I have 2 speakers which I'm guessing are 6ohm rated as the receiver they came with is rated at 6ohms. My ohm meter measures all my speakers at the same ohm: measures 6.7ohms on all (8ohm, 4ohm, as well as these ?6ohm?).

The AV Receiver is measured at 8ohms. From HA searches, I should not connect speakers less than 8ohms.

How can I determine the ohm rating of these speakers?

If they are 6ohm speakers, can I connect them to the one "Center" channel output, by connecting the speakers together in series (vs parallel)? Sounds like this might become a 12ohm setup & therefore safe for the amp?

TIA

You can't measure speaker impedence with a normal ohmmeter. Ohmmeters measure the resistance, not the impedence of a speaker which tells you little or nothing about the impedence (which depends on the frequency. Google will be able to help you find the correct method for measuring speaker impedence.

You can connect your 6 ohm speakers in series. It won't be bad for the amp, but it will mean that each speaker will be 6dB quieter than it would have been if it was connected to it's own channel.

Infact there aren't really any standards for measuring the impedence of speakers. The problem is all manufacturers seem to do the averaging over freqency a different way.

Indeed. The impedence listed on a speaker is "nominal" which shoudl reflect the average impedence over the speaker's frequency response range. As chelgrin says, it's not that simple, as there are many many methods of doing this. Another complication is that in a complete speaker (rather than just a single driver) the impedence can vary by as much as an order of magnitude. Some popular designs can have an effective impedence of as little as 0.5ohms at their crossover point.

jkrelmore, do you have a spec sheet for that reciever? Most amplifiers designed for 8ohm loads will include a specification for max power into a 4 ohm load. If you are intending to use that much power or less into your 6 ohm load, all should be well.

THe Receiver specs state that the Center and Rear speakers must always be 8ohms. Otherwise there is a switch for connecting the mains to <8 >4ohm.

Taken literally: I should not use the 6ohm speakers for Center or Rear. I don't want to damage the amp.

I guess I'm shopping for a Center 70W matched with Rear 20Wx2 speakers.

KLH has good prices (KLH HTA-9706 5.1 100W for $60), but makes me have visions of my late 60's Realistic "integrated receiver/turntable" which was anything but...

I wouldn't be terribly concerned with connecting 6-ohm nominal speakers to a "8-ohm only" receiver. I've done it in the past. What you have to watch out for is heat and clipping. If the receiver is getting abnormally hot then the low impedance speakers are taxing it but if it doesn't get hot, then you should be OK. Also receivers that can't tolerate low impedance loads may clip at lower volumes so make sure you listen for that telltale clipping sound before cranking up your system.

I have Onkyo receiver that is suitable for 6-ohm speakers. However, I have it connected to a pair of speakers that are 8-ohm nominal and 3.8-ohm minimal. I haven't encountered any problems. Low impedance in and out of itself is not necessarily a "baddie" because you also have to consider phase angle and what frequency is associated with the lowest impedance.

Solution follow-up:

Those 6ohm speakers are no where near the 70W required.
Due to space constraints on a Center Channel speaker I will install 2 - 4 1/2" 12ohm midrange speakers into my entertainment center/cabinet & parallel them to the center channel, add a 2ohm non-inductive resistor to present 8ohms to the amp. VIFA BC11SG06-12 4-1/2" JBL MIDBASS SHIELDED 12 OHM

With "buyout" prices this nets to $27 from partsexpress (great tech advice).

The resistors are <$2. So for those of you worried about running low ohm speakers on your 8ohm amp, this is an easy fix.