Advice: Amp building
 

In article ,
Wally wrote:
If you believe that the musicians, singers etc have a clue what they
are doing, and publish a product containing the emotion they want to
impart, then a system that delivers that without overlaying a load of
other stuff is a very useful aspiration.

Who cares about what the musicians want to impart?

The whole process of making a music recording involves 'the musicians' in
the form of a producer or whatever. You don't just throw a mic in the room
and say 'that's it'.

The best recordings capture the performance and the acoustic of the venue
very closely indeed - and just simply won't be 'improved' by anything you
do at home. Changed, however, they certainly can be.

--
*Is it true that cannibals don't eat clowns because they taste funny?

Dave Plowman London SW
To e-mail, change noise into sound.

Advice: Amp building
 

Dave Plowman (News) wrote:

Why should he?
So that it has some meaning?
What makes you think it hasn't?

Words generally do. When used correctly.

The meanings of words can vary with context. For example, the meaning of
"better" depends very much on the context within which it's used. Keith has
clearly stated, many times, what his context is. You seem to think that
"better" in here can only mean 'more accurate'. He isn't comparing accuracy,
but the emotional responses that particular systems illicit. Basing your
protestations on some other context and declaring that he's wrong doesn't
make it true.


--
Wally
www.wally.myby.co.uk
Things are always clearer in the cold, post-upload light.

Advice: Amp building
 

Dave Plowman (News) wrote:
In article ,
Rob wrote:
I think that works pretty well. Over on the digital tv ng (where DP is
sweetness and light!) you wouldn't believe the evangelism that goes with
the CRT/LCD/plasma etc debate (well, you would), all backed up with some
stonking technobabble. Understanding that 'preference counts' causes all
sorts of difficulties.

Nothing like the technobabble you get here.


Still stonking on occasion :-)

If someone wants a TV they can hang on the wall, they have no option but
to get a plasma or LCD type. And if you want a large screen CRT is ruled
out.

However, for the very best quality picture up to about 32", CRT wins every
time.

I prefer my Sony LCD in this regard to the CRTs I have experience of
(Panasonic and Philips).

In the larger screen sizes of floor standing installations there are pros
and cons between LCD, Plasma and DLP. I chose DLP because space isn't a
problem and it is better value for money.

Before I bought the LCD I looked at a couple of DLPs - the picture was
'nice' but rather washed out and lacking contrast. I'm not sure why -
they seem to get good reviews, and as you say, they're considerably cheaper.

Rob

Advice: Amp building
 

Dave Plowman (News) wrote:

Who cares about what the musicians want to impart?

The whole process of making a music recording involves 'the
musicians' in the form of a producer or whatever. You don't just
throw a mic in the room and say 'that's it'.

I realise that. My point is that the emotions we feel when listening to a
particular recording on a particular system are subject to more than just
the sound - we each have a lifetime-thus-far of empirical experiences which
are also factored in. Whatever it is that we 'pick up' as listeners is more
than what the musicians might be seeking to impart...

The musician has no way of knowing whether the listener's emotional
experience will be what they intend.

The listener has no way of know whether his emotional experience is that
intended by the musician.


The best recordings capture the performance and the acoustic of the
venue very closely indeed ...

Which is all fine and jolly, provided we like the acoustic of the venue.


... - and just simply won't be 'improved' by
anything you do at home. Changed, however, they certainly can be.

Indeed, and if it is being changed, then I think the idea is to change it to
something that is preferred.


--
Wally
www.wally.myby.co.uk
You're unique - just like everybody else.

Advice: Amp building
 

In article , Rob
wrote:
Jim Lesurf wrote:


What is 'the' scientific method - intrigued!

Pretty much, it what I summarised. The key point is that you set out
to collect data in a way that allows you to assess the results for
relevance, reliability, etc. In particular, you test in ways where the
outcome can 'falsify' the ideas you before you started.

That's fine, but I'm concerned about where your original
ideas/hypotheses come/came from.

That would depend on the case/circumstances.

