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Review and Measurements of Benchmark AHB2 Amp

zalive

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Harbeth had a long term offer of free speakers iirc for anybody who could tell the difference between 2 properly engineered and suitable amplifiers.

What, they (Harbeth) picked two amps of their choice?
They would not allow some other suggestions for the tested amps, then evaluate whether both amps are properly engineered to allow a contest?

I say this because you can indeed find two amps based on the same topology, similar power and specs, which will indeed sound similar even in a non-blind, non-level matched test to any audiophile who is not being heavily biased. No biggie for them to make a contest out of such. Should it prove anything? It doesn't imply you can't find another two properly engineered amps of different topology sounding different enough to prove it in a DBT.

Funny, if I wanted to prove the difference can be heard in a DBT, I'd pick two amps and my own music samples. Then others are free to evaluate whether those are both properly engineered, with sufficiently flat curves and without notorious distortion etc. Then we agree on DBT listening volumes so objectivists can confirm there should be no clipping. Then mutually agree methodology of DBT. If I wanted to prove anything I would like to have my own terms, with the other side reviewing terms and methodology and agreeing whether all is correct. Not to have DBT in someone else's terms, which can be manipulated so they won't easily show any difference (bad choice of samples for the discerning purpose, for the example).
 

GrimSurfer

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Properly engineered = able to drive Harbeths. Suitable = whatever Harbeth deems. Another critical thinking sucker is born.

This bloody nonsense about two similarly spec'd amps being indistinguishable has to end. It's based on the outlandish probability of "sameness" of sound regardless of circuitry, power supply, etc. It's founded on an audio show party trick that Nelson Pass did fercheissakes. Now it's misapplied by anyone whose fingers touch a keyboard... for all to read. Over and over again.

But it's worse than that...

Manufacturers of the most outrageous dime-store shit rely on this chestnut to convince shoppers that good engineering isn't as important as a few convergent specs, omitting that their amps will sound (ahem) considerably different driving difficult loads, phase angles, at spl's of the user's choice, etc.

Buy the [insert brand name here] 7.2 500W @ 8 ohm amp, 'cause it has the same 500W as the properly engineered 2.1 amp at three times the price. When it goes into overload trying to drive 4 ohm nominal speakers @ 110 dB, sell 'em some more shit until it's time to trade up.

This is right up there with other manufacturers roundly dismissing significant differences in performance specification for no other reason than their products don't perform as well. It's just the flip side of the same industry-mediated thinking that has dragged this hobby down to a point where everyday is a new opportunity to find rock bottom in critical thinking.
 
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LTig

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I completely agree for the recording quality. It turned out that a good deal of reason why digital (CD) got a bad reputation was on poor technical and human (mastering) job in making CD-s. It's actually funny to see that it took couple of decades to learn how to do it properly and to support it with quality equipment.
You cannot generalize here. When I bought my first CD player in 1985 I also bought 3 CDs, one of them "Body and Soul" by Joe Jackson (A&M 395000-2, DDD = full digital recording). The sound quality and the dynamic is excellent, even (or especially) today. So at least a few engineers were able to do a very good job from the beginning of digital audio.
 

LTig

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[..](IME the recording quality is massively more important for SQ than the hardware we use to play it on which makes a mockery of Hi-Fi in a way anyway)
This is the best statement about sound quality I have heard in a long time. I'de rather listen to good recordings on cheap equipment than to lousy recordings on highend equipment.
 

restorer-john

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You cannot generalize here. When I bought my first CD player in 1985 I also bought 3 CDs, one of them "Body and Soul" by Joe Jackson (A&M 395000-2, DDD = full digital recording). The sound quality and the dynamic is excellent, even (or especially) today. So at least a few engineers were able to do a very good job from the beginning of digital audio.

Absolutely true. I have some very early digitals that were recorded on 50KHz Soundstream recorders, SRC'd for 16/44 and they are phenomenally good. Live to two tack etc.

If anyone has any doubt engineers didn't know what they were doing, track down some of the earliest demonstration CDs, test CDs or sample CDs.

For Jazz, look at some of Tom Jung's DMP early Sanyo pressed releases- they haven't been equalled technically IMO.

https://www.stereophile.com/interviews/604jung/index.html
 

typericey

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Which makes me wonder about the measurements of recording equipment particularly before digital. What was the bandwidth, S/N ratio, THD etc. of open reel tapes?

Case in point: listening to Can - Future Days (1972) as I type. Discovered this album/artist from a recent review by Guttenberg. Sounds fun, but you can hear the tape drop outs, and there seems to be nothing above 12kHz. :p

Anyway, obviously OT, sorry.
 

