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Discussion Starter #161
I'm sure I don't have to tell you this, but for others not picking up on it, you're comparing DACs and preamp stages in addition to amplifiers here. [Edit: unless, for the Onkyo, you're going into line-level multichannel inputs from the Oppo. Even then, you have the Onkyo's preamp circuit.] There will be those who will say that these things should be as transparent as amplifiers should be, but those who believe that amps can make a difference likely will also believe that the DAC and preamp circuits will also.

That said, I would go with the last option if you have a lot of time to compare. I haven't done a lot of this type of comparing, but it seems to me that if you're looking too hard for differences you may start to make them up in your head :coocoo:
Thanks, Brian. I am still deciding just how to set it up, what limitations to place, even how to prioritize it with other projects. Part of what you have helped me accomplish through your comments, though, is how easy it is to end up with variables one has not even thought about.:T
 

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I will soon have quiet fans installed in my Crown power amp and, along with the Oppo HA-1 acting as DAC + volume control, will be able to perform long-term listening comparisons between it and my Onkyo TX-SR705 receiver driving my MartinLogan ESL speakers. Both will receive optical input from my music server.

Which intention should I prime my mind with as I begin that exercise?
  1. "They are different amplifiers, so they must sound different, so I will find a way to hear that difference."
  2. "All amplifiers sound the same so I will not hear a difference."
  3. "If there is a difference, I will hear it, if there is none, I will not."
  4. "I do not really care. If there is enough of a difference to matter to me, my brain will find a way to let me know."
  5. "Priming my brain with an intention beforehand is a silly notion, just enjoy the music and see what happens."
  6. "All that matters is that I will end up with a preference at some point, so that must be the better amp for me."
As to part one, this will not work. Brian is correct in that you will be using a different dac in the Onkyo as well as various other computerized settings that the receiver will use in the decoding and playback of music. And as the Onkyo does not have the 7.1 ext in pass through you will always hear more than just the amp.
So this is kind of an apples to oranges test. If you know someone that can loan you another basic amplifier that would allow you to use the oppo dac direct to both then that would work better.

As to part two, I think choice 4 is more in line with what one needs to go into this with. If you hear it then you do, if you do not, then move on with the knowledge that you gave it a go. I say there are differences, often substantial differences but more often subtle differences but in my defense, I have been doing this for 35 years so I have practiced some long term listening very often. Just like putting your ESL off the carpet has changed the sound for you, once you know what to listen for, amplifiers can do the same thing.
The best thing is you will be doing this for yourself and not allowing some far off comparison from a zillion years ago, from folks that say that cannot hear a difference yet have 10's of thousands invested in amps.

I truly like your zest Wayne, you are willing to go for the gusto. :clap:
 

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...Which intention should I prime my mind with as I begin that exercise? [*]"They are different amplifiers, so they must sound different, so I will find a way to hear that difference." [*]"All amplifiers sound the same so I will not hear a difference." [*]"If there is a difference, I will hear it, if there is none, I will not." [*]"I do not really care. If there is enough of a difference to matter to me, my brain will find a way to let me know." [*]"Priming my brain with an intention beforehand is a silly notion, just enjoy the music and see what happens." [*]"All that matters is that I will end up with a preference at some point, so that must be the better amp for me."
Gotta love that! Almost works if you substitute:
  • "wine" for "amp"
  • "taste" for "sound" or "hear"
  • "experience" for "music"
But someone once told me, "Almost" only works for horseshoes and hand grenades!

Sent from my iPhone using HTShack
 

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I'm torn between #4 & #6:

"I do not really care. If there is enough of a difference to matter to me, my brain will find a way to let me know."
"All that matters is that I will end up with a preference at some point, so that must be the better amp for me."
Because in the grand sceme of things, all that matters is how we like the sound. What we already have as equiment currently...is our preference!
 

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I think 4 and 5. Your brain will let you know if it's enough to matter. Until then, enjoy the music, until your brain defaults away from one or the other. The one that's left is not the one.
 

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After some discussion with my uncle about this matter he said that even he would have some issues after listening to tons of music for durations that are full songs in length (i'm assuming fatigue?)

He mentioned the easiest way to tell and the only way he tests differences is keeping to only 3 tracks. One must be a natural string instrument like a violin or cello, the other must be a very well recorded live single mic track similiar to the Harry James recording and another is just whatever you want to use type thing, preferably something with a kick drum and/or horn he mentioned.

He went on saying that you MUST not listen longer than 1 minute of any of the 3 tracks. after a minute your brain is so complexly fooled that things get blended too easily. The way he explained it to me is with the complexity of acoustics hitting your ears that after one minute your brain will start ditching information.

1. 3 tracks only... same tracks... same media...
2. only the first minute
3. repeat that first minute with changes

This is how he told me he does it. He agree that fatigue destroys clarity.
 

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Discussion Starter #169
Gotta love that! Almost works if you substitute:
  • "wine" for "amp"
  • "taste" for "sound" or "hear"
  • "experience" for "music"
But someone once told me, "Almost" only works for horseshoes and hand grenades!

Sent from my iPhone using HTShack
LOL. I wonder if fine wine lovers have the same arguments.:huh:
 

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Discussion Starter #170
The way he explained it to me is with the complexity of acoustics hitting your ears that after one minute your brain will start ditching information.
Your uncle is wise. It is auditory adaptability that tunes out the status quo (after a minute or so) so the auditory brain can be on the lookout for something new. It is looking for contrasts. It LIKES contrast. Which is why music contains phrases and movements and key changes and... And why A/B testing works so well.