In general, the process of the scientific method starts from some
observations about the real world. It is then open to anyone to propose a
'hypothesis' which tries to explain these observations in terms of a
proposed underlaying physical process. This may be based upon spotting
apparent similarities, or parallels, or links with other observations or
theories which have been successful in explaining observations in other
areas, or in the past.

However that is just the start. It is then vital that the hypothesis be
*testable*. i.e. that we can then carry out some new observations,
generally as part of an experimental process, to gather new results which
might either 'support' or 'contradict' the hypothesis.

The above point is important in the scientific method. We need to be able
to carry out tests *whose outcome might show our hypothesis was
ill-founded*. In the jargon of experimental method the hypothesis must be
'falsifiable'. i.e. we have some experiment or new observations we can
obtain which would have the ability to indicate that the idea (hypothesis)
wasn't a good one.

Thus experiments are designed with the specific aim of having the ability
to show the idea(s) they are testing may be wrong as descriptions of
reality. If we can't do any such experiments, or make any such
observations, then the idea would be regarded as 'not a scientific
description of reality'.

If the results of the experiment support the hypothesis, then we would
regard the hypothesis as being of some use. But we would then try again to
see if we could 'catch it out' with some fresh observations or experiments.
We'd also search for any possible contradictions between the idea and other
ideas (theories) that have stood up to repeated tests in the past.

The results of this process are a set of interlinked ideas which have
'survived' a number of 'challenges' in the form of experiments that tried
to find flaws in their description of reality. But these ideas are always
'provisional' in that we may eventually find flaws, and then have to come
up with a new idea. We leep on trying to find flaws, and then use these as
the 'seed' of some new ideas.

So, for example, Newton's Laws of motion 'survived' many such experimental
tests over many years, but were eventually superceeded by Einstein's
theories. The reason being that we found circumstances where Newton's ideas
did not accurately describe how things behaved, but Einstein's ideas did.
We still use Newton's ideas as an 'approximation', though, which gives
useful results in many cases without the complications of Einstein's.

But given what I have described, it should be no surprise that there are
people proposing new ideas which could superceed Relativity as the basis of
gravitation, etc. Here the main bone of contention are issues like galactic
rotation and having to use the idea of 'dark matter' to make the
observations fit Einstein's theories. At present we have no idea if
Einstein's ideas will 'survive' this - but even if they do, they may be
replaced at some point - when the evidence shows this is appropriate.


The purpose of collecting a fair amount of data/results is to enable
you to see if the results aren't likely to be due to 'chance'. It also
is to allow you to 'randomise' other factors which may be altering the
individual results as a result of an uncontrolled variable.


Are you saying that any one circumstance (a fast lap time, say) can be
explained by a finite number of variables? Is that the theory behind
your method? I don't think you're saying quite that (yours might be a
reasonable or approximate truth), but in this context I'm unclear
how/why/if you rank variables. To understand 'the' method I'd have to
know how, as a point of method, these things are dealt with.

This is a different, but related issue. This the topic of experimental
design and the methods/protocols used to actually collect observations.
This is quite a complex topic, and the details vary depending on the area
of study to some extent. However I will try to give an outline.

The basic problem is that when you make an observation, that - in itself -
does not generally tell you *why* the outcome was as observed.

There will tend to be 'uncontrolled' variables which may affect the
results. Some of these may be 'known' in the sense that you are aware of
them, and would expect them to be likely to have some effect. Others may be
'unknown' in that you either have no awareness that the variable exists, or
it has not occurred to anyone that it could affect the results you obtain.

I would not describe these as a 'finite number' of variabled. Better to say
an 'undefined' number or 'unknown' number.

We can try to deal with these in various ways, and I can give some
examples.

In some cases the variable may be controllable. For example for some
experiments we may expect the results to be affected by temperature, and
can then run the experiment and collect observations while keeping the
system being experimented on in a 'controlled environment' where we
maintain a steady, known, temperature. In this way some 'uncontrolled'
variables can be controlled, and we tackle the problem in that way.

In some cases we can't control the variable. So we may know that
temperature has some effect, but the nature of what we are studying makes
it impossible to actually control the temperature. We can then proceed in
various ways.

