In article , mick
wrote:
On Sat, 23 Oct 2004 09:05:25 +0100, Jim Lesurf wrote:

In article , mick
wrote:


What about old recordings - made using valve studios? You should
*never* play them using ss amps because the sound will be wrong.

For me, the above argument does rather miss the point. In my
experience, one of the main areas of difficulty for valves arises in
the power amp where an output transformer tends to be required in most
designs. Hence it is perfectly possible to use valves in the 'line
level' stages in a chain and avoid these, but doing so does not tell
us what may happen when the end user employs a valve+transformer power
amp.


Fair enough, but surely you have to take into account the fact that when
old recordings were being made the producer wouldn't have believed that
his work could have been opened to so much scrutiny at some time in the
future. He could only work with knowledge of the reproduction equipment
available at that time, if that used valves then he would produce the
recording to sound "right" on valve amps! ;-)

Not quite. Although I note the implication of what you are saying. Namely
that we should listen to pre-mid-1960's recordings on valve kit, but use
solid-state for later recordings or remasterings... :-)

There are a number of points I would make about what you say above.

The first is that when you listen to a variety of recordings you find that
they differ for reasons which - when listening on decent kit - can easily
be assigned to changes in microphone locations, choice of mics, hall/studio
acoustics, etc, etc. Yet when listening in a domestic situation we use the
same setup for listening to this variety of recordings or broadcasts. Hence
we have to be concerned with assessing performance averaged over a range of
recordings and broadcasts that may have been sourced at different times and
in different ways. Some will have used 'valve era' recording kit, some
'solid state era'. (Terms used loosely.)

The second is that the recording will have been made using what those
involved felt was the best kit available to them at that time, and probably
monitored on studio kit that may not share a lot with what people were
using at home at the time. Sometimes those involved may well have done some
check-listening on kit designed to mimic the flaws of 'lowest common
denominator' kit (e.g. transistor radio like for 'pop'). As with the first
point, this means a 'diversity' of assumptions and aims by those creating
the recording/broadcast. That said, my understanding is that those at the
BBC and the main companies who were/are producing 'classical' or 'acoustic'
music tend to assume that the results should be aimed at those using the
best available domestic kit.

Thus in practice we may find it difficult to use guesswork about what
specific kit the producers/engineers thought we might have since this will
change from one recording to another. This was one of the reasons that the
'high fidelity' concept is useful as it gives us an alternative. It allows
us to specify the nominally desirable behaviour of individual kit items in
the chain even when the recordings vary. The idea being that we set a
'target' performance which those recording/broadcasting can have in mind,
and users can employ as a reference point in conceptual terms.

Thus the producers - when aiming for good results for 'classical' and
'acoustic' music - can work on the basis of a defined frequency response,
distortion level, etc, being the 'target assumptions' for the domestic
reply kit. We can then use the same assumption when desiging and using such
kit.

Of course, in indivual cases we can expect to choose to vary from this. For
example, in a room with a given acoustic we might choose to employ speakers
whose response would not be satisfactory in some other room. Or having
chosen a room/speaker arrangement, then use an amp whose response departs
from being 'flat' so as to get an overall response that is closer to what
we would get with a technically flatter system in a room with a flatter
acoustic. (I am picking out frequency response here as it is the easiest
parameter to use as an example.)

The above points are some of the reasons I do feel that 'high fidelity' is
far from pointless.

The other is that my personal experience is that by using amplifiers that
have a flat response, low distortion, etc, and suitable speakers, etc, I
get results which seem to be - in general - superb to me. The result is
that I am often left with the sensation of listening to musicians playing
music I can enjoy. I don't get any sensation of hearing an 'amplifier
sound' or 'speaker sound'. Just the music.

In addition, the sound of the instruments, and the acoustics, and the
stereo image, change from one recording to another. Hence I seem to be
hearing a clear indication of the variations in the preferences/choices of
those making the recording/broadcast, and in the hall/studio acoustics.

Conversely, when I have listened using amps or speakers that have
distinctly unflat or resonant responses, and/or high levels of nonlinearity
I find these perceptions are impaired - although in some specific cases
some recordings sound quite 'pleasing'. My personal preference, though, is
not for a system that does this. It is for what I described in the previous
pair of paragraphs.


The search for "Hi-Fi" is pointless.

This I disagree with.

It means "high fidelity - i.e. it sounds close to the original, so it
can only be judged by someone who heard the original performance live.

Not quite. If you are referring to an item like the amplifiers used in
a domestic audio reproduction system then the 'original' can mean the
signal source pattern presented to the unit. You can then pursue 'high
fidelity' on the basis of trying to get units (or chains of units)
that treat fidelity in this manner.


Yes, you can, but only if you did the mix in the first place. No-one
else knows what was intended to be heard.

No. The point of what I wrote above is that you can compare the input and
output voltage-time patterns of the amplifier *in its use* and see how
similar they are. I do not need to know how a time-varying pattern was
produced. I can use whatever pattern emerges from an LP or CD replay
system. Then observe how that is affected by stages along the chain.

This pattern either represents what the producers wanted me to hear, or it
does not. Their responsibility is to deliver to me a carrier that provides
this pattern. The responsibility of the domestic kit is to take that
pattern and amplify it, etc.

If you wish to make the domestic kit responsible for the failures and
misjudgements of individual recording/broadcast producers, then I would
argue *that* approach was futile - or as you wrote "pointless" for two
reasons.

One being the reason you give. That we can't know precisely what they did.

The second being that even if we did know, the requirements will change
from recording to recording in an unpredictable and uncontrollable manner.

Hence the untility of the 'high fidelity' approach.


The above might mean a decision to deliberately alter the amp so that
its behaviour was engineered away from being "wire with gain", but
using the approach I am describing we would then have a choice, and
might be able to identify imprefections in the source or destination
(e.g. speakers or room acoustics) which might prove a more fruitful
area of attention when an amp that behaved like "wire with gain"
"sounded wrong".


grin Bring back tone controls! lol!

Yes. :-) In fact, my experience is that 'tone controls' if appropriately
designed and used, can be quite useful on occasion. For the reasons I
outline above and in my earlier posting. I find that most of the time no
adjustment is needed, but in some cases I prefer the result if some
adjustment it made. However I am not necessarily talking about the old
baxandall controls. ;-)

However here, once again, the 'high fidelity' acts as a point of departure.
The idea being that the response should nominally be 'flat' but given the
variabilities of recording/broadcast production we do enocounter recordings
where the source response is felt to be unsatisfactory. We can then decide
to apply changes in a controlled manner, but not have to impose the same
changes on all recordings.

I realise that the above is deeply unfashionable amongst audio reviewers,
and may rather upset their ability to use small variations in response as a
basis of 'wine tasting', though... ;-)

Slainte,

Jim

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