This is a tendency, though, and can be overcome SOMEWHAT with training. How much? Nobody knows.
 

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I have posted more detail in the comparison between the Denon AVR and the four amps with which it was compared in the Blind comparisons in the first post of this thread. All of the comments in the comparisons are observations from our reviewers in the blind testing, associated with the amp after the fact. The observations were about A & B, unknown to the listener at the time of the comments.

I have been over the measurements to find any correlations in the frequency response, impulse response, and distortion measures that would account for the observations that were consistent and found very little. There were slight differences in distortion and impulse response, but nothing that I would expect to account for the comments. The only significant frequency response anomoly was a slight roll off in response in the ML above 4K compared to the other amps. This was consistent with the observations.

The conclusions that I come to from all of the subjective observations in both blind and sighted conditions and the measurements confirm a few assumptions that I have been making for years. That, of course, could mean that those assumptions are justified, or that they color my assessment of the collected data. Judge that for yourself. It appears to me that because we had some consistent blind observations about some of the amp comparisons that there may be some differences that do exist that are very subtle and hard to identify in ABX testing. On the other hand, we did fail to identify the amps correctly in the ABX testing. Once again, we have a conflict between objective and subjective testing. What justifies some concern, IMNSHO, is that some of the blind observations were consistent and specific. I BELIEVE that future testing should focus on identifying observed differences and focus on extended listening with multiple trials to determine if they are, indeed, repeatable. It could be that what we observed that seemed to be consistent was simply chance. Regardless, if there are differences, they are very small, far less than many reviewers and vendors would lead us to believe. I think that this is a reasonable expectation. For those who want to extend that notion to say that there simply are no differences in amps, I have to say that you are justified in believing that. To those who argue the opposite, I would say that you, too, are justified in believing that, but you have to account for expectation bias, which, beyond any doubt, contributes to the significance attributed to any differences that are observed whether they are there or not. Once again, I take the middle road and probably don't satisfy either side. So be it, as the results here seem to justify my opinion that the correct answer is more complex than either side would like to admit.

I am working through the data in the other comparisons and will be publishing more, but the Denon was compared to 4 other amps, giving much more information and more opportunities to identify consistent observations. There won't be as much to report simply because it is more difficult to find consistency in single comparisons, but there are a few that stand out.
 

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Agree, nice write up. Thanks for all the hard work so far in doing this.

Reading into all that has been said so far I personally think that the differences between amps is small at best, not night and day. So in my opinion you can say that as long as properly matched to the load of the speaker there is not enough difference to justify the cost of the big $$ amps.
 

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Here are the frequency responses for the amps that were compared to the Denon, with the exception of the Behringer. For some reason I could not find it, but there were no noted meaningful differences at the time. I am sure we have it somewhere.

Note that the levels were matched carefully in each comparison, but there were slight differences between those pairs. I have matched the levels at 500Hz for this comparison.
 

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If $$$$$ amplifiers bring a person pleasure they are worth it.
But if the goal is to spend as little $$$ as possible to get improvement in the audio it is difficult to make the case for spending $$ on outboard amplifier/wires/accessories when speakers make so much more difference in how the audio sounds.
When recommendations are asked for to get better sound quality outboard amplifiers should be far down the list most of the time.
 

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I agree, Tony. The fact is, however, that many people DO experience differences that they find to be significant. It is real to them. What I believe these results indicate is that there are possibly differences that are audible, even if our measurements do not capture them. If we assume that SOME, even slight differences MIGHT exist, the only intellectually honest way to proceed is to try to find those that might be repeatable in objective testing. This requires identifying the most likely candidate differences, then arranging testing to facilitate identifying them without the possibility of chance influencing the results. Considering the experience of the testers here, more trials with fewer amps, more time with more breaks, and consistent passages repeatedly may be the way to go. The X option appears to be a confusing and difficult aspect of the testing. In the future I would devise a list of characteristics for each amp, then ask the listeners in blind comparisons to rate those repeatedly in randomized trials, rather than trying to rely on memory to match characteristics.

Again, the point, IMO, is to identify whether there are meaningful differences in a universe of infinite possibilities. If those identified differences are present, they should be repeatable, but we have to isolate those variables. The ABX testing obviously, based on our experience here, introduces other confounding variables.

Any time one is doing testing on something that involves human perception, isolating the variables it very difficult. This is clearly the case here.

Also, again, with all that said, we may still be talking about angels on the head of a pin in terms of the meaningfulness of any differences for most people. If you assume for a moment that the differences that we heard that MIGHT be real are, they still would not be meaningful to most people. They might to a handful of us, but even we were not impressed with the differences in terms of driving a decision to purchase, and we probably care more than all but a very small percentage of the buying public. This is really more of an academic exercise than one of usefulness to the majority of people, even those that buy very expensive amplifiers.
 

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Denon was compared to 4 other amps
I think this is the paramount interest. Do we need external amps to drive our mains when it is set for 2 channel stereo? How does the SI&D compare between the two. How perceivable is the added headroom...enough to justify the expense?

So, not so much of "which amp" as it is "how much amp?"

I would expect the differences to be increased in the HT setting.
 
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