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The measurement and the experience
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Why don't THD and IMD measurements, or any other presently available
technical
measurements, predict which amplifiers will be preferred by cultured
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Do you understand the meaning of 'cultured'?
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listeners?
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Because they are not indicators of price or fashion..........
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A little clarification of the term 'cultured listeners' wouldn't go
amiss....??
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Experienced listeners as defined by Olson will do fine.
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I, for one, don't lose too much sleep over distortion figures - most things
of a 'sensorial' nature in this world benefit from a little distortion when
they interface with human beans, I find....
(See my smart little remark: "I'm a *consumer* who is more interested in the
sound than the signal." elsewhere.... :-)
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Must have been in the post I stopped reading when you started preaching
about "etiquette". I tend to skip the censorial in favour of the
sensory.
Andre Jute
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Andre Jute
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No idea about cultured listeners (whatever they are...have you had your ears
cultured, or are they natural), but THD and IMD and other measurements *do*
predict what the amp will sound like to experienced listeners provided that
they are over the threshold of audibility.
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In the same spirit of "pearly ears"...
Which listeners do you think are "over the threshold of audibility"? Is
this phenomenon frequency-related and consequently age-related? Can
hearing-aids help raise these listeners over the threshould of
audibility.
Or do you intend us to take it the other way round, to exclude
listeners who whisper from our test universe? What if they turn up with
megaphones?
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Seriously now, my question is not "predict what the amp will sound
like" but "predict which amp they will prefer", an entirely different
matter.
Andre Jute
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A different question indeed. If we have two amplifiers of broadly equal
power and sensitivity who's technical measurements are such that distortion
is low at all frequencies (say less than 0.1%), the frequency response into
the loudspeaker is within +-1dB 20-20k with no sharp peaks and noise is
below, say, -80dB, then I can't see how there would be a preference. If
however the measurements are worse than this, then I can't see how it would
be possible to predict: it would then be a personal choice. For example, if
we're talking about older people who's hf hearing has deteriorated, then
distortion rising even to 1-2% above 7-8k would most likely be unnoticeable.
I'm not sure what you're trying to get at with this question, as it's like
asking if you can predict if someone prefers a claret or a burgundy.
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Precisely. Winemakers use a lot of science in their process but do not
pretend to be able to explain preference arising from. Nor do they
pretend there is no such thing as taste.
Experienced listeners, while paying lip service to the
"allgoodamplifierssoundthesame" mantra, in real life express
preferences between equal-measuring amplifiers driving the same
speakers.
Since it is the mode on UKRA for a definable group to sneer and jeer at
taste, I am now asking them to explain, using any science they wish,
this substantial anomaly in their expressed worldview.
It seems to me significant that a substantial part of what they regard
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The cultured are in this regard simply regular concert goers. They are
the people who in my experience are the most likely to be also
disgruntled audiophiles, complaining that the experience in their homes
from expensive hi-fi is not the same as in the concert hall.
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That would include me, then............
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But if you need a panel, I am happy with Olson's concept of
"experienced listeners".
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That would also include me.
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This of course doesn't affect the measurements in the slightest.
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This is precisely about measurement by techies alone failing a general
market of educated consumers who feel that despite the assurances of
the lowest possible distortion expensive hi-fi still does not reproduce
the concert hall experience adequately.
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Nothing to do with the amplifiers, old son, as any engineer will tell
you. That's down to the room, the speakers and the original recording.
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We need to start far less ambitiously than fullscale psychometrics,
perhaps by merely asking a few music critics which amps they think best
reproduce the concert hall experience. At the end we want not an
academic description of effects but an analysis of reasons which can be
translated into a standard to which any arrangement of components must
answer.
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Unfortunately, amps contribute significantly less than 1% to the
problems of domestic hi-fi, so let's not waste any time blundering up
*that* blind alley. Besides, music critics are the *last* people to
ask about sound quality!
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Incidentally, there is a technical, electronic analysis of the reasons
for the dissatisfaction of experienced listeners with "harmless"
silicon and impressively noiseless big PP tube amps, which I shall
canvas in a companion thread when this one is exhausted or infested
with hairsplitters.
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No, there's just more of your windbaggery, not the same thing.
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So many amp and speaker designers use Quad ESL as their reference; that
in itself is comment on how little we have advanced since 1957 and how
far we still have to go.
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Not really, as it remains one of the least coloured of all speakers,
and can certainly find any real problems with an amplifier.
Fortunately, these are now rare - except in the 'high end', which
rather speaks for itself................
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Andre Jute
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as their own constituency agree with the contrary view, that the
measurements are not the final word, that taste is important.
Andre Jute
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Andre, There's no mystery here. Wine is sometimes chosen by taste, but all
too often by brand. I don't think the wine analogy will serve for much more.
We all possess audio equipment, whether purchased or self-built, and that
has involved a choice. How we exercise that choice is a very personal
decision. Some may choose on looks, what keeps their partner happy, what
will impress their friends, or on what it sounds like *to them* It's this
last one that I think needs further scrutiny.