DonH56

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http://endino.com/graphs/index.html

A good R-R could push 80 dB SINAD though 70 dB'ish was probably more common. Bias bleed adding ultrasonic noise was an issue at times.
 

Sal1950

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I'm sure they sound brilliant after having been played "n" number of times in 50 years on turntables ranging from mechanical to brushless.

I try to recreate the same aura by microwaving cassettes before playing... or lovingly polishing my CDs with sand before throwing them into the tray from across the room. It adds so much... sparkle and a sense of air to my music.
ROTFLMAO
 

Sal1950

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You cannot generalize here. When I bought my first CD player in 1985 I also bought 3 CDs, one of them "Body and Soul" by Joe Jackson (A&M 395000-2, DDD = full digital recording). The sound quality and the dynamic is excellent, even (or especially) today. So at least a few engineers were able to do a very good job from the beginning of digital audio.


This is the best statement about sound quality I have heard in a long time. I'de rather listen to good recordings on cheap equipment than to lousy recordings on highend equipment.
Yea, but there's a fly in the ointment, we don't have a choice in much of the music we love. We have to take it the way it comes. :(
Very much a large part of the criticism of the sound of early CD, all of a sudden we were able to hear how bad many recordings really sounded. Spitty, sibilant vocals, cymbals that sound like bursts from an air hose, etc, etc.
Kind of the double edged sword that has been the path of HiFi over the last 70 years in general. The better our systems got, the worse much of our cherished recording were revealed to sound. Then to make it worse, over the last few decades although much has improved, the loudness wars has murdered both the remastered classics and modern recordings. :mad:
You got to be a masochist to be an audiophile. :facepalm:
 

maty

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You got to be a masochist to be an audiophile. :facepalm:

The same phenomenon happens with books, movies and other means of cultural expression. Many years ago I decided to stop buying current books, fed up with the bad written in Spanish, and the increasingly worse translations.

In music, if one focuses on jazz and classic from prestige labels it is not usual to have quality problems in the recording. As I do not like modern jazz and the current classical recordings are very bright -and worse interpreted in general- I focus on the recordings of decades ago, if possible, with analogue master origins.

I am looking, above all, to get excited, to kick the ground, to lead the orchestra ...
 

Frank Dernie

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It turned out that a good deal of reason why digital (CD) got a bad reputation was on poor technical and human (mastering) job in making CD-s. It's actually funny to see that it took couple of decades to learn how to do it properly and to support it with quality equipment.
This is also a commonly held belief which is at total variance with my experience.
Some of the best SQ CDs I own are amongst the first released in the early 80s. CDs always had a high potential which was realised from day one on many releases. In fact I would say before the days of remastering and loudness wars many CDs were better then than what is available now (except classical) since most are mastered to sound "better" by being louder :facepalm:
I had a good quality record player at the time (and still do, I have 4, all sound good to me but all different and none "accurate")
I have around 700 LPs left and about 2500 CDs. The sound quality does not IME depend on whether they are CD or LP. Superb LP recordings still sound better than average CDs but are not that common.
I have had 2 guesses why some people didn't like CD at the beginning (which always surprised me).
The first is whether their preamp clipped with a CD input. The CD player standard output was 2 volts, many line level sources before this (FM tuners, Tape decks and cassette players) had lower outputs and preamps had a typical sensitivity of 200mV for full power iirc, maybe some clipped at 2 volts???
My second, and more likely, guess is speaker response. If one had assembled a system by ear for LPs it is quite possible speakers with a rising HF response had been chosen to compensate for the treble roll off of many, maybe even most high reputation, cartidges. A source with a flat FR would then sound brighter.
Anyway I guess for many users it matters not. If somebody is convinced they have a better system that is fine but here the objective way of choosing whether you actually have got a better system rather than believing you have (whether true or not) is what it is all about. People here know how to do this. There are any number of forums (and magazines) full of (IMHO) bollox about SQ evaluations where one can comfortably continue to follow methods which have no basis in fact or IMO common sense.
Hardware wise I do still have a very old DAC, a Sony DAS-702ES, which I keep meaning to compare with a modern one (RME ADI-2 PRO) but since it is a pita to do now I don't use a separate DAC in my main system I haven't done so. One day I will take the opportunity to do a level matched listening test between them.
I did a quick compare once in somebody else's system and the old DAC sounded a bit grey and un-dynamic but it turned out his DAC had a much higher output, so this would have been the expected outcome :( one day I'll do it.
 

