(1) Yep,. the discussion was about the 80s. I did admit the technology has gotten better and Red Book sounds far better than it used then. But in the 80s, it sucked.
(2) Subjective? How about using the same subjectivism to two experiences? That becomes objective, that is, the relative differences between the subjectivism becomes objectivism so long as the subjective criteria is constant and applied equally. Meaning, it is my opinion of both amps vs the same speaker... I'm not comparing your opinion with mine... unless, we were listening to the same thing under identical conditions, huh?
(3) That power output is a terrible way to measure an amplifier. It really should be 20Hz to 20 Khz, at a given distortion, power level and impedance AFTER one hour of 1/3 power preconditioning. That style of measuring, at 1Khz... is the old IHF style which the FTC got rid of. I would be curious to find out what the FTC power meaurements for that AVR are like for 2 and 5 channel operation. Likely far lower, and no measurement at 4 ohms.
(4) IHF like ratings are NOT honest.
Usually that means exciting the resonances... where you run into resonant behavior at certain frequencies. Since sound travels at 333 m/sec (sea level) you can do that calculations rather easily. Just calculate the length of a wavelength at any frequency and compare it to the dimensions of the room.
It is the most important at low frequencies, naturally.
The larger the room, the lower the resonance.
But, you know that.
Objective: quantifiable, measurable
Subjective: not measurable, opinion
I don't evaluate things based on opinion unless it's a mass of opinion-based data points obtained via double-blind testing.
While I agree it's not complete, it's also not wrong. The first power specification exactly conforms to
63 FR 37235 paragraph 432.2 "Required Disclosures".
The second and third specifications meet the requirements of Paragraph 432.4, "Optional Disclosures".
The above are not IHF like ratings. The old IHF "Music Power" test was derived from a 20ms tone burst. The above are continuous tone tests.
Resonances are always excited at any level. You have not clarified what is meant by "overloading the room".
Sorry to barge in here, but more than a few Pass amps have been discussed here...
There most certainly is a way for an amp to sound different, without the amp being faulty or ill designed.
Sometimes the designer knows exactly what he is doing and willingly plays with parameters to get a certain result.
What other people get out of it, by experimenting, would be hard to predict. Mr. Nelson Pass is somewhat of a legend
(and rightfully so) but he does what he does, knowingly and willingly and publishes enough articles that provide the
clues why there are perceived differences within his choices....
One of those articles is here: https://www.passdiy.com/project/amp...e-amplifiers-and-sensitive-full-range-drivers
Where he compares an SS amplifier with a current source amp, while changing full range driver parameters with passive networks.
Just exchanging amplifiers like the ones discussed in that paper is going to make audible changes as well. Only the SS amplifier is
insensitive to the changes made in speaker impedance. Unless we provide a big resister in series (also mentioned in the article) on
a big powerful amp. I wouldn't consider the amps being faulty because he's playing with these variables. It is the end user's
responsibility to "get" the concept. Mr. Pass does build big SS amplifiers too. He shares designs of his "First Watt" amplifiers that
are all designed to a certain goal.
Another reason I can come up with for an amplifier (or DAC) to sound different with regards to staging is the inter channel crosstalk.
(once there's a pretty huge amount of it)
There can be examples of that being done deliberately too. Throw a lot of woolly words at it and it will sell...
If you’ve read the thread (yeah it’s huge now) you would know that the fact that amplifiers can sound different to each other is not in question here. In fact I’ve stated more than once that a major change in technology, tubes to SS, or the current source you mention above, can result in audible change. Design goal is always a factor. The changes being suggested to the OP do no include such differences though.
The audibility of crosstalk is known. Sensitivity to crosstalk is maximum in mid-band, and falls off significantly with low frequencies (omnidirectional bass) and also with the top octave and a half or more. The threshold of audibility is around -40dB mid band. DACs have better than twice that (-80dB) without trying. To deliberately degrade that would be opening the design to a rather negative review.
I've been following this thread all along, and yes... I've seen you post that more than once, but that's not the point.
I merely posted the link to Mr. Nelson Pass's paper as it shows that large differences in frequency response can occur under certain conditions.
From the article/paper (in purple):
Conventional wisdom holds that a pure voltage source amplifier is ideal for audio applications, and generally designers of loudspeakers work to that assumption. This belief has particularly been dominant since the development of high power solid-state amplifiers that began in the 1960’s. A small minority of audiophiles thinks otherwise, and these are often people using low wattage tube amplifiers with unusual looking speakers. Well, of course entertainment is full of fringe elements.
An example plot taken from the paper:
The dotted line is driven by a voltage source and the solid line is a current source with the parallel network in the above table.
Pretty sure those large differences in frequency response will have an influence on our perception. I've played enough with tonal balance to know that much.
The paper has enough plots comparing SS to current amps to warrant perceived differences that some users here have stated. That's all. It all depends...
I merely wanted to point out that Mr. Pass plays with the variables available to him to please his own preference of high efficiency full range speakers.
I'm not even suggesting that this would be a viable solution for the OP.
There are a lot of mentions of Mr. Pass amplifiers right here in this thread. I'm not stating it would benefit the OP though. But the reasons for those perceived
differences are kristal clear to me.
I merely posted the link to Mr. Nelson Pass's paper as it shows that large differences in frequency response can occur under certain conditions.
