Jump to content
HAL9000

Klipsch speaker impedance ratings

Recommended Posts

I just bought a couple of used Klipsch KG .5 bookshelf speakers (rating Impedance 8 ohms). I measured the resistance and I got 3.8 ohms. I thought something was wrong with these speakers. I know that Impedance rating is not the same as the resistance measured with an ohmmeter, but my understanding is that, normally, that reading would be about 2/3  to 3/4 of the speaker impedance rating (all my other speaker's rated 8 ohms their resistances varies between 6 and 7 ohms).

 

So I measured the resistance of my other Klipsch bookshelf speakers, two SB2's rated also at 8 ohms (which I bought new but I did not use much). To my surprise, their resistances were 3.8 ohms. My questions is, why for the same impedance rating, Klipsch speakers differ so much from my other speakers (and from the general rule)?  Are they 8 ohms or, in reality, just 4 ohms? should I be concerned about my amplifier (set at 8 ohms) using these speakers? Thanks.

Share this post


Link to post
Share on other sites

Fwiw, I have a small 18w Pioneer amp that I beat up on all the time. It has a protection circuit that kicks in when the volume is at about 50%, depending on the content being played. I assume the 50% mark is where all 18 watts are delivered and anything above that is just compressed.

Anyway, I've owned dozens of klipsch models(including KG .5) and they all trip the protection at same level as other 8 ohm models from Polk, Pioneer, Sony, etc...

If I wire two pairs of speakers in parallel(4 ohm), the circuit will trip at about 30%.

So I've concluded that Klipsch speakers are no harder on the amp than any other models. And, due to their efficient nature, probably even less worrisome.

Not the most elegant way to test, but there you have it.

Share this post


Link to post
Share on other sites

The 8 ohm rating is a nominal value or average.  It's not unusual for a speaker to swing widely.  Speaker impedance is the resistance the speaker gives to the current and voltage.  There is a good chance if you are using a sub, you will never see the lowest impedance(highest resistance).

Share this post


Link to post
Share on other sites

I just bought a couple of used Klipsch KG .5 bookshelf speakers (rating Impedance 8 ohms). I measured the resistance and I got 3.8 ohms. I thought something was wrong with these speakers. I know that Impedance rating is not the same as the resistance measured with an ohmmeter, but my understanding is that, normally, that reading would be about 2/3  to 3/4 of the speaker impedance rating (all my other speaker's rated 8 ohms their resistances varies between 6 and 7 ohms).

 

So I measured the resistance of my other Klipsch bookshelf speakers, two SB2's rated also at 8 ohms (which I bought new but I did not use much). To my surprise, their resistances were 3.8 ohms. My questions is, why for the same impedance rating, Klipsch speakers differ so much from my other speakers (and from the general rule)?  Are they 8 ohms or, in reality, just 4 ohms? should I be concerned about my amplifier (set at 8 ohms) using these speakers? Thanks.

Impedance is not the same as resistance.  Impedance varies with frequency (frequency dependent) and is nominal or averaged across the frequency range.  When you measure with an ohm meter, you are getting DC resistance, no frequency.  Due to things like inductors that can look as though they are almost a dead short, using an ohm meter can just give you a relative value for comparison between two speakers, or be used to check if a driver is likely good when pulled from a circuit.

Share this post


Link to post
Share on other sites

... Speaker impedance is the resistance the speaker gives to the current and voltage. There is a good chance if you are using a sub, you will never see the lowest impedance (highest resistance).

That's backwards; the lower impedance has lower resistance, and higher impedance has higher resistance.

"Impedance is the electrical characteristic of a speaker that restricts ("impedes") the flow of power from your receiver or amplifier. Impedance is the combination of the resistance of a speaker plus its reactance."

  • Like 1

Share this post


Link to post
Share on other sites

I'm a new forum member but I've been a hardcore Klipsch believer, buyer, & owner, since I heard their Cornwall’s for the first time back in 1980! I’ve recently starting building a modest version of a stereo component system, (very modest), similar to what I used to have when I was an audiophile, (1979 to 1990). In the past year or so, I've been buying and cleaning up some vintage components and the integrated amp I am now using is a Sansui A1200.

 

It's not one of Sansui's best of course, but it's pretty good and was under-rated 'back in the day'. It'll be a long while, I'm afraid, before I can convince my wife to let me buy a McIntosh so for now, I'm holding at that position.

