Axiom Home Page Forums General Discussion Advice from Axiom Owners A couple of receiver questions...

I've heard bad things about the Onkyos. Such as overheating issues and problems with the the video scaling. ( i.e. forced 4:3 on 480i sources and downscaling of 1080p over component)

It was enough to make me look elsewhere which I became interested in the Marantz. I've heard they have good audiophile cred and they don't have an on board video scaling chip which I prefer.

I know a not too ol boy who connected his M80s to his wife's 2.2W boombox and listeners couldn't tell the difference between that and his Denon :D.

I don't know what the equation is. I know that there are on-line calculators that try to tell you but I haven't spent enough time to determine whether they can be trusted.

But to answer your question, if you are satisfied with 73 to 85dB in your 3,000 cubic foot room at 8 feet away, then a 90W/channel amp should do you just fine. You're planning on 60s vs. my 80s (which are more sensitive) but based on recent testing that jakewash and I did, the sensitivity of the 60s is pretty darned close to the 80s.

I'm thinking that old boy should have rid himself of that high dollar Denon and kept the 2.2W boombox to power up them Axiom 80v2 floorstanders .... just a waste of money if'n you ask me!

Now that is a good one Rick. If there is no difference why the heck not.

Sure. Peaks would definitely draw more. Some music may require 18dB peaks which would mean 32W with a half watt nominal. So even if you listen at nominal levels of 1 W/channel, 18dB peaks would require 64W. That still leaves you ample room with a 90W/channel amp.

If you know the speaker SPL at a specified distance with a specified power, you can estimate the SPL at any distance and any power. The M22 for example has a sensitivity of 89dB/W/3 feet. At 9 feet, the SPL is 83dB. Two M22s would give rise to 86dB. Since you are reporting 75dB, most likely your amp is sourcing less than 1 Watt. I say most likely because there are room effects too.

I've measured the power into my M80s at 50Hz and I also know exactly where my Denon starts to distort and where it starts to square-wave. Look for my post titled something to the effect of power into my M80s from my cheap Denon. I've figured that I listen to music at about a half watt nominal and movies at a few watts.

Good for you for trying to understand this yourself practically rather than just reading articles.

And yes, you definitely need more than half a watt because there are peaks that must be accounted for. 90W should be adequate based on what you consider loud. I would say that if you listen to neo-classical, you may need 200W/channel. I have 90W and it is barely enough for some classical if I really want to make my 'nads shiver. However, since I don't listen to classical very often, I am not rushing out to get a new amp. 90W for me is over-kill for 99.9% of my needs.

Priz, a couple of things that you mention that you're "sure" of are highly unlikely. First, if your present Sony is rated at 110 watts per channel, you can be confident that it would actually deliver that at maximum output. As we discussed earlier this year, that rating has to be met in a lab test(no home audio use is this severe)for at least five minutes continuously under FTC regulations which apply to all receivers sold in the U.S. Failing to meet the advertised power rating would be a violation of the law and manufacturers aren't foolish enough to do it. This is confirmed by AV magazine lab tests on the units in question.

Next, if your Sony is operating within its designed power limits it's amplifying the entire audible frequency flat and with inaudibly low noise and distortion. This is all that any amplifier can do(sound processing is a separate matter)and there's no good reason to expect better sound from the Marantz unit.

As to the power ratings involved, keep in mind that at a comfortably loud average listening level your speakers will be using no more than about 1 watt. Brief peaks use much more, of course, depending on how wide the dynamic range of the material being played is. The difference between 80 watts and 110 watts is only about 1.4 dB in maximum sound level possible at peaks, for example 106.4 dB compared to 105 dB. It's unlikely that the difference would be significant in your use, so if the 4002 has the features that you want, you shouldn't hesitate because of the power rating. I'd agree however that the the new Onkyo 705 would be an excellent candidate and should be considered.

Actually Rick, I could get away with the boombox for most music but it definitely doesn't cut it with movies. And I do like to crank it up from time to time :). I would never, ever recommend anyone buy a 2.3W/channel amp.

Randy, they couldn't tell the difference at a half watt per channel. A "distortion-free" watt is a watt no matter what amp it comes from.