Axiom Home Page Forums General Discussion Home Theater No M80's for me

I agree with Johnk. If you look up the review of the 661 on audioholics.com, you will see that the 661 is a beefy 100w receiver delivering more than its stated power on a continuous basis.

When I was at Axiom, I had a chance to talk to Tom Cumberland about receivers. He told me that Yamaha (consumer side) tends to do a complete redesign of its amps with each new series, so it is hit and miss as to how good the amp section is. Denon, in contrast, tends to be more typically Japanese and makes incremental improvements to its amps with each new rev., so you have a great deal of consistancy.

Short answer, Brett has his heart in the right place, but is wrong on this particular Yamaha.

Sure, Fred; and an additional lab test on the 661 with comments is available from Sound&Vision . The report(note, 2 pages)indicates ample real-world power, including at 4 ohms, although certainly it and other similar receivers wouldn't be up to the over 1000 watt torture tests that Axiom ran on the M80s.

Well now I am a little p**sed to say the least, if in fact the Yamaha is ok to run the M80's I would have much preferred them first rather than the EP500.

As some of you pointed out in my other thread, speakers can make a big difference and the fact that they produce good base. I may have not even needed to get the EP500 at this point in time, I could have used the money and bought my receiver earlier.

Even if I wanted to swap them it would be too late for xmas

I thought we had already had you convinced to get the M80s awhile back, inspite of the Yamaha.

Too late already? Maybe a quick phone call could do the trick? You just purchased the 500, what, 2 days ago.

I thought so too.

Hi GraemeL,

All of us here at Axiom prefer to err on the side of caution in advising customers which brands of AV receivers will consistently work well with the 4-ohm M80s. The problem that has shown up consistently from customer experience with brands like Yamaha, Onkyo, and some Pioneers is that these brands will tend to prematurely shut down or go into severe current limiting when driving the 4-ohm M80s. The Denons, Sherwood Newcastles, Harman/Kardons, NADs, Rotels and a few others do not do this.

We can't possibly test all AV receivers with the 4-ohm M80s, but we have accumulated enough evidence from customers and in-house testing to suggest that certain brands may be problematic with low-impedance loads. So rather than risk disappointed customers, we simply recommend the brands we know work flawlessly driving the M80s to very loud levels without current limiting or shut-down.

As to Sound&Vision tests, you have to read the very fine print on the tests into 4-ohm loads. Some Onkyos have shown a consistent pattern of going into current limiting with 4-ohm loads, which reduces the power output dramatically. And you cannot rely on a test with one channel driven at a single frequency (1 kHz), the "standard" often quoted in some manufacturer's specifications.

Yes, your Yamaha may drive the 4-ohm M80s at reduced power output. But I'd rather you get a brand of AV receiver that we know will not give you any problems. That is what I advise Brent and the other audio experts at Axiom to tell customers.

Regards,

Alan

Hi,

Among AV receiver brands I do NOT recommend for the 4-ohm M80s, I forgot to include Sony.

And in recommended brands, I overlooked Outlaw Audio.

To follow up on reading the fine print in Sound&Vision tests, here are the results for the Yamaha 661:

Output at clipping (1 kHz into 8/4 ohms)
1 channel driven: 151/224 watts* (21.8/23.5 dBW)*
5 channels driven (8 ohms): 56 watts (17.5 dBW)
6 channels driven (8 ohms): 53 watts (17.2 dBW)
Distortion at 1 watt (THD+N, 1 kHz)

Note that the measurement is with one channel driven into 4 ohms and at a single frequency-- 1 kHz.

No measurement is stated for 5 channels driven, except at 8 ohms. The reason is that the Yamaha won't do it when you connect a pair of 4-ohm speakers and run it in the Dolby Digital 5.1-channel surround mode. It will drive 8-ohm speakers with five channels, albeit at reduced power output, and Dan Kumin, who used to write and review for me when I edited AV magazines, notes that in the text. And it will drive 4-ohm speakers in stereo.

Here is the asterisked comment on an Onkyo SR706 AV receiver in the 5.1-channel Dolby Digital mode tested by Dan for Sound&Vision:

"*Approximate result; with 5 or more channels driven the receiver protected, effectively shutting down, after approximately a half-second of drive at full output."

That is why I don't recommend the Onkyos for driving the 4-ohm M80s.

Regards,
Alan

I thought we were talking about yamaha?

He is talking about Yamaha, he just added a comment about the Onkyo at the end I believe.

Even if the Yamaha did shut down how hard would it have been to buy a pro amp ( cheap and powerful ) and use it to power the M80s as was suggested.