 

Anyway, that's my very condensed ‘self-introduction’ to the forum. I’m sure this forum will prove to be very beneficial in refreshing my memory and bringing me up to date on ‘stereo-physics’, (in fact, it already has). 

 

I presently have a pair of Klipsch RB3 (Maple), and another pair of Onkyos. In addition, I recently, (like, last week), added a new Polk Audio PSW-10 Subwoofer.

I just received an OSD-SSVC6D Stereo Speaker Selector and I was working out the way I wanted to wire the speakers in addition to working in the sub while I was at it. 

 

I'm considering a Parallel wiring method so I pulled out the DVMM and was surprised to find the 8 Ohm Klipsch were reading 3.8 Ohms! Like the thread starter, I thought I broke something because my 8 Ohm Onkyos read 7.6 Ohms, ergo...

 

However, after reading this thread, (which I found very quickly when I ran a search), I’m relieved to find that I’ve been making the mistake of considering impedance and resistance to be one in the same. “Relieved” because the other explanations included the possibility that I did break something.

 

I have several hobbies and among them is microelectronics. I’m surprised that I didn’t realize that fact, (impedance and resistance differences), before now! However, it’s in my learning curve and that’s always better than ‘flat-lining’!

Thanks to all for clearing that up!
Rich
 

Share this post


Link to post
Share on other sites

It certainly can swing across the working frequency range of the speaker.

Take for example my RF7 MK2's, the BLACK curve is the impedance .... you can see the lowest impedance is about 3.5 Ohm or so which is reach around 150Hz or so.

At that frequency, the RF7-II gives your amplifier a good workout since it will the amp draw the highest current across its working freq-range.

 

 

Klipsch_RF7_II_Impedence_Curve.jpg

 

Share this post


Link to post
Share on other sites
51 minutes ago, jvanhambelgium said:

It certainly can swing across the working frequency range of the speaker.

Take for example my RF7 MK2's, the BLACK curve is the impedance .... you can see the lowest impedance is about 3.5 Ohm or so which is reach around 150Hz or so.

At that frequency, the RF7-II gives your amplifier a good workout since it will the amp draw the highest current across its working freq-range.

 

 

Klipsch_RF7_II_Impedence_Curve.jpg

 

I have seen this graph on AVS and if I remember correctly you actually customized your RF-7IIs? If they were yours they looked awesome

Share this post


Link to post
Share on other sites
22 hours ago, Zen Traveler said:

I have seen this graph on AVS and if I remember correctly you actually customized your RF-7IIs? If they were yours they looked awesome

Hi,

Nope, not me I guess.

I'm running standard RF7-II"s , but paired to a set of 2 * SVS PB13 Ultra subwoofers and an Audyssey "Pro" calibration on top of this all.

Can't say it sounds bad :D:D

Share this post


Link to post
Share on other sites

I'm hoping it is OK if I add a question to this, as I'm a newbie to all the technical aspects.  And I have tried to find out, but I'm not really understanding it.

 

I can understand that speakers are rated 8Ω or 4Ω, although the actual number varies and is frequency dependent, and that somehow if you connect two 8Ω speakers in parallel you get 4Ω.  My daughter even did a science experiment where she showed the output of the light was brighter when two wires were connected from the battery to the light in parallel, so I'm thinking I might understand this aspect.

 

So, if there are two speakers, and one is 8Ω, 99dB and one is 4Ω, 99dB, the 4Ω speaker will use the power supplied to it more efficiently to put out the same volume (dB)?

 

If one speaker was 8Ω, 99dB and the other was 4Ω, what dB rating would equal the 8Ω speaker for equal power supplied to each?  Or maybe if I say you put enough power to make the 8Ω speaker produce 99dB, what db output would the 4Ω speaker be at the same power input?  Why isn't there a "dB / watt input" rating in addition to all the other specs, isn't that what people want to know?

 

I somewhat understand that a given amp only has so much power to output, but then why isn't everybody trying to get 4Ω speakers that use it most efficiently?

 

On 7/2/2016 at 11:42 PM, mattSER said:

Fwiw, I have a small 18w Pioneer amp that I beat up on all the time. It has a protection circuit that kicks in when the volume is at about 50%, depending on the content being played. I assume the 50% mark is where all 18 watts are delivered and anything above that is just compressed.