RayDunzl

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Frank Dernie

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What, they (Harbeth) picked two amps of their choice?
Of course not!
The amps had to be powerful enough to drive the speakers without clipping have an even frequency response and not have audible distortion level.
There was a plethora of enthusiasts who, like you, were saying much the same but nobody actually came forward to prove what they were on about.
I assume they were afraid to fail and puncture their belief.
I am sure they would have done. Both. And I think that is why none of the vociferous fans took up the challenge, fear of being the naked emperor.
 

oivavoi

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On blind and sighted listening etc. I think this debate has the tendency to become simplistic. On the one hand, it should be obvious that sighted listening is not infallible and can lead us astray. It is vitally important to have blind tests as honesty checks.

At the same time, I think it`s too simple to just discard sighted long-term listening out of hand. Humans have managed to develop quite a few things by using ear alone. Musicians, conductors, piano tuners etc - they all work (mostly) by ear, and honestly it has worked quite well. Last time I checked, the world of acoustic music was relatively well-functioning. This doesn't mean that anybody's listening is infallible, of course. But sighted listening does provide data points, at least. For those of you who are AES members, here's a fascinating paper by a couple of the engineers in Genelec: https://secure.aes.org/forum/pubs/conferences/?elib=19621

In that paper, they make the case for "slow listening" - that there may be things we don't pick up on during short listening/short testing, particularly with unfamiliar material. The reason is exactly that listening is biased: We hear what we expect to hear, and update our expectations slowly. This means that sighted listening can be very unreliable. But it also means that certain forms of blind testing can be difficult. When we don't what to listen for, or don't know what to expect, we are at a blank slate, and it's difficult to form clear sensory experiences. It may also take time for given sensory input to actually update our experience. So the more one listens to a certain input, the more likely it may be that this input may update or change our internal sensory schemas:

"If sensing primarily serves to correct experience + expectation, the time it takes to assess auditory stimuli close to what one would with unlimited time, depends almost entirely on familiarity with the features and artefacts evaluated".

I don't claim that this paper is the final word, of course, and some of their conclusions are very tentative. But I think it would be prudent to accept that sighted long-term listening may have value, and that blind testing can also give false negatives. The problem is if listeners start out with expectations which are wildly out of tune with reality: Then it can indeed take quite a long time for the sensory input to adjust the existing sensory schemas.

Another thing I find a bit curious is this: For people who really think that amplifiers etc mostly sound the same, it seems somewhat inconsistent to buy stuff like the Benchmark amp (or Hypex, for that matter). Why not get the cheapest amps possible? (that's almost what I have done, btw)
 

Wombat

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On blind and sighted listening etc. I think this debate has the tendency to become simplistic. On the one hand, it should be obvious that sighted listening is not infallible and can lead us astray. It is vitally important to have blind tests as honesty checks.

At the same time, I think it`s too simple to just discard sighted long-term listening out of hand. Humans have managed to develop quite a few things by using ear alone. Musicians, conductors, piano tuners etc - they all work (mostly) by ear, and honestly it has worked quite well. Last time I checked, the world of acoustic music was relatively well-functioning. This doesn't mean that anybody's listening is infallible, of course. But sighted listening does provide data points, at least. For those of you who are AES members, here's a fascinating paper by a couple of the engineers in Genelec: https://secure.aes.org/forum/pubs/conferences/?elib=19621

In that paper, they make the case for "slow listening" - that there may be things we don't pick up on during short listening/short testing, particularly with unfamiliar material. The reason is exactly that listening is biased: We hear what we expect to hear, and update our expectations slowly. This means that sighted listening can be very unreliable. But it also means that certain forms of blind testing can be difficult. When we don't what to listen for, or don't know what to expect, we are at a blank slate, and it's difficult to form clear sensory experiences. It may also take time for given sensory input to actually update our experience. So the more one listens to a certain input, the more likely it may be that this input may update or change our internal sensory schemas:

"If sensing primarily serves to correct experience + expectation, the time it takes to assess auditory stimuli close to what one would with unlimited time, depends almost entirely on familiarity with the features and artefacts evaluated".

I don't claim that this paper is the final word, of course, and some of their conclusions are very tentative. But I think it would be prudent to accept that sighted long-term listening may have value, and that blind testing can also give false negatives. The problem is if listeners start out with expectations which are wildly out of tune with reality: Then it can indeed take quite a long time for the sensory input to adjust the existing sensory schemas.

