In article ,
Arny Krueger wrote:
My experience too. The ProAc Response D15s I bought a year ago
sounded very different to the demo pair for about the first hour of
operation but settled in to the familiar sound after the first day or
so. Some of that may have been my ears/expectations but not the
first 60 minutes.

It's so boring watching true believers pile onto each other with more
ignorance and error.

I'm willing to accept it's *possible* for a speaker to change slightly
with use. However, I'd expect a decent maker to do this at the factory
before final quality check if it is a real issue.

--
*Nothing is foolproof to a sufficiently talented fool.

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

In article , Keith G
wrote:

[big snip :-) ]

Be interesting to see if Jim comments on your lack of snipping or
whether he'll just comment on mine here....???

Well, Keith, as I've just tried to explain in a posting in the relevant
thread. The real point I was trying to make was prompted by the *reason*
you gave for not snipping. I was just simply trying to remind you that many
people may wish to read your own postings and you may unintentionally
incovenience or irritate some of them by reacting as you did. Thus my
comment was really intended to be helpful, not critical.

Above said, I am not the usenet police. So when you or others fail to snip,
that's your choice. :-)

And, once again, if what I wrote irritated you, then I apologise as that
was not my intention.

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

"Chris Morriss" wrote


The only things in my experience that change their sound in the first few
days of operation are loudspeakers. (And then not by much).


It may come as a surprise to a few here, but the minute you start to use
*anything* in this world it's 'physical characteristics' start to change and
it starts to wear out....

Some amps' frequency responses can alter during warm up. Whether this is
a reflection of poor design or the designer's intent is another matter.

I'd be interested to know which models do this, and by how much, and at
what frequencies, this change occurs. Not something I have encountered so
far as I can recall.

It's an Alchemist Kraken integrated -
http://www.alchemisthifi.info/ranges...pd6_integrated
_amplifier.htm. It's a class A amp so runs hot (I don't know how much the
fact that the room temperature is 20 or 25 degrees effects an amp that
"idles" at about 55 degrees). I have noticed the same changes on different
examples of the same amp though, in different environments and with
different speakers. Recently I found an old review of the amp which actually
stated that the amp's frequency response fluctuated for several hours before
settling down -
http://www.alchemisthifi.info/ranges...integrated-rev
iew-hifichoice.jpg - I presume that this result was gathered through
measurement.

One of my favourite amps sounds *very* different when first powered up,
compared with when it's hot, to the degree that a demonstration of it
when cold would not impress me whilst, when warm, I love it.

Again, I'd be interested to hear the details.

See above. Like I say, I don't mind the fact that this happens, nor the fact
that, on paper the amp is noisy or gives "distortion", as I like the amp
more than the modest inconvenience of permenant power-up.

I was at the hifi show in Manchester last week and overheard Eric Kingdom
from Sony talking about the digital Sony amps and talking about the sound
being "unusual" to some people because of the lack of distortion introduced
between source and speaker. He made the point that, what a lot of people
refer to as "musicality" was just colour and distortion introduced by amps.
I felt that this was probably right, but it didn't make me prefer the Sony
amp.

A lot of the talk from some posters in this NG seems to focus on the wrongs
of such distortion, that such deviances are down to poor design or the
delivery of an unnatural performance, that this doesn't reflect the truth of
the recording. To me this argument, although interesting, doesn't really
bother me. If I like the sound then I like the sound - I make no claim to be
pursuing any reality in my hifi as it isn't and connot be reality, my ears
don't work very well, my room's acoustics don't match the "real thing" etc.
Besides, live performance vary from venue to venue, the instruments used all
colour the sound in different ways and, in my experience, the selection of a
musical instrument will depend on a tonal preference - I certainly found
this when trying out pianos and would chose the one that I liked the sound
of most.

There's no doubt that the Kraken amp is coloured, but that colour is one of
the things that I like about it - I enjoy the music more and so it does what
I've paid for. Even the amp's designer says that the frequency response is
deliberately rolled off early, so it strikes me that this is by design and
therefore not a flaw.

To many, in pure engineering terms - and in pursuit of an ideal of the
truest representation of the source - this may be anathema but, to me, and I
suspect most hifi purchasers who listen before buying, when compared to
other products, I liked its "colour" more.

I have no trouble leaving it on, so this isn't a problem for me. While I
may be curious as to *why* this is the case, I don't really care that it
is so - I prefer it and that's all that's important.

Well, it does seem like a 'problem' to me as it implies that the
performance will drift about with room temperature, variations in the
music
power changing the temperatures of devices, etc.

This may well be the case - I don't have the means to test such changes,
although I don't perceive the obvious changes once it's up and running
compared with when it is initially powered up from cold.

KH in a recent issue of Hi Fi News did do some measurements that showed
that the distortion levels in some amps vary as they warm up. However
others don't do this. My recollection is that this has been a 'known'
possibility for decades. (I certainly worked on it when developing over 20
years ago!) Hence such things should in general be removable by correct
design in my experience. If the set sounds 'better' when 'warmed up' then
I'd prefer the design to give the 'better' performance almost from the
instant of switch-on. Not to have to leave the set on for a long time
first. Partly as this would be a minor irritation. Partly as, to me, it
seems like a sign that the designers have not