Originally Posted by _Michaelangelo_
Yes -- use an SPL meter to make sure the volumes are the same, and then A/B the AVR and AMP.
_WHY_ there is even a difference in the first place though?
Let's turn to basic Math to tell us:
* A 5.1 $1000 AVR, let's be extremely generous and say, has roughly 75% of circuity for audio. That's $125 of parts/channel dedicated to audio.
* Now compare and contrast to a two channel $1000 amp which has 100% of circuity for audio. That's $500 of parts/channel. The fact that the circuit designer doesn't have to worry about "video noise leakage" means the (audio) quality _should_ be better. This isn't rocket science, just basic engineering.
So with the higher budget to play with, who do you think is going to chose the higher quality components? The AVR jack-of-all-trades that is going with the cheapest components to get the cost as low as possible, or the AMP master-of-one who doesn't have to pander to the race-to-the-bottom-of-the-barrrel extremely price conscientious consumer?
Obviously DSP room correction changes the equation, but dollars for dollars, a 2 ch amp should sound better then an AVR. Obviously, there are always exceptions.
Something else to keep in mind is that Music usually doesn't get down to 20 Hz the way Movies do. Sometimes you'll see amps sacrifice "extension", that is, fall off sharply at 40 Hz but what they give up they gain in quality -- they are much "flatter" across the board.
Audio quality is a constant battle between:
* crossover balance
* DSP correction for sound nodes and sound nulls,
This is why the one person can love one amp and another person can hate it.
This week I got to hear the Cambridge Audio CXA80 and the Yamaha A-S801. Immediately I noticed A-S801 was "brighter" -- the salesman was surprised I picked up on it so quickly -- but it was obvious to me. Some people prefer the "brighter" sounds, others want a more "neutral" or "laid back" feel.
It all depends on what you prefer.
Probably, but as I've said in other threads:
The _only_ way to KNOW is to listen in YOUR room -- because otherwise you're just listening to someone else's hyperbole.
I find slightly brighter sound likely the result of excess odd harmonics THD. My Acurus 200WX3 is a little bright and thinner, it turn out it was under biased on top of the circuit topology. It help when I adjust the bias to spec. But there is no simple fix to lower the odd harmonics.
I studied a lot of power amp schematics( I have a library of schematics from like Krell, Bryston, Cary, Pass Lab, Threshold, Acuphase, Mark Levinston, Adcom, Mcintach etc.), I never ones saw a power amp that the designer put any circuit to make it brighter or warmer.
I don't know anything about Yamaha, I can't comment on their quality. I do know Doug Self that wrote one of the two most famous book for power amp design and theory. He designed some of the Cambridge Sound amplifiers. He even have a patent on how to stay away from the crossover distortion area in the power amp. I would imagine the ones he designed is of good quality.
Listen and compare is the only way to tell. THD and output power spec do not mean a thing just listen to it. As I kept saying, if you don't have the ears, buy the cheaper one that sounds the same. Consider yourself lucky you don't have to spend the money!!! If you can hear the difference, then you are the unlucky ones that has to dole out money.
As for using the SPL meter to measure the volume, I don't see how you can read the meter as the meter keep jumping around with the sound. The music is never constant level, and is inaccurate to rely on the peak detector reading. You want to have more accurate matching, design a test fixture that can switch from one to the other amp by a flick of a switch or even remote switching. So you can sit at the sweet spot and switch instantly between the two amps. I designed and build one of this switch already and use it when I finish building my own design.