Another thing I find a bit curious is this: For people who really think that amplifiers etc mostly sound the same, it seems somewhat inconsistent to buy stuff like the Benchmark amp (or Hypex, for that matter). Why not get the cheapest amps possible? (that's almost what I have done, btw)


"Slow listening". Waiting for that to be independently verified. Genelec publish lots of papers. Scientific or commercial informational? :rolleyes:
 
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Sal1950

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I did a quick compare once in somebody else's system and the old DAC sounded a bit grey and un-dynamic but it turned out his DAC had a much higher output, so this would have been the expected outcome :( one day I'll do it.
Sounds like your suffering from "old audiophiles disease". The damn thing sounds good enough. ;)
 

Sal1950

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At the same time, I think it`s too simple to just discard sighted long-term listening out of hand. Humans have managed to develop quite a few things by using ear alone. Musicians, conductors, piano tuners etc - they all work (mostly) by ear, and honestly it has worked quite well. Last time I checked, the world of acoustic music was relatively well-functioning. This doesn't mean that anybody's listening is infallible, of course. But sighted listening does provide data points, at least. For those of you who are AES members, here's a fascinating paper by a couple of the engineers in Genelec:
I can buy that, to the extent of giving a listener as long as he likes to zero in on the details he believes to be hearing.
But if after all that, if he can't reliably pick them out with his eyes closed, I have to write it off as erroneous.
 

svart-hvitt

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On blind and sighted listening etc. I think this debate has the tendency to become simplistic. On the one hand, it should be obvious that sighted listening is not infallible and can lead us astray. It is vitally important to have blind tests as honesty checks.

At the same time, I think it`s too simple to just discard sighted long-term listening out of hand. Humans have managed to develop quite a few things by using ear alone. Musicians, conductors, piano tuners etc - they all work (mostly) by ear, and honestly it has worked quite well. Last time I checked, the world of acoustic music was relatively well-functioning. This doesn't mean that anybody's listening is infallible, of course. But sighted listening does provide data points, at least. For those of you who are AES members, here's a fascinating paper by a couple of the engineers in Genelec: https://secure.aes.org/forum/pubs/conferences/?elib=19621

In that paper, they make the case for "slow listening" - that there may be things we don't pick up on during short listening/short testing, particularly with unfamiliar material. The reason is exactly that listening is biased: We hear what we expect to hear, and update our expectations slowly. This means that sighted listening can be very unreliable. But it also means that certain forms of blind testing can be difficult. When we don't what to listen for, or don't know what to expect, we are at a blank slate, and it's difficult to form clear sensory experiences. It may also take time for given sensory input to actually update our experience. So the more one listens to a certain input, the more likely it may be that this input may update or change our internal sensory schemas:

"If sensing primarily serves to correct experience + expectation, the time it takes to assess auditory stimuli close to what one would with unlimited time, depends almost entirely on familiarity with the features and artefacts evaluated".

I don't claim that this paper is the final word, of course, and some of their conclusions are very tentative. But I think it would be prudent to accept that sighted long-term listening may have value, and that blind testing can also give false negatives. The problem is if listeners start out with expectations which are wildly out of tune with reality: Then it can indeed take quite a long time for the sensory input to adjust the existing sensory schemas.

Another thing I find a bit curious is this: For people who really think that amplifiers etc mostly sound the same, it seems somewhat inconsistent to buy stuff like the Benchmark amp (or Hypex, for that matter). Why not get the cheapest amps possible? (that's almost what I have done, btw)

In another thread, Klaus Heinz, founder of Hedd, talks about «dynamics» while at the same time acknowledging he can’t put to paper and into formulas what he means. So Mr. Heinz may be reflecting what may come out of «slow listening» here?

Mr. Heinz says he’s initiated a colloboration with the Uni Berlin to research this topic («dynamics»), and I guess that’s what science is often about: Having competent people observing something that later comes under scrutiny in an objective way.

To clarify my position: Observations are important. If models are uncertain, it’s particularly important to remember the observations.

This is not to say that homeopathy and astrology are all fine and ok. But we should acknowledge that few things are correct, though many things can be accurate. So standards of what is deemed «correct» are sometimes a moving target.

And you have a very good point, @oivavoi : «Transparent» amps were developed many years ago if you go by «transparency standard». Still, ASR members celebrate the AHB2 amp as if it made a difference. Don’t people see the inconsistency here?
 

Sal1950

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And you have a very good point, @oivavoi : «Transparent» amps were developed many years ago if you go by «transparency standard». Still, ASR members celebrate the AHB2 amp as if it made a difference. Don’t people see the inconsistency here?
Not really. Auto's have been fast enough for daily transportation for a long time.
But racers work to go faster every day. ;)
 

svart-hvitt

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"Slow listening". Waiting for that to be independently verified. Genelec publish lots of papers. Scientific or commercial informational? :rolleyes:

Did you read the paper? Or did you comment without reading it?
 
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