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Challenge From Harbeth - Free M40.1 For Those Who Can Identify Amplifier Differences

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Why don't you take the challenge, Steven? Your ears must be better than anyone else's on pfm, given you can hear differences in those cable lifter things.

Amplifiers should be a doddle!
 
Why don't you take the challenge, Steven? Your ears must be better than anyone else's on pfm, given you can hear differences in those cable lifter things.

Amplifiers should be a doddle!

Steven Toy... take part in a blind, level-matched test?

The universe would implode for sure...
 
Also with a valve amplifier, the distortion is generally considerably higher, especially at the frequency extremes such that again, this could be audible when compared with a SS amplifier.

Perhaps the Linn Klimax, Naim 250 and a Quad 405.2 or 606? (or a Behringer A500?)

So in fact what you have been saying repeatedly for a long time now is not that all amps sound the same, but that 3 or 4 solid state amps you are acquainted with sound quite similar.
 
I don't get the challenge...

He is saying we have to level match AND account for variations in frequency response!!!!!

How are we meant to account for frequency response?? By definition if there are frequency response variations then that is saying that the amps do indeed souind different. OK, so you could measure each amp and then put an equaliser in the system to compensate - but what is the point of that?
 
So in fact what you have been saying repeatedly for a long time now is not that all amps sound the same, but that 3 or 4 solid state amps you are acquainted with sound quite similar.
Hmm, I thought he was saying "here are amplifiers that have no (deliberate or otherwise) flaws like distortion at certain frequencies, so distinguishing between these would prove beyond doubt that all amplifiers do not sound the same".
 
so lots of highly vocal pfmers have a chance to prove a point at no cost to themselves with the chance to 'win' thousands of pounds worth of brand new speaker in a chosen veneer and no one wants to do it unless they can nobble it in some ways.....you couldn't make it up.....just bloody do it you have nothing to lose.....
 
eek I agree with both the last posts.

Must have a serious think about this...

I really would love someone from here to do this. I frankly can't be arsed and don't have a discerning ear (excuse the phrase!) but would love to see what the results were. Maybe martin, you could get a 'foo lover' and a 'serge type' together to do it with you. Although I do think 60/100 could easily fail (/succeed I guess) on natural variation.
 
Martin,

I'm neither a lover of foo nor a Serge type, but if you need someone with golden ears, impeccable taste and an inhuman command of original Star Trek trivia you know who to ask.

(The Trek bit is irrelevant. I just want to narrow the list of potential 40.1 winners.)

Joe
 
Martin,

I'm neither a lover of foo nor a Serge type, but if you need someone with golden ears, impeccable taste and an inhuman command of original Star Trek trivia you know who to ask.

(The Trek bit is irrelevant. I just want to narrow the list of potential 40.1 winners.)

Joe

Thanks Joe. Could you PM me their username?
 
but if you need someone with golden ears, impeccable taste and an inhuman command of original Star Trek trivia you know who to ask

NO DOUBLEBLINDTEST I

Horta.jpg
 
Sorry Joe, not sure what happened there.

I do have lobeless ears (true!); but not sure I give a sufficiently-large damn to attempt the challenge.
 
The Harbeth forum is back and running now. Folks can now access the original message by clicking the link on the front page of this thread, 4 pages long altogether.

AS has further clarified on his plan and intention in carrying out the listening test in his latest post. If I am interpreting it correctly, he is suggesting an instantaneous changeover with the switch-over box between two amplifiers, and the listening process is just a few seconds before and after the changeover(which takes place in a split second). Perhaps he meant listening to a track for two to three seconds with amplifier A, do the changeover and listen to the same track for another few seconds with amplifier B. Apparently he is not in favour of folks listening to the entire track. If that is the case, obviously no one would win a pair of M40.1.

Message from AS as below. Salient points in bold.

__________________________________________________________________________________________________________________________________________________________________________
Just to be clear about this amp comparison subject as I've heard that some other forums seem to have misunderstood our intentions ....

1) We definitely, 100% do believe that people (including me) can, do and will hear differences between amplifiers randomly put in front of us, hooked up, switched on and turned up!

2) We have observed that for psychoacoustic reasons that we do not understand or pretend to understand, when those very same amps are level matched (with test equipment) and then connected to a good quality relay change-over driving one pair of speaker, that when the change-over is operated entirely at random, those big initial differences heard in 1) diminish to little or nothing. So much so that it's actually not possible (in many instances) to hear any discontinuity or change in the music at all, except the minute gap as the relays flick over - perhaps one thousandth of a second. Even that may not be audible. Surprising, yes it is to me as well. This is, I agree, counter-intuitive.

3) We send all those that make amplifiers our good wishes. If the test revealed - and it would be worth at least one pair of M40.1s - that one amplifier was of such easily demonstrable sonic superiority to all other contenders (I'd buy it immediately) it would truly be a match for our RADIAL cone technology. The entire hi-fi industry would have taken a genuine leap forward and a golden nugget revealed which we'd all do very well to buy. I look forward to that revelation. That designer, that company deserve to be hugely successful.

The way things currently stand, every hifi amplifier designer is claiming that his amp 'sounds the best'. That means that, if there really is a golden amplifier amongst the pack, we are missing it due to the marketing clamour surrounding all the other amplifiers. They cannot all 'be the best' can they.

That's our sole point. We wish we understood the human ear better. Exactly why this switch over test 'levels' what are initially significant performance differences is a mystery. Pass this on.

