Originally Posted by Fastslappy
I got a 3008 & 5008 ..sent back the 3008.
how else would one do that test unless U had both in the house at once ? it was all by aer & I know some here don't trust ear as a measuring tool but for me they work fine , i now what i like
The problem is that it's fairly well proven by various studies that the human 'auditory memory store' is normally only able to retain information for a maximum of about 4 seconds and in exceptional circumstances for 20 seconds.* If you google "echoic sensory memory" you will find a lot of information to support that claim.
So by the time you had got the two AVRs swapped over, it's physically not possible to remember what the first one sounded like and, of course, if you can't remember what the first one sounded like, then it's impossible to compare the two in any meaningful way by using this procedure.
I agree entirely that the human ear can distinguish between the sounds of different stimuli and know which one is preferred, but - especially when the differences are going to be fairly subtle anyhow - only reliably if you can switch between them instantaneously. Any differences, therefore, that you believed you could hear would be due to complex placebo effects created by the human brain in the absence of true evidence. Unless, of course, you're saying that the 3008 and 5008 are night and day different, like, for example, a tube amplifier from the 70s and a modern digital amplifier from today - and I’d guess you're not saying that.
It's significant in this case too, for example, that the more expensive AVR was the one where you could 'clearly hear' a superior performance. To make the test valid, you would need to do it blind so that you could not know which AVR was playing. As soon as you know one is more expensive ("better"), or has an allegedly superior specification in some way than another, any objective results of the test go right out the window. I suspect you swapped the AVRs over yourself so you always knew which one was playing and that, in itself, invalidates the comparison. I should also add that the levels of both AVRs would need to be matched to +/- 1dB for the test to be valid as otherwise, the louder AVR will automatically sound "better". Again, this has been objectively proven on numerous occasions.
When people have done proper A/B tests of power amplifiers, for example, the procedure to set them up and level match them and so on is very complicated, but they can then be swapped instantly at the flick of a switch. What these tests have proved is that with two modern amplifiers working within their designed specifications, there is no audible difference between them! The testing procedure is explained in some detail here:http://www.tom-morrow-land.com/tests/ampchall/index.htm
... and anyone who can hear the difference between two amps can collect $10,000. So far, nobody has
We all have this problem in evaluating equipment of course, unless our homes are also laboratories. At the end of the day we have to go with which sound we "prefer", but truly, it is just impossible to do meaningful "A/B" comparisons simply by swapping gear around and then listening.
EDIT: On re-reading that it sounds possibly as if I am dissing your preference. I'm not. You prefer one over the other and that is all that matters - it's your dollar, your system, your ears. All I am saying is that there is, unfortunately, no way to do an objective scientifically valid A/B comparison in the way you described.
* Darwin; Turvey, Crowder (1972). "An auditory analogue of the sperling partial report procedure: Evidence for brief auditory storage".
*Glucksberg; Cowan (1970). "Memory for non-attended auditory material".