500W/ch @4ohms. That means ur amp will push 500W (or close to it) out each channel (1000W total) to a 4ohm speaker. When you connect an 8ohm speaker to this channel u lose some power to that speaker you will only get about 350W. (don't quote me on this).
When u run two 8ohms speakers in parallel (daisy chaining) u have created one 4ohm speaker.

So run from your amp to the 8ohm speaker and daisy chain ur two speakers. Now ur amp sees 1, 4ohm speaker and it will get fed 500W out of that channel. This 500W will be divided between your two speakers 250W per speaker.

Did this help any??

Yeah, a little bit, thanks!

Here are some specs I pulled off the internet for a Peavey PV1500 power amp :
Stereo Mode: 4 Ohms: 500 Watts RMS x 2
Stereo Mode: 8 Ohms: 300 Watts RMS x 2
Bridge Mode-Mono: 8 Ohms: 1000 Watts RMS

So if you are using the amp in stereo mode it will put out 500 Watts into each of two 4 Ohm speakers provided that they are connected one to a channel . However , if you have two 8 Ohm speakers with one connected to each channel then the output is reduced to 300 Watts per side . The third Mode ( Bridge Mode-Mono ) is usually activated by sliding a switch on the back of the amp . In this mode , both channels can be driven by one input signal and the output is doubled , especially useful in subwoofer applications where a great deal of power is needed .
As you can see from the above example , if you increase the speaker load ( i.e. , use an 8 Ohm speaker rather than a 4 Ohm speaker ) you will get less power from the same amp . So , as long as your 8 Ohm speaker can handle 300 Watts you should be safe in using it . You can always add another 8 Ohm speaker per side and then your amp would put out 500 Watts per side with 250 Watts going to each speaker . Just make sure they are connected in parallel .

LazerKrust

I am no electronics guy, but Ohms is simply a measurement of resistance.
A lot of things affect resistance. Heavier gauge wire can carry more electrons through it than a small thin wire so it would have less resistance. Think of it kind of like water flowing through a pipe. The bigger the diameter pipe, the easier it is for more water to flow through it.

Most amps operate most efficiently at 4 Ohms. However, the better amps (and more expensive) can handle as low as 2 Ohms.

You will see specs like 250W @ 4 Ohms, 180W @ 8 Ohms. This means the amp can produce 250W (usually per channel) with a 4 Ohm load. But a 8 Ohm load offers more resistance. It is kind of like driving with your foot on the brake pedal. So, with a 8 Ohm load this amp can only produce 180W.

The important thing is not to put a load that is lower than the amp calls for. If you do not see any info on the back of amp or in it's manual that says it can handle a 2 Ohm load, then don't try to do that. If you hooked up two 4 ohm speakers in parallel to that amp, that would be a 2 Ohm load. Now, too much current flow will be running through your amp. It was not designed to handle that much. The amp will probably overheat very quickly and burn up. A soundman once told me it is like turning your amp into a toaster!

Most PA speakers are wired parallel (but not all). So, make certain of that before you experiment. Either consult the manual or send off an e-mail to the manufacturer.

2- 8 Ohms speakers in parallel = 4 Ohm load
3- 8 Ohms speakers in parallel = 2.67 Ohm load
4- 8 Ohms speakers in parallel = 2 Ohm load

2- 8 Ohms speakers in series = 16 Ohms load
3- 8 Ohms speakers in series = 24 Ohms load
4- 8 Ohms speakers in series = 32 Ohms load

Big difference between wiring speakers parallel or series.

You could run, say, a 16 Ohms speaker cabinet off the amp I described above. It will work and should not damage the amp, but the amp will not be able to put out much power.

Usually, you get about 65-70% of the power at 4 Ohms vs. 2 Ohms
Usually, you get about 65-70% of the power at 8 Ohms vs. 4 Ohms
Usually, you get about 65-70% of the power at 16 Ohms vs. 8 Ohms.

And so forth.

So, if you hooked up two 8 Ohms speakers wired in series (16 Ohm load) to the amp described above, you would get about 65-70% of 180W which would be around 117-126 watts. Like I said, it's like having your foot on the brake. And the two speakers would split the watts, so each individual speaker would get around 60 watts or so. You are just wasting your amps power with a setup like this.

Too low ohms is like going down a steep hill with no brakes at all. Your vehicle would race higher than it was designed for and shake itself apart or burn up.

I know these are silly analogies, but they give you the basic idea.

Just picking up on Wes's reply to Lazercrust. What is the actual difference beteween parallel and series. I fullyunderstand the ohms v power bit, but I am not sure if I would know which configuaratin is which. When people describe 'daisy chaining' what is that and what is connected to what? I have two speakers, each with two speakon connectors to each. If I plug the amp to one speakon connector, then run a wire from the connector right next to it on the same speaker away to the second speaker, is that parallel or series? Whichever one that is, what set up would constitute the other...if you see what I mean.