Axiom Home Page Forums General Discussion Technical Questions how has onkyo 609 and M80?

Nikon, I haven't heard of anyone having issues with 8 ohm QS8's and M80's up front(as I have). I'm running M80's, VP150 and QS8's which are rated at 4 ohm, 6 ohm, and 8 ohm respectively, through a mid level Denon. I know there's a few guys here with Onkyos and similar setups, and fancier. I haven't heard of any issues reg mixing ohms, but hopefully those owners can chime in at some point.

NikonShooter,

Those articles have all the relevant information for this discussion.

Impedance is not constant on a loudspeaker. It varies with frequency. So when you start to hook up two different models of speakers (even if they are the same brand) you will be mixing impedances at pretty much all frequencies. The rated impedance of a speaker by a manufacturer if its 4, 6 or 8 ohms means pretty much nothing.

To get an understanding how well a particular receiver will play with a speaker you would need to know the impedance and corresponding phase angle at each frequency. Speaker efficiency is another key factor, listening distance and SPL all matter too.

Well, I contacted Axiom and they couldn't help me. That was the very first thing I did. So, if they've said it here on this forum, I'd appreciate it if you'd direct me to just exactly where that is. Second, I don't think it would be very practical to use M80's for all channels now, do you? Surely you're not serious. I've got a big AV room ... but not that big. (I'd say there might be some audio problems associated with turning an M80 on it's side to use as a center channel speaker, too. ) That's one of the reasons I wanted to swap out the Infinity's in the first place. Third, just because you have never once heard of a receiver or speakers being damaged by mixing impedance, doesn't mean it hasn't happened. Indeed, for most folks maybe discretion has been the better part of valor. Fourth, it is incorrect for you to assume that I'm not inclined to listen to what you perceive as non-experts on the internet. As I already mentioned to you, I wasn't looking for advice. I was simply stating what I had found out from Onkyo (not Axiom) as I was trying to decide on the M80's. And that was posted here on this forum to perhaps help the original poster in some way.

That being said, show me someone who has been doing what I describe, with the Onkyo TX-N5009 ... doing it for some time with no problems whatsoever ... and Axiom just might sell another pair of M80's.

Well, it really doesn't you know. And,I'm well aware that impedence is variable over the course of the audio material being presented.

When it comes to receivers, it is high current(low impedance) demands that can potentially put AVR's into protection mode. So if anything adding multiple speakers rated the same at 4 ohms could be potentially problematic over one set of speakers rated at 4 ohm and one rated at 8 ohm.

If you want to limit the power capability of your Onkyo and play it paranoidsafe, please go ahead and set the switch as Onkyo recommended.

It's actually the opposite. The most likely scenario that could cause shutdown and overheating issues would be to hook up all 4 ohm speakers to that Onkyo. Even then it would be still dependent on how efficient the speakers are, the SPL at the listening distance, the source material being used and how long high SPL's are sustained.

He was giving advice not wanting it from what I gather.

Just FYI, I have heard a setup with 5 M80s, 2 QS8s and an EP600. It was rather staggering. Dude was powering it with 5 Parasound amps, as I recall.

That said, he was having shutdown issues originally (with Outlaw amps) because of how loud it was (>115dB) and the fact he was running 5 4 ohm speakers, not because he mixed 4 and 6 ohm.

Shooter, welcome. The response you got from the Onkyo rep is total nonsense. He apparently was trying to interpret what the manual suggested, but he had no understanding of the technology involved. If there was a problem with using speakers with different impedance ratings simultaneously(there isn't)using 4 ohm with 8 ohm would be less of a problem than using 4 ohm with 6 ohm. The point is that the overall net impedance, taking all the speakers into account, determines the amount of current used at a given volume level.

There are no problems with lesser units than your 5009, and you certainly should experience none. In any case, keep the impedance setting at the default higher number, since setting the lower one simply restricts the amount of voltage available from the receiver's power supply section. This results in limiting current and power available(following Ohm's Law)and reduces the chance of overheating, but at the expense of limiting maximum performance capability(tests show that the lower setting cuts maximum power output roughly in half).