Anyway, I've owned dozens of klipsch models(including KG .5) and they all trip the protection at same level as other 8 ohm models from Polk, Pioneer, Sony, etc...

If I wire two pairs of speakers in parallel(4 ohm), the circuit will trip at about 30%.

 

And for that 18w amp, isn't the 18w producing more dB at just the 30% level than the 8Ω speakers at 50% level?

 

Or am I just completely mixed up?  (And if the answer is yes, I'm hoping it can be explained why as I'd like to learn.)

 

Share this post


Link to post
Share on other sites

@ksquared  If you have a 4 ohm and 8 ohm speaker and both are rated to produce 99dB at 1 watt at 1 meter then both are using that 1 watt of power at the same efficiency. The 4 ohm speaker requires more current and less voltage than the 8 ohm speaker to dissipate the 1 watt.

Share this post


Link to post
Share on other sites
6 minutes ago, babadono said:

@ksquared  If you have a 4 ohm and 8 ohm speaker and both are rated to produce 99dB at 1 watt at 1 meter then both are using that 1 watt of power at the same efficiency. 

OK, this part I now understand too.  Give a speaker 1 watt of power, if 99dB come out, they're both using the power at the same efficiency.  That makes perfect sense, and it doesn't matter what the impedance of the speaker is.

 

7 minutes ago, babadono said:

The 4 ohm speaker requires more current and less voltage than the 8 ohm speaker to dissipate the 1 watt.

And here's where I derail.  Why? 

 

But, this then makes it more understandable that an amp gives out, I'm guessing it can't output the higher current required.  The 8Ω speaker takes the power (current) at a slower rate?

Share this post


Link to post
Share on other sites
6 minutes ago, ksquared said:

The 8Ω speaker takes the power (current) at a slower rate?

Ha, Ha LOL  I'm sorry but that there is funny. But seriously the lower the impedance the less restriction to current flow for a given voltage. And yes you are correct some amplifiers(although rare nowadays) cannot put out the current required of a 4 ohm speaker.

Share this post


Link to post
Share on other sites
16 minutes ago, ksquared said:

The 8Ω speaker takes the power (current) at a slower rate?

 

1 minute ago, babadono said:

Ha, Ha LOL  I'm sorry but that there is funny. But seriously the lower the impedance the less restriction to current flow for a given voltage.

 

Now, I told you I'd already derailed. :unsure:

 

Would it be technically better to say the higher impedance speaker needs the power (current) at a lower rate?  But, given the previous requirements, it would need a higher voltage?

 

Share this post


Link to post
Share on other sites

The higher impedance speaker needs a higher magnitude of voltage and a lesser magnitude of current for a given wattage. What I thought was funny was your use of the word "rate" as if we're speeding up or slowing down the flow of electricity. I'm sorry if I offended you.

Share this post


Link to post
Share on other sites
53 minutes ago, babadono said:

@ksquared  If you have a 4 ohm and 8 ohm speaker and both are rated to produce 99dB at 1 watt at 1 meter then both are using that 1 watt of power at the same efficiency. The 4 ohm speaker requires more current and less voltage than the 8 ohm speaker to dissipate the 1 watt.


I even went to electrical engineering school and can't totally understand this aspect.  It's easier to look at the Acoustic Elegance site for an example.  1 watt and they're both the same, but give it 2.83 volts and you'll see that the 8 ohm one is about 3 db lower due to getting half the current.  Some people would say that the 8 ohm driver is actually twice as efficient in this situation.  Sounds weird but look at the big jump in motor force.  Why is that if they're the same?  

  • Like 1

Share this post


Link to post
Share on other sites
Just now, babadono said:

What I thought was funny was your use of the word "rate" as if we're speeding up or slowing down the flow of electricity. I'm sorry if I offended you.

 

No, no offense meant by you nor taken by me. :)

 

I appreciate the help to understand it.

 

Share this post


Link to post
Share on other sites
Just now, MetropolisLakeOutfitters said:

I even went to electrical engineering school and can't totally understand this aspect. 

 

Now Cory knows how to make a newbie feel better. 

 

Share this post


Link to post
Share on other sites

Disclaimer: I am not a speaker expert. But my understanding is this. A speaker is a transducer, it changes one form of energy to another. In this case electrical energy to acoustic energy. So if two speakers produce the same acoustic energy output given the same electrical energy input they have the same efficiency. Where am I going wrong?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×