P.S. Link to switch-over box design is here.
P.P.S. As a point of clarification, I never listen to more than a few seconds of music before switching over: listening to an entire track is unthinkable. See the next post ... #44

Tidying up the server just now, I found a PDF containing a video from a few years ago. I'd forgotten that I made this at the previous listening room and I could film this in much better quality now. Apologies for the picture/sound quality.

The way I work is all about instantaneous change-over. I do not trust my own audio memory. This video shows the foot switch in operation (the actual switch-over box is under the speaker stand). It allows me to compare two speakers instantaneously against each other - an M40 v. an M40.1 - then comparing one with a SHL5, and finally one with the M30. No need to move from the hot spot. No need to listen to the same full track (boring, soporific, teaches you nothing - listening at this time is not for pleasure). Just click-click and change over. You may just about be able to hear the difference in sound picked-up by the camera's inbuilt microphone.

So, when comparing amplifiers you use the switch box in reverse: two stereo amplifiers drive one pair of speakers and can can be switched-over to just as fast as you can hear the speakers change over. Completely foolproof. Totally eliminates memory, and most important, emotion, fatigue and attention drift.


Alan A. Shaw
Designer, owner
Harbeth Audio UK

___________________________________________________________________________________________________________________________________________________________________________

Personally I cannot fathom this. The instantenous changeover method appears to be regarded as the one and only valid test in authoritatively claiming that differences in amplifiers do not exist. The practice of listening to an entire track, or perhaps a few minutes of a track is not considered as a valid or proper system.

In adopting the instantanenous changeover test, it was mentioned that this would eliminate memory and most importantly emotion, fatigue and attention drift. Again, I am at a loss here. I suppose AS wanted to eliminate the function of short-term memory, a necessary tool in the way the human brain analyses sound wave when it travels to the ear before being transformed into nerve pulses and processed by the brain. With just few seconds of listening to a track, there is insufficient time for the brain to process the potential differences in sound(with the changeover) and store them in memory.

It would be a futile exercise if the test methods can't be agreed upon. From the looks of it, a landslide win for Harbeth if their test method is adopted. Folks who can perceive differences in amplifiers will then be considered as imagining things, listening to differences that do not exist in their heads.

I would like to have a shot at an M30 in tiger ebony, though it appears that Harbeth already have their plan well thought out.

On a separate matter, similarly I was little confused on the earlier statement Harbeth made about (attenuating?) differences in frequency response in amplifiers when they mention about doing the test in a controlled experiment with all variables accounted for. Not too sure if they are planning to disqualify any amp with an irregular or uneven frequency response, or they would insert an equalizer of some sort in the circuit to account for the variations. Again, that would further defeat the purpose of the proposed test.
 
If your amp doesn't have a flat frequency response, - it's broken.

Two amplifiers could be flat within their respective passbands, but have different bandwidth. They'd both be flat, but still have differing frequency responses.



I don't think it should be hard to tell a Quad 303 from a Spectral DMA-100S, or between a Hafler DH-200 and a Pass Labs X150.5, or between an Advent Receiver and an Ongaku, but coming up with a transparent switching apparatus that matches levels might be a bit of a challenge. I suggest that the switching apparatus is likely to be so bad as to swamp the differences between power sources.
 
so lots of highly vocal pfmers have a chance to prove a point at no cost to themselves with the chance to 'win' thousands of pounds worth of brand new speaker in a chosen veneer and no one wants to do it unless they can nobble it in some ways.....you couldn't make it up.....just bloody do it you have nothing to lose.....


To go and set up a experiment costs time and money, all to win a pair of speakers we don't need. Also I do believe that if you mess with frequency response and set two amps, one high power the other low, at low enough listening levels they likely will sound the same anyway.

Also I don't believe the quick switching method suggested is a good methodology. It wont determine subtle but important differences that become apparent over long term usage, its only useful if frequency response differences are gross.

To suggest than amps with variety of frequency responses other than flat are broken, is not to understand their purpose.

I would suggest that most people have rooms too small, speakers with no real bass, play mostly compressed recordings and don't listen at loud enough levels for "flat" amplifiers to sound good.
 
I agree about clipping, but not frequency response variations.

If your amp doesn't have a flat frequency response, - it's broken.

JC

True, also the power bandwith needs to be addressed. A power amp with a gutless power supply will be able to produce 20 Hz at low levels but not at the "rated" output. You would have to test for this as well as level matching. A 1000 watt amplifier would need to be tested at, 5 watts to sound the the same as a puny one for example. This is how I interperate the "within the power range" stipulation.
The rationale behind this test as I understand it to be is to show(for once and for all) that amplifiers of exactly the same (very basic) specification as outlined in the rules will sound the same. Or to put it another way, there are no magic, unknown, exotic component, insert your own bete noir, reasons why an amplifier will sound better or worse than any other. I have an open mind still about this, surely there will be something out there that will gain the prize but you can be sure AS has tried this many times in developing his ranges of loudspeakers oner the years and he is sure of his ground.
He is clearly proud of his designs and as an easy load presented to any amplifier he is asserting that any amplifier will sound the same into them and he is putting up a challenge which has got us talking rather sensibly since the golden eared micro-tweekers are mostly keeping their heads down.
 
It is the switching apparatus that will be the ultimate caveat, so it seems, as well as the switching process itself. When you make the switch you are not comparing the same sounds; what you hear after the switcheover is different from what you heard before anyway as music is a phenomenological series of events in the cosmic time domain. The only true test is comparing exactly the same material, the same portion of a given track therefore needs to be heard twice. Unfortunately this relies on memory.

Whilst memory may be poor for retaining given characteristics of individual sounds, it may be astonishingly good at noting the relationship between different sounds occuring both sequentially and simultaneously.
 
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