When referring to sound systems: What do you know about ohms

[pyrate83]

Ok, I know I work for Radioshack and probably should know the answer to this but I don't. I have a couple of older floor speakers but am getting a new receiver and it says I should use speakers with a nominal impedance of 8 to 16 ohms. I don't know how many ohms my floor speakers are and am not sure what will happen dare I hook them up to the new receiver.

Anybody know what the hell I'm talking about or could maybe shed some light on the situation?? I also should add that I will be adding more speakers soon as well.

Thanks!

[Craig Tucker]

A rough guide to finding the impedance of your speaker is to measure the resistance (ohms) across the terminals of the speaker with a multimeter, and multiply it by 1.3. This will give you the impedance (ohms).

http://wolfstone.halloweenhost.com/HalloweenTech/spkimp_SpeakerImpedanceMatching.html#Why

[MackemX]

this is the only ohms I have heard of recently HERE

hmmmmmmm, the face looks familar, where've I seen it before?

[MackemX]

can you get to see inside your speakers as it may have it on the back of the magnet if you can

[i_am_dave]

Good old Ohms law. current = voltage / resistance.
The lower your resistance, the current that your amplifier will have to produce.
More current = more heat and more strain on your amplifier, perhaps reducing its life.
Think of it this way, a dead short=0 ohms, and you know what happens when you short something out.

[bugster]

The Ohms value referred to on speakers is an impedance, not a resistance, as inferred by Craigs answer.

The vast majority of speakers on the market today are 8 0hms impedance, though not all. It should state the impedance somewhere on the back of the speaker, usually near the terminals, along with the max input power in watts.

[pyrate83]

Yeah, I actually already checked the back of the speaker but no luck there. The boxes are old but in great shape and the speakers were replace only a few years ago. I might try seeing if the back of the speaker itself says or take Craig's advice and borrow a multimeter from work and get the true answer.

Thanks guys.

[Devanshu]

Um...the only ohms I've ever encountered are in physics and ap physics. It's a unit of measurement for resistance. I'm taking a stab at it but I'm not sure if it's right or not...here goes: less ohms = higher volume?

[Devanshu]

Pyrate...you got PM

[Craig Tucker]

Resistance Vs. Impedance

[pyrate83]

So since these are older speakers they are prolly 8 ohm speakers right? B/c from what I understand the older speakers are going to be 8ohms but some of the newer ones could be 2 or even 4 ohms.

[bugster]

Resistance Vs. Impedance

Nice article Craig, I never could understand the difference, until now!

[i_am_dave]

Nice article. Your multiplier of 1.3, shouldn't that have been 1.21(1/sqr(2)) instead?

I am trying to remember all the old AC fundamentals classes I took over 20 years ago.