From the article/paper (in purple):
Conventional wisdom holds that a pure voltage source amplifier is ideal for audio applications, and generally designers of loudspeakers work to that assumption. This belief has particularly been dominant since the development of high power solid-state amplifiers that began in the 1960’s. A small minority of audiophiles thinks otherwise, and these are often people using low wattage tube amplifiers with unusual looking speakers. Well, of course entertainment is full of fringe elements.
An example plot taken from the paper:
The dotted line is driven by a voltage source and the solid line is a current source with the parallel network in the above table.
Pretty sure those large differences in frequency response will have an influence on our perception. I've played enough with tonal balance to know that much.
The paper has enough plots comparing SS to current amps to warrant perceived differences that some users here have stated. That's all. It all depends...
I merely wanted to point out that Mr. Pass plays with the variables available to him to please his own preference of high efficiency full range speakers.
I'm not even suggesting that this would be a viable solution for the OP.
There are a lot of mentions of Mr. Pass amplifiers right here in this thread. I'm not stating it would benefit the OP though. But the reasons for those perceived
differences are kristal clear to me.
Again, that's not in dispute here.
Noted. So now what? When I make a statement about the audibility, or inaudibility of amplifier differences do I need to say "except for those designde by Nelson Pass"? Look, I don't look at every single amp in the world, nor do I care to. I have examined many. You can cite the "boutique" instances all you like, it's the exception, and I did, many times, state clearly that changes in technology can have audible impact.
What do you want me to do here?
OK, fine. Nothing he does affects imaging though.
Here's a plot of crosstalk from a rather lowly DAC. It's actually a USB audio interface, the Behringer UCA202. I think I paid $40, new. I did this quickly, so no smoothing or anything. Audio is output from the left, the plot is what's left over in the right channel, the crosstalk of left into right. This is not deliberate, other than it's really, really cheap. Every DAC I test is better. So, here's your "worst case".
Deliberate crosstalk is counter productive to the soundstange. 100% crosstalk is the definition of MONO. Every time you add crosstalk you reduce the soundstage toward mono. If you add out of phase or time delayed crosstalk, you're attempting interaural crosstalk cancellation, which the OP has already stated he won't try. Yes, that could significantly widen the stage, but it's also not universal or fixed, it must be adjusted for each recording. So baking it into a DAC is just plain silly. I realize there is just plain silly out there, but it doesn't make any practical sense.
Attachments
I think we crossed the world of DIY a long time ago in this thread.
I feel like I'm reading that "AudioScience" web site.. you know, the one where they measure everything and listen to nothing...
Quite defensive and an unneeded response. Many here brought up Mr. Pass amplifiers which made me point out what he does.
You didn't seem familiar with the why and how. No you don't need to know about all boutique amps. What Mr. Pass does is his business, not yours.
But... related to this thread his amplifiers get a lot of mentions and all I'm trying to do is bring you up to speed on that. (now regretting that decision)
Changing the frequency curve like the plot I showed (dotted compared to solid) DOES change perception. But it is not valid for the OP's case.
I'm not attacking you. I merely point out that the other members mentioning stuff in good faith and of good will are not grasping it out of thin air.
They are bringing up the stuff they have noticed first hand. They cannot all have had a career in Audio like you have/had. But if you try and comprehend
they mean well and some of it may be based on personal experiences, it would help to have a little more understanding of the how's and why's.
What the amplifiers like Pass is making have to do with this discussion is that there are a lot of DIY builders that have build and used them on this site.
It is a DIY audio site after all. So it may come as no surprise that successful builders want to share some of the fun (and good sounds) they experienced.
Does it help the OP? It just may help, by bringing all these stories about amplifiers into focus. It would be logical for you, @jadie to think he should
follow your advise. Because of your experience you bring a lot to the table. But how many posts have we seen of people that say: change the amp!
That will do it... All of this is adding to the confusion of the OP.
If the OP finds out why these users say such things, it will assist him in making an informed decision.
This current ping pong war of opinions isn't going to do it. No matter how long this ping pong war will last.
I'm not of a different opinion than you are on the subject of amps being able to sound different nor that they are the valid solution for the OP.
My prior posts in this thread should have made that clear. But some effort on both sides to know why changing amplifiers isn't the solution
in this case might actually help the OP.
A little respect on both sides... it does not need to be this sort of competing or conflicting opinions against each other.
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I was not even that serious about it... it's just that in this crazy world of audio almost anything gets hyped up for no reason to make a buck.
Using woolly words often being enough to make that buck. Heck, we have speaker builders that people look up to that sell "tube connectors"
for overpaid prices that are supposed to make huge differences...
Deception sells...
Oh those boys! they have fallen into the worst of sins, censorship! First they invite you to "have a good time" and not take things so seriously... and after a stroke of the pen they delete several posts to give the treahd a "nice" closure, of course with their arguments being right and "period " .
And they are not the only ones...😡
Why stop there... when we can really alter perception with a Blumlein shuffler... 😉
An old (1931) trick...
(easy to try with a PC as source)
I can't speak for anyone but myself. I measure and I listen. The major hurdle to cross is the correlation between the two. We get closer all the time.
I also see the above as a sort of declaration that measurement and listening are not recognized in DIY. I'm not sure I understand that. Every engineer who designs an audio device for the commercial market does both. Why is that not permitted here? Are we only allowed subjectivism and mythology here?
Yes. And doesn't that make it all the more important to recognize it? Even if it exists in popular audio culture?