ohms not showing (1 Viewer)

[sheldon-VIC]

hey all,
i recently bought a surround package buy nuance and i am having problems with the rear speakers. they are working but my ohms tester doesn't register them, is this bad or normal. i ask the places around my place, knowledge is very limited due to isolation, and i get all different answers. from ..... it's normal for rears to not show..... to your speakers are pooched. can someone please give me answers?

thx in advance
VIC

 

[Khoa Tran]

Please do a search on nuance on this forum....

 

[Justin=>]

Yes, please do some research on nuance before you decide to keep them for the long run. Check out the forums or goto epinions.com. I think you will be suprised on what you will find.

 

[sheldon-VIC]

unfortunatly i am stuck with these for a long time, thx for reminding me that i got suckered. now could you plz answer my question, is the fact that they don't register a bad thing.

thx
VIC

 

[JerryCulp]

Doesnt show as in they show a open or a short?
I cant imagine that either way it would be good, but a dead short would probably trip the amp.

 

[Chu Gai]

Remove the wires from the speakers and attach the leads from the multimeter to the speaker terminals. Make sure your VOM is set to read resistance and not voltage or current. If your multimeter isn't auto-scaling you ought to set it so that it can read resistances like 8 ohms.

 

[Michael R Price]

What if there was some big capacitor in series with the woofer to limit bandwidth... [Why would anyone do this anyway?]

 

[PaulDF]

Can I ask why you are measuring the resistance of your rear speakers, if they are working? What problems are you having?

 

[MingL]

The 8/4ohms impedance is not measured using a multimeter.

Whats the deal with measuring resistance?

 

[sheldon-VIC]

i wanted to find out the ohms because i was looking at getting a new reciever. i'm currently running the sony 935, that is only good for 8 ohms. i was told that because it is 8 ohms only, and my speakers are less, that i could fry my reciever. so i was looking at getting a harman kardon, either the avr325-330 or the dpr 1001. they will do to 4 ohms, or i heard the yamaha will do to 2 ohms.

if a meter is not the right way, then how do you find the ohms, i can't find any info on them?

thx for the feedback
VIC

 

[Brian Fellmeth]

You can measure the resistance of your speakers with a multimeter. You will get the DC resistance of the unit which is typically about 75% of the nominal impedance. Expect to measure about 6 ohms for an "8 ohm" speaker, and about 3 ohms for a "4 ohm" speaker. As suggested above, set the meter for its lowest resistance range and calibrate the meter by making sure it reads zero ohms when the meter leads touch.

 

[Bob McElfresh]

The 8/4ohms impedance is not measured using a multimeter.

Whats the deal with measuring resistance?

You cant do this.

A speaker has "Impedence", not DC Resistance.

If you just hook an ohm meter to a driver you will read zero ohms. The two wires are simply 1 long wire coiled up. It has very little resistance to a DC current which is what you are measureing with an ohm meter.

But that wire is coiled. Something very strange happens when you FIRST apply some current. The current does not flow at first. Some of the energy is spent creating a magnetic field in the coil.

(Remember those old experiements with a compass and a loop of wire and a battery. Wrap the wire 20-30 times around the compass and connect the battery and the compass needle will swing to a new position? Thats because of the magnetic field around the coil of wire.)

Once the magnetic field is established for a constant voltage/current, then whatever goes in one end comes out the other just like a straight piece of wire.

But what if we suddenly changed the voltage or current? If we increased the voltage, some energy would be used up as the magnetic field grows. If we decreased the voltage, we would actually not see the change right away as the magnetic field would reduce and supply energy back to the wires.

The trick with a speaker is we keep changing the voltage & current thousands of times per second. The energy that is lost with growing/shrinking the magnetic field is just like the energy that is lost running a constant current through a resistor. So they give it the same units: Ohms.

And it gets worse:

A speaker has a "Nominal" impedence. But in fact, the impedence of your speaker depends on the frequency of the sound you are passing to it. For example, a 8 ohm speaker speaker could have:

2 ohms impedence at 30 hz
3 ohms impedence at 90 hz
4 ohms impedence at 400 hz
5 ohms impedence at 900 hz
...


This is why you cannot simply hook up a ohm meter to a speaker and obtain the impedence.

Yes, some speakers do show resistance with an ohm meter. As Brian pointed out you can assume you are seeing ~75% of the impedence.

A speaker has a small circuit called a "Crossover". You are seeing some resistance because of this circuit.

Does this help?

 

[Michael R Price]

No, the woofer does have a certain DC resistance that is measurable by a multimeter. This resistance is always some fraction of the nominal impedance (it's 2.6 ohms for my 4 ohm speakers). If your speakers are a short circuit at DC, something probably went wrong. Of course, if you are measuring speakers connected to an amplifier and you will also be measuring the resistance of the amplifier output circuit which could be very low.

 

[Robert AG]

A speaker voice coil WILL have a DC resistance, and as posted above, it will be around 6 ohms for an 8 ohm speaker and 3 ohms for a 4 ohm speaker. Under use, the IMPEDANCE will vary with frequency depending on several factors like the box, the speaker etc.

Actual measurements with a multimeter will measure the woofer's DC resistance along with the resistance of the inductor in series with the woofer, if there is one. That inductor will have resistance of a fraction of a ohm.

There might be other things in the speaker like L-pads which will alter the DC reading. If for some reason there is a capacitor in series with the whole speaker, there will be an open circuit as far as DC measurements are concerned (at least until the capacitor charges up).

 

[PaulDF]

Sheldon, as far as I knew, All Nuance are rated at 6 ohm. Though this is debatable since Nuance doesn't feel it is necessary to list virtually ANY other specifications on their speakers. A lot of people seem to run them no problem with their 8-16 ohm capable receiver. You may as well use your current receiver for now, and when you want to upgrade, look at 4 ohm capable receivers.

 

[sheldon-VIC]

i wrote to nuance and they said they were between 4-6 ohms. they also told me my wattage and stuff, if anyone wants to know what they are (if you also got suckered) i will give you the info.

thx for the input folks
VIC

 

[PaulDF]

I would be very interested in any specs Nuance shared with you.

To this day, these speakers fascinate me. Not because of the speakers themselves, but because they are very different with their marketing strategy. And a lot of people who own them seem to really like them. (Though they'll rarely admit it here!!)

In my opinion, the Nuance speakers I've encountered do have a few things going for them. The cabinets are rock solid, and they can take a beating. From what I've heard, the sound is pretty clear, and the frequency response dips down quite flat into the 30's with a single 6" driver. I have no experience with the power towers, except for brief demos instore, and from talking with friends. Though they are said to go quite loud, and with a lot of bass. The sound quality at that level is not yet determined...

If only Nuance charged 1/4 to 1/3 the price these might be something to look into. But you gotta give them credit, they have sold countless multi-thousand dollar speaker pairs. And at least some of those people are very happy. Now if only that one "happy" guy I know would buy that center channel I want to sell!

Oh, and before you forget, Sheldon, I really want to know those specs... Thanks

Paul