Are you claiming that two amplifiers with very low distortion, 'below audibility', always sound the same? How about slew rate? IM? What is this 'magic' % distortion you claim inaudible?
So you learnt to listen to a difference in 2 files. That does not make your listening capabilities better than the estimated center of a threshold bell curve. And it definitely does not make your subjective views on sound quality better than anybody elses.
Would you agree that two otherwise perfect amps with very low distortion should sound the same?
Assuming they are not clipping or slew rate limited?
Why do amplifiers sound different?
Or to be pedantic, why do amplifiers make speakers sound different?
It's easy to read Mr Self's book and go along with the 'Blameless' concept, but a lot of people find differences between amps.
Personally I think the interactions between amp and speaker are the big complication.
Personally I have an odd collection of amps and speakers, I know that various permutations sound different, I'm not sure which is 'best', generally I'm happy with an Arcam amp and some Wharfedale speakers, it seems good enough to make me think about the music and the musicians, but I'm open minded about finding 'better'. It's questionable whether I'd know 'better' if I met it.
There was a well-publicized test done 20 or 30 yrs ago where Carver challenged reviewers in the US to tell the difference between a highly rated amplifier and one of his that had been tweaked to have the same frequency response characteristics in IIRC an ABX test. The two Stereophile reviewers could not tell the difference and Bob Carver won the challenge.
YMMV
I don't think all amplifiers sound the same. But I do think distortion below a certain level is overrated and often at the expense of other parameters. If the designer is aware of these things, or made aware of them during the design phase, and takes the necessary steps to address possible shortcomings, an all-round better amplifier will be the result IMV.
Here is the Bob Carver story taken from his website: -
"The Carver / Stereophile Magazine Challenge
(Our thanks to Wikipedia https://en.wikipedia.org/wiki/Bob_Carver excerpted from Wikipedia in order to maintain some level of objectivity)Carver caused a stir in the industry in the mid-1980s when he challenged two high-end audio magazines to give him any audio amplifier at any price, and he’d duplicate its sound in one of his lower cost (and usually much more powerful) designs.
In 1985, Stereophile magazine challenged Bob to copy a Conrad-Johnson Premier Five (the make and model was not named then, but revealed later) amplifier at their offices in New Mexico within 48 hours. The Conrad Johnson amplifiers were one of the most highly regarded amplifiers of the day, costing in excess of $6,000 a pair.
Of note that … the challenging amplifier could only be treated as a “black box” and could not even have its lid removed. Nevertheless, Carver, using null difference testing, (null difference testing consists of driving two different amplifiers with identical signal sources and exact levels, but out of phase by exactly 180 degrees.
If the amplifiers were 100% identical, no sound would be heard. If sound was heard, the audio amps had different properties). Bob Carver used "distortion pots" to introduce amplifier characteristics, fine-tuned to null-out any sound differences.
His "motel-room" modified amplifier sound was so similar, Stereophile Magazine editors could not tell the difference between his amplifier and one costing more than $6,000. This amplifier was marketed as the M1.0t for about $400.00. Bob Carver may have single-handedly debunked any number of theories about sound quality by using physics, blind and double-blind testing and unbiased measurements (such as "gold-plated speaker wires sound better than copper wires", etc.).
graph.
Carver successfully copied the sound of the target amplifier and won the challenge. The Stereophile employees failed to pass a single blind test with their own equipment in their own listening room. He marketed “t” versions of his amplifiers incorporating the sound of the Mark Levinson and Conrad Johnson designs which caused him some criticism by those who failed to understand the true nature of the challenge — that it was possible to duplicate an audio amplifier's sound in two completely dissimilar designs.
In light of this criticism, Carver went on to design the Silver Seven, the most expensive and esoteric conventional amplifier up to that time."
Note, Carver used a 'null test' technique to modify the response of his amplifier to match the Conrad-Johnson amp, so he was able to tweak his amp in a motel room with a few resistors and capacitors, so the story goes.
I did a quick listening but left it at that. IMO it is pointless to use amplified live music to demonstrate small differences in distortion and noise.
Hmmm ..., I have read Mark's two PMs. I have not received any ABX reports with test results. I have received impressions and the statement that "Bottom line is foobar ABX doesn't prove anything" and explanations that foobar ABX is a wrong tool. Such explanations are pointless, to me. OK, we cannot find a common language and at this point I am going to stop. I only wonder why impression makers have a feeling that they must contribute in technically oriented threads.
The result would be and is same with classical music as well. There is no valid positive ABX report, but sometimes there are impressions.
Lets keep on track.
Are we going to get a group together per post https://www.diyaudio.com/community/...overall-amplifier-quality.407222/post-7563284
Looking for 5 volunteers
🙂
Are we going to get a group together per post https://www.diyaudio.com/community/...overall-amplifier-quality.407222/post-7563284
Looking for 5 volunteers
🙂
Audibility of distortion on a pure sine is much much higher than with music. If you want to play with distortion audibility on music samples, play with this SW:
https://distortaudio.org/
https://distortaudio.org/
Okay, here is why I said that. There a number of virtual patch bay apps for windows. Here is one example: https://lawo.com/products/r3lay-vpb/
All one has to do is route FoobarABX output into such a patch bay using ASIO or WASAPI Exclusive Drivers. Patch one output to your sound card. Patch a duplicate output into the input of a DAW. When the test file is played, record the first few seconds into the DAW. Expand out the time scale so you can see individual samples. The samples will be in the same place on the audio waveform as they are in the original file. Now you know which file is playing. You can choose any score you want in FoobarABX and know every time what the correct answer is.
Hence, foobar ABX doesn't prove anything.
Regarding PMAs files:
dacamp_test1.flac is bright and somewhat distorted sounding at HF. Could be the original recording sounds a lot like that to begin with.
dacamp_test2.flac is dark and muddy, with muffled HF.
Neither one sounds good. My guess was that the bright one had more distortion. Apparently not. Apparently the mud in the second file was worse. Either way, they sound different.
Since PMA in his own words described how he passed ABX using only a few trials or he would lose concentration, I also call out ABX as BS on that basis (particularly foobarABX). There are better protocols and there needs to be better testing software.
If maybe Adason or if there is someone else who can hear a difference between the two files, I would like to know their impressions. PM would be fine so the thread is not further disturbed.
Last edited:
Strange mindset. Most people use FoobarABX as a tool for making AB comparisons or for honestly self-assessing their audio setup and listening capabilities. You seem to think it is about who gets the highest score. Instead of all your ranting you could have just used FoobarABX without cheating and posted the score. If the difference is as audible as you claim the score would have shown that.
More people like (have a preference toward)
better.
Who cares (other than the people selling stuff) what people's preferences indicate?
For the purposes of this thread, we're dealing with a subjective rating / scoring system wrapped around objective testing.
The discussion about audibility of differences/discernment may be relevant. The discussion of preference is not (IMO).
If it were universally agreed what levels of whatever metric were discernable to a certain percentage of the population, this would not be the never-ending discussion.
If the metrics were simply reported as data instead of scored / weighted, this would not be the never-ending discussion.
Who cares (other than the people selling stuff) what people's preferences indicate?
For the purposes of this thread, we're dealing with a subjective rating / scoring system wrapped around objective testing.
The discussion about audibility of differences/discernment may be relevant. The discussion of preference is not (IMO).
If it were universally agreed what levels of whatever metric were discernable to a certain percentage of the population, this would not be the never-ending discussion.
If the metrics were simply reported as data instead of scored / weighted, this would not be the never-ending discussion.