ohms

[OldGrumpy]

still trying to get y head around a few things. I was looking at the salk songtowers, the specs note impedance of 4ohms nominal, 6 ohms average. I've read the technical explanations and I'm just not getting what it means form a practical perspective for my receiver. could someone explain this to me like I'm 5?

 

[Jeff R.]

In a very simpleton description and I am in no means an expert......the lower the ohms the lower the resistance of the speaker and in this case they are stating the that lowest resistance you will have across the speaker is 4 ohms and the average is 6 ohms. The resistance varies across a speaker at different frequencies. In general the lower the resistance or ohms the harder it is for an amplifier to power the speaker, however the speaker is generally more efficient due to the lower resistance. Most folks who are running 4 ohm speakers are either using external amplifiers or very high end receivers to handle this demand.

 

[PENG]

In general the lower the resistance or ohms the harder it is for an amplifier to power the speaker, however the speaker is generally more efficient due to the lower resistance.

You are correct except this part. Speakers with lower nominal impedance do not necessarily result in better efficiency and/or sensitivity at all. Just a side bar, for speakers, we typically should stick to impedance, not resistance.

 

[Jeff R.]

What is the difference? Are both not measured in ohms??

 

[OldGrumpy]

thanks. makes sense. I guess I should have asked the question behind the question as well - can an onkyo nr1009 run 4 ohm speakers? the specs confuse me a bit:

135 W + 135 W (8 ohms, 20 Hz-20 kHz, 0.08%, 2 channels driven, FTC)
160 W + 160 W (6 ohms, 1 kHz, 0.1%, 2 channels driven, FTC)

 

[PENG]

What is the difference? Are both not measured in ohms??

Impedance is a combination of resistance, inductive reactance, and capacitive impedance. Yes both are measured in ohms and Ohm's law applies to both.
I=V/R and I=V/Z where I is the current in ampere, V is the voltage in Volt, R is the resistance in ohms, and Z is the impedance in ohms. Speakers typically have much lower resistance value than it's impedance value. If you measure the resistance of an 8 ohm speaker with an ohmeter, the resistance could be less or much less than 4 ohms.

Again, both in ohms but Z is a complex number such that it's values is dependent on frequency. For further details just Google it as I don't think that's what the OP is looking for.

 

[PENG]

thanks. makes sense. I guess I should have asked the question behind the question as well - can an onkyo nr1009 run 4 ohm speakers? the specs confuse me a bit:

135 W + 135 W (8 ohms, 20 Hz-20 kHz, 0.08%, 2 channels driven, FTC)
160 W + 160 W (6 ohms, 1 kHz, 0.1%, 2 channels driven, FTC)

Depend on how loud you listen, dimensions of your room, and the sensitivity of your speakers. If you can provide such info, we can tell you for sure. As a generic response, I would just say that your Onkyo can run the L/R/C 4 ohm speakers of average sensitivity in a smaller to medium size room for people who don't want to risk damaging their hearing.

 

[OldGrumpy]

sounds like I'd be ok then. the room is about 20x30 feet, and I don't ever really blast it as it is an apartment building. I'm generally just looking for a good sound and I can afford to play around. I currently run a pair of polk rtia7 but I feel like they're a little unbalanced towards the high end. I'm looking at a few speakers - listened to the KEF Q500, would love to listen to a pair of salk songtowers but have yet to find a location to do that. still a little all over the place really.

 

[Swerd]

OldGrumpy

Although Salk SongTowers are rated at 4 ohms, they are an easily load for nearly any AV receiver including your Onkyo NR1009. In fact, Dennis Murphy and Jim Salk say that any receiver or amp that delivers at least an honest 50 watts per channel (when rated at 8 ohms at the full audio range of 20 to 20,000 Hz) can work with these speakers.

I've run mine with AVRs of 70 wpc, and heard them driven by 35 wpc tube amps. These speakers also do well with high powered amps, but they don't require them to sound good.

Where are you located? If you're near Washington DC, come hear mine.

 

[OldGrumpy]

ok thanks - let me check with the gf if brooklyn is near enough to DC.

 

[Swerd]

ok thanks - let me check with the gf if brooklyn is near enough to DC.

Ask Jim Salk if there is a SongTower owner in the NYC area who is willing to demo his speakers.

http://www.salksound.com/contact us.htm

 

[es347]

..Z varies with frequency