Axiom Home Page Forums General Discussion Home Theater How much power do I need - m60 measurements

Thanks John, great article, once again I'm amazed by your ability to get relevant advice on any subject. It makes me wonder if you and Gena had offspring what the results would be

I've always been curious what speakers JohnK actually owns? I heard a nasty rumor he was a BOSE guy.

Hey Gena!
Very cool post! I'm mostly ignorant about such things but have a few questions (mostly to prove that I didn't just skim your post!!!):

--I assume the fluke connects between the amps' outputs and the speakers themselves? Does the resistance/Ohm rating figure into this as to what a speaker actually draws?

--How fast does the Fluke respond to peaks? I'm curious about those very fast, very short transients.

--Did you re-meter the Floyd music tests with the RatShack SPL meter or base the peak levels on the previous sine-wave readings?

--In another post, you alluded that adding an external amp to a receiver would double the possibility of distortion (I'm paraphrasing). Why would that be the case? The signal is still going through one preamp (the receiver's) and one final amp stage (auxiliary amp).

I don't know enough to agree/disagree on this topic. Mostly, I have a tendency to agree that there wouldn't be a difference in well-designed, reasonably-powered amps. I'm 90% committed to that.

But......
For years, I did own a NAD 2200PE, which (according to the marketing) was designed as a 100 WPC amp in continuous mode but with high power (if I remember correctly, 400 watts for short-term of 10 seconds or so) and enormous capability for short peaks and transients in the area of 1200 watts. Maybe I succumbed to the marketing, but I would swear that a good, dynamic recording such as a Billy Cobham drum solo just sounded much more "real", which I wholly attributed to the reproduction of the transients. Of course, that was 15-20 years ago, and I sold them to buy a cheap Technics surround receiver (because I didn't spend any time listening to music anymore) and wanted multi-channel capability for my video collection. So maybe I just remember the whole thing as going from "separates to a Circuit City special" and was so biased as to not really hear the differences….

God, I DO miss that "Pride of Ownership" of those three NAD separates though. Much as I like my Denon 3805, it's really not the same!

If the M60s where 8 ohm across the board this test would seem correct. As we all know there is not a speaker made that has a straight across the board omh rating. Not to invailidate the test but how can it be accurrate when the fluctuatoin of resistance is not takin into affect.

I must admit that until recently, 'upgraditus' had been starting to take hold regarding the purchase of an additional 2-channel amp/seperates to hopefully 'improve' SQ even at lower volume levels (especially bass), as a majority of people who have upgraded have stated.

After extensively reading posts regarding this very subjective issue, I found myself gradually shifting to a more pragmatic approach, leaving myself open to the possibility that my mind may play a large role in SQ perception in terms of possible improvement upon what I already own.

After reading JohnK's posted article, it just plain makes more sense to me. In my opinion, the only reason to upgrade to a more powerful (at least twice the power) amplifier is to fill a much larger room with louder sound. I won't get better imaging, clearer mids, more dynamics, or better bass at low volume levels. I've got an EP500 helping out down there anyway! Speaker selection and room acoustics play the largest role in sound reproduction. It isn't my intention to upset anyone who believes otherwise... I'm just sharing my own conclusion.

While what Alan says about the specifications between a receiver and a pre/ pro may be true in some cases, I have to wonder if anyone can hear the differences???? When you are talking about THD numbers (differences) of less than .01-.04%, who can hear the difference. Same goes for other specifications.

We have discussed, on other threads, that the MAIN difference between receivers and most pre/pros with seperate amps is the design of the power supplies. So, once again, we are back to how much power do you really need on a per channel basis for your listening pleasure in your home?

I just don't think that we will get a consistent answer to that question.

Mark, thanks for time reading the post.

About the Fluke meter. It allows to capture short peaks, down to 250 microseconds (it’s one period of 4 kHz tone). While by no means it is as fast as a scope, I thought it was good enough for practical purposes. The Fluke was connected right to the speaker’s posts, and the 8 Ohms constant resistance was assumed for power calculation. The SPL was measured for both single tone and music tests.

By no means a 100% accurate test, I think it correctly captures some very practical moments. One of which is it takes less than 1W of average power per main channel to listen at my threshold of loudness. I agree, it’s personal, and some people might like it much louder. At the same level the peaks reach at about 10W or so which is still much less than the dynamic power of the receiver.

As far as comparing the sound quality from a distant memory…. I think JohnK already alluded that only a carefully designed double blind test can prove or disprove that. Other than that it’s only on the personal level of perception.

But, here is a thing. There are trade-offs. My other hobby is photography. You’d be surprised how many people buy ten’s of thousand dollars worth of equipment and then spend all their time taking pictures of brick walls, comparing the sharpness of this to that, resolution of this to that… No money left over to make good prints or travel to photographic locations.

I can afford a $2,000 amp. But the same money can get me a bunch of DVDs and CD’s and a few tickets to good concerts. I’d rather do that then succumbing to a questionable sound improvement. But, it’s me, everybody’s mileage is different.

Nice post......I have a question.
I don't recall seeing a mention, about THD specs in the thread. ( I hope I didn't miss it).
For me, the THD info tells one if the "amp" can indeed, provide clean power...especially at higher listening levels...(if the figure is legit. of course).
Where am I going wrong?........perhaps someone could address this for me, even the ever enigmatic John K.

I agree. First of all, I know nothing about what Gena was talking about...waaay over my head! However, I know what I hear. I had a cheap Sony AVR which was rated with over 3x the power of my first Denon. The sound didn't even compare. Regardless of volume, I couldn't believe the amount of hiss that was removed with the Denon. I didn't even have to put my ear up to the speakers to notice it.

I had the same experience when I upgraded to the Denon 3805, there was no comparison between my old receiver and my new one in terms of music and movies. Mabey that was due to better processing, I'm not sure.