One way would be to only run the experiments when the temperature just
happens to be a pre-chosen value. Thus we aren't controlling the variable,
but selecting when it is at a given level. This means that we we repeatedly
take observations, any change should not be due to temperature, but may be
for some other reason, and so we have excluded temperature effects.

The above may be frustrating as we waste time waiting. So a common
alternative is to keep repeating the experiment and taking observations,
noting the temperature each time we do so. When doing this, we keep
repeating the same conditions of interest. For example, lets assume that we
are interested in the effects of, say, magnetic field, on something. We
make repeated measurements, but use the same set of field levels on many
occasions. This means we now have many observations for *each* chosen field
level, but for various temperatures.

We'd group the results into sets with the same field level, and in each
group see how the results show any temperature effect. By selection we are
controlling the field level to discover the temperature effects.

We'd then reverse this and group the results into sets with the same
temperature, and in each group see how the results show field effects.

This is seperating out different variables.

An alternative, and common, approach is 'randomisation'. Here we keep
running the experiment, applying different fields, but using the same set
of levels many many times. We go on doing this over a long enough period
that the temperature will have varied around, going up and down many times.
We then regard the temperature effects as a source of 'noise'. This
randomising works provided we can ensure the temperature isn't correlated
with the thing (field in this example) whose effects we are trying to
determine.

The snag is that we have to make many measurements, and the do an
appropriate statistical analysis to determine if the results show anything
at all with any level of reliability. We also have to accept that there is
always a non-zero chance that an outcome was produced by the 'noise' and
has fooled us. The purpose of many repeated 'randomised' tries is to reduce
the chance of such a 'noise-created' outcome to being so small that we
don't feel we have to worry about it.

The purpose of trying to exclude some factors (e.g. not telling the
'driver' what arrangement/chance is being tried) is to see if their
opinions on what is going on mean anything.

That's OK as it goes, and is a reference to DBT I suppose. The problem
in an audio context (and motoring) is that you cannot, I think, isolate
or reduce testing to fixed/certain variables.

DBT is one form of protocol, but I wasn't necessarily meaning DBT.

The experimental protocol, however, has to employ a mix of 'controlling
variables' and 'randomisation'. So, for example, ensuring a 'blind' test
means we can see if the judgements of the people who say they can tell A
from B are actually reliable. But to do this, the test has to be done
enough times for us to establish what level of 'confidence' we can put on
the result.

The randomisation for listening tests also helps us with uncontrolled
variables. e.g. lets imagine that the speakers used warm up with us, or
during the day, and this alters their behaviour to an audible extent.

if we simply allowed someone to listend to item 'A' via the speakers, and
then item 'B'. they might say, "A sounds different to B' and give a
description that others taking the same test would agree with
independently. However unless we take care, the conclusion may be that 'A
sounds different to B in this way...'

But the reality might be that 'A was always tried before B, and the
speakers were temporarily altered by trying A'.

Hence such an experimental protocol might simply lead to a mistaken belief.

To avoid this, we would have to repeat the comparison many times,
sometimes using A then B, sometimes B then A. This would 'randomise' the
effects of the speaker warming up upon the end results when they were
analysed.

I have tried to give some simplified examples, so I have left out a lot,
but you can see that the above is already quite a long description. In
practice, the design of experimental protocols and methods can be very
demanding.



The idea is also to see if you can 'catch out' the ideas people have
and find they have flaws, or are making an error. Not simply to find
'support for a belief'.

The actual experimental protocol would vary according to the aims of
the specific area being investigated. So for a specific case we'd have
to lay out a more detailed set of methods.


There is a simple difference in your view of 'the' scientific method and
mine. I believe that some data is not not 'seen', and some is not
measurable in a consistent fashion.

If it is not seen then it is not 'data'. However if you mean that there are
variables of which we may be unaware, then I agree. This is where the
correct experimental methods come to our aid but we cannot give an
absolute guarantee we have 'eliminated' any effects. All we can do is
reduce the chance that they have caused a misleading result, and perhaps do
more experiments in the future. Thus scientific understanding is always
provisional and a matter of finite levels of confidence rather than
absolute certainty.