We all choose equipment sighted, after all, no shop will give customers DBTs
will they. Therefore the choice, which may be made ostensibly on the matter
of sound quality, is actually made on a combination of all other factors
including looks, reputation and of course sound. If we do all subscribe to
the notion that all good amplifiers sound the same (I know, I haven't gone
through all the qualifications, you know them as well as I do) then we're
kidding ourselves that sound quality made the choice for us. Even if we
genuinely believe that good amps sound different, the overwhelming evidence
is that they don't, so, what may appear to be a matter of audio taste, in
fact is a matter of all the other non-audio factors. You are completely
right that taste is important. I contend that in the choice of good
amplifiers, that's *all* that matters, as there's no audio reason for the
choice.
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Just a small correction, Serge. While I agree that all good amplifiers
*should* sound the same, more particularly render the same window on
the concert hall, I do not agree with you that we have achieved that
position, or are even within reach of it.
That a whole bunch of similar measuring amplifiers sound the same
doesn't necessarily mean that they are any good; similarity could, and
in this case does, mean merely that they are equally bad, because the
wrong indicators (THD and the rest, which you know as well as I do)
have been measured, strived for, achieved, heavily promoted to a
gullible market, and are now strenuously defended by a rearguard of
engineers without any better ideas.
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Just to get this clear - you can't hear distortion measured by
conventional methods no matter how high?
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Andre Jute
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I think this is where we can't agree. I think amplifiers reached a level of
perfection such that they became indistinguishable one from another perhaps
some thirty years ago, maybe more. Since then, we have seen amplifiers with
a lot more power, a lot lower distortions, lower noise and wider frequency
response and all at relatively lower cost, but as far as I can tell, no
improvement in sound quality.
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How much of it is a rearguard, and how much is the mainstream, I really
don't know. What strikes me, however, is that if there had been any "better
ideas" in the past thirty or more years, I would have expected that we would
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What you describe is an homogenous commodity which, if you are correct,
would tend to a monopoly (more precisely a very few very large makers
in the field). Joan Robinson in the early 1930s already described this
economic condition, and we can see it in Coke and Pepsi today, who
distinguish themselves by expensive marketing. Why then are there so
many amp makers left? It seems to any reasonable observer that
consumers do not in fact regard current amplifiers as "perfect" and are
casting around for something better. Since it is easily proven by
orthodox electronic argument that the least competent amp is now
distortionless to many magnitudes below human hearing, that can only
mean that the parameter of perfection is mistaken.
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have heard about them. Unless I am mistaken, the old conventional
measurements are still the only ones being made, there has been nothing new.
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Frankly, I don't think in terms of a "new idea". I've had some in my
time, and made something out of them, but they were in fields a lot
less mature than analogue electronics. In amplifiers I think in terms
of a new way of looking at the problem because, as I explained to Andy
just now, the solution will have to be in the electronic
implementation. The likelihood is that reinterpretation of existing
data will provide a solution.
Andre Jute
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It's undeniably true that no hi-fi equals the live experience, although a
very few recordings come close.I think you are right that any solution will
involve an electronic implementation. You may be interested in the work
Fraunhofer IDMT and Lawo AG have done in Germany on soundfield synthesis.
They have taken a surround signal, and calculated what the soundfield needs
to be at several hundred points around the listener. At each point they have
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Ever heard Ambisonic, Serge? Four main speakers one in each corner of the
sound stage and four smaller ones, two at each side halfway between the
mains, one low and one high. With a 4 channel recording made on something
like a Calrec Soundfield mic the results are most convincing - you can
move near anywhere between the speakers and still get a very convincing
sound stage. First 'public' demonstration at an IBS meeting in the '80s at
Teddington Studios and the antics of those trying the results known as the
'Teddington Trot' ;-)
The speakers used were BBC LS 5/8 for the mains, and LS3/5a for the side
ones.
This was truly amazing for capturing a performance where a 'single' mic
could give a good balance. But very very few fit this criterion. What the
effect of mixing in spot mics might be I don't know - but suspect would
ruin it.
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Dave,
I'm very familiar with ambisonics, and all the quadraphonic systems that
preceded it. I agree, ambisonics was excellent, but as, you suggested,
didn't lend itself to spot miking and to "pop" productions. Also, at the
time, delivered by two-channel matrix means (either records or FM) resulted
in poor performance, albeit better than SQ and QS, and more practical than
CD4/UD4. It nevertheless suffered from pair-wise imaging inherent in the
basic four loudspeakers, although the side ones helped with height and to
fill in the sides.
I'm not suggesting that the Fraunhofer work represents a practical home
solution, after all how many people will want a hundred or so loudspeakers,
but it is an interesting development in trying to create a realistic
soundfield in a room.
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a small active loudspeaker, driven from a several hundred channel
router/mixer. Hardly a practical domestic solution but the demos I heard at
the AES and at IBC were most impressive for giving a live feel, not only on
music but everyday urban noises. As you know, pairwise stereo only works
well for 'speakers directly in front, works after a fashion for 'speakers
directly behind, and not at all for those on the side. The Fraunhofer
soundfield synthesis gets away from the pairwise presentation.
There's some info about this on the Fraunhofer IDMT website
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Gotta reply to this..
That'll make it 10 >'s in a row - a record as far as I'm concerned.....
.....and another sign of the decline of this group, I'm sorry to say......
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It's now 12...... I can't understand your problem with this, Keith. It's
more a sign of a civilised conversation developing rather than the
bad-tempered exchanges some other threads have degenerated into.
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