speaker compatibility (1 Viewer)

[AndrewKra]

I have speakers that are rated at 4 ohms. I was wondering if this meant I cant even get a receiver that is more than 4 ohms or if i can get one but just shouldnt turn the speakers up too far?

 

[Jack Briggs]

Andrew: "Ohms" are specific to speaker systems. And the resistance (i.e., 4 ohms, 8 ohms, 6 ohms, whatever) varies over a speaker's response curve. So, what you have is a nominal rating. In general, most transistor amplifiers put out more power the lower the ohm-rating at a given level of the frequency response. JB

 

[AndrewKra]

ok thanks, but does that mean i can use a 8 ohm receiver with my 4 ohm speakers.

 

[Ted Lee]

you can, but you should be careful. if you use a speaker system with a lower impedance rating then the receiver can handle, you may make the receiver "work harder" then it's designed to.

here's the analogy i usually use.

my honda is rated at 8-ohms and can go 60 miles an hour. if i use 4-ohm speakers, now my car is going 120 miles an hour. yes, it can do that ... but for how long before the thing blows up?

 

[AndrewKra]

so I should really be more worried about the receiver frying than the speakers?

 

[Bob McElfresh]

Yes.

Think of a direct short from 2 ends of a battery or two wires. The lower the resistance -> the closer to a direct short. Your receiver will keep trying to push out the power and over-heat.

4 ohm speakers are fine even on a receiver that says "8 ohms". But - you need to be careful to not turn the volume too-far up, and make sure you have lots of good venting around the receiver to help keep it cool.

 

[John Garcia]

Your Honda is going 120mph, but it is running at 16,0000 RPM to do it. In other words, that "extra" power isn't free, it still has a cost, and that is heat - more wear and tear on the receiver. You are also more likely to reach the limits of the amp more quickly, and the risk there is greater for your speakres than your receiver if you drive it to clipping.

A decent 8 Ohm receiver (90% of receivers are 8) will be able to handle 4 Ohm speakers, especially if it is only 2 out of your whole set vs all of them.

 

[Ted Lee]

i wish!

also, some receivers have an impedance switch in the back. i think they usually only go to 6ohms (?), and i'm not sure how well they really work ... but i guess it wouldn't hurt to put it at the 6 (or 4) ohm setting.

 

[John Garcia]

I've heard that using the switch on receivers that had one was not a good idea.

I had my Integra up to an indicated 138

 

[Ted Lee]

138?

best i ever did was about 120ish in my rx-7. tbh, i'm not quite sure because i was too afraid to take my eyes off the road and look at my speedometer. :b

 

[John Garcia]

My friend has a pic of his speedo pegged all the way over at 155 heading back from Sacto! (Supercharged Integra). I don't think I would have been able to take a pic of that...

 

[Brad E]

Well since we're already off topic. The fastest I've gone is and indicated 295 kph (around 181 mph, I think) on my Kawasaki ZX-12r.

I've tried many times to hit the speed limiter, which is supposed to be at 300kpm/186mph, but I either come up on a car or hill and have to back off.

 

[Ted Lee]

180 on a bike brad? man, you either got cajones the size of cantalopes or you just cuhh-razzzyyy!

 

[Brad E]

Well I've been called worse. I pick my spots carefully, long straight stretches, no approaches or intersections.

The bike is very stable at that speed.