Does the above make sense as an explanation? Afraid it is longer than I
might like, but as someone else once said, "I could have made it shorter if
I'd had more time". :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Advice: Amp building
 

Rob wrote:


Cheers Nick - you're quite right in the sense of Jim's post. My point
was that there are other methods, and anomalies within that method, and
reliance on observable phenomena (which that methods tends towards) will
end in tears.

Well I think its a central point of the method that for something to
exist it should be observable, either directly or through its effect on
other things.


I'd add that the good ol' Wiki is not always accurate - I've put a
couple of things up that have never been challenged or edited.
Frightening :-)

Rob

Its an odd think Wiki, I don't think its any less accurate than most
other sources, its just its inaccuracy is obvious, where most texts as
they have no means of being changed are assumed to be fixed in stone.
Its at least as accurate as any history book, it works on the basis of
the truth being what enough people agree it is :-).

--
Nick

Advice: Amp building
 

"Wally" wrote


I disagree with the notion that putting together a system with totally
different aspirations is an unhelpful paradigm. The aim isn't audiophonic
perfection for its own sake, but some sort of emotional response to music.
The 'accuracy' approach is one that people use to attain the said
response,
and it works for many. However, it should be pretty obvious that, if Keith
gets the emotional thing he's after from his kit, then it follows that the
accuracy approach cannot be the only one.


Quite. There's no such thing as true 'accuracy' when you are playing
recorded music in your own home - especially if you play LPs, when even a
cartridge change can result in significant alterations to the 'sound'. After
that, room acoustics and speaker colouration throws everyone else into the
same boat....

I don't try to kid myself about getting 'accuracy' in the 'signal
amplification' sense, I leave that to the designers and manufacturers - I am
only concerned with what I consider to be *natural* and seek to get a sound
that grabs and *keeps* my attention. For instance, one of my main complaints
about CD is nothing to do with what it may sound like but that, invariably,
I lose concentration and 'wander off' when one is playing.

IOW, after the occasional, initial impact of a 'clean and dynamic' sound
from some CDs, I find they quickly become quite *boring* - and the
'unnatural' length of a CD doesn't help....!!

(Like: CDs? Oh, they're fine, but I couldn't possibly manage a whole
one....!! ;-)

Prompts the question: Is there anyone here who can *really* listen to a
whole CD from beginning to end?

(Promps also the thought: Anyone who listens to a record is missing the
point - they should be listening to the *music*!! ;-)

Advice: Amp building
 

"Rob" wrote


I don't think Keith has a different set of aspirations, although I do
think his approach is unorthodox and out of the box (so to speak). It's
certainly changed my way of thinking about reproducing music.


Rob, LPs, triodes, and 'horns' may well go against the grain in ukra but out
in the Real World there are a *lot* of people who are thundering along the
same route.....

(Awaits inevitable response that the trode/horn/vinyl set will represent a
small percentage of the 'audio community' when compared with the hordes
playing Chav Disks on supermarket DVDPs....)

Advice: Amp building
 

"Don Pearce" wrote


Waddya mean hassle? You'd have been bored silly. Within a couple of
days you'd have been in the shed bolting a steam engine into your lawn
mower. :-)



No need - there's nothing wrong with the one that's already on it! ;-)

Advice: Amp building
 

"Don Pearce" wrote


It all revolves around the use of English, when it comes down to it
really, doesn't it? For me the word better in the context of a
reproduction system has an objective measure to do with comparing what
comes out with what goes in. For you it is just another word for
preferable. We ain't gonna agree here, are we?


Nope! :-)

It's the same with 'accurate' - that means *sounds right* to me, AFAIAC it's
got bugger-all to do with 'distortion figures'...!!



OK. What do we try next - different flavour ice cream??

:-)


Well, OK. Provided they are from Marine Ices opposite the Roundhouse.
They've been there about fifty years, make their own and they are
incomparable. Sorry, that means we can't compare them, I think ;-)


A sort of small 'high end, cottage industry' manufacturer that renders the
cheap, mass-produced stuff somewhat bland and uninspiring by comparison,
then....???

:-)