Axiom Home Page Forums General Discussion Technical Questions 6ohms or 8ohms?

I can see the person at Yamaha saying this but it seems odd that a person from Axiom would.

Han, as other replies have indicated, you should only use a lower than 8 ohm setting as a last resort in the highly unlikely circumstance that your receiver would shut down at the 8 ohm setting. Otherwise you'd simply be voluntarily limiting the maximum voltage(and therefore power, which the voltage controls because of Ohm's law)which the receiver could supply. Disregard any advice to the contrary, which may possibly be motivated for legal rather than real technological reasons.

I agree Bren, I've never heard any of the Axiom main techs like Alan, Tom, or even Ian suggest the 6 ohm position. I'm guessing they misunderstood Han's question.

I know at least 3 of my friends with Yammy's that were told by Yammy tech support they could use the lower settings when lower ohm rated speakers were in the loop, not a good thing when the other speakers aren't rated for this resistance.

Hi, BrenR:

I don't remember whom I talked to at that time. I did talk to the Axiom person before I was about to buy the Yamaha RX-V2600 .

Thank you guys. I just reset my Yamaha reciever to 8 ohm. It is always a pleasure to communicate with you guys.

Good night,

Han

Hi Thanwu,

Odd indeed. No-one at Axiom should be telling you to set your Yamaha at a 6-ohm setting. I'll have to do some internal detective work!

This has been a continuing issue with various brands of AV receivers for years because of the 4-ohm M80ti towers, which many brands will not drive without overheating, current limiting or protection-circuitry shut-down. As Bren pointed out, the presence of an impedance-selector switch suggests that the AV receiver has limiting circuitry that will severely limit the power output to lower impedances to avoid liability and overheating issues. Leave the switch at the 8-ohm setting to maximize the receiver's potential output into 6-ohm and 8-ohm loads.

Axiom has been advising this for years now.

Regards,

Hi, Alan:

It is possible I misunderstood when I talked to the Axiom tech support. No need to do your detective work. I am very happy with the service you company provided to customer. One more question. In terms of my setup: M60tis and VP150, do you have a rouge guide how much ajustment I need to make manually for my center speaker because the 8ohm setting?

Thanks,

Han

Hi,

The impedance rating of the speaker and the setting of your Yamaha do not relate directly to the level settings for each channel.

Just go through the normal calibration for each channel. Use a Radio Shack SPL meter and a setup DVD and do a manual adjustment of each channel's level from your seating area.

Other than just leaving your Yamaha at the 8-ohm setting, there are no special adjustments required for using a group of speakers of different impedances. Each speaker or channel is driven by a separate amplifier in your receiver, so the impedances do not interact with each other.

Regards,

That raises an interesting question. When Axiom (and others) publish sensitivity ratings (typically SPL at 1 watt, 1 meter from the speaker) is that really 1 watt (measuring voltage and current) or is that "the voltage which corresponds to 1 watt into an 8 ohm resistive load" ?

In other words, does it take into account the fact that a 4 or 6 ohm speaker will draw slightly more power at the same volume control setting ?

Hmm... now THERE's some internal detective work

I would think the resistance is taken into to account when measuring for specs, one watt at one meter @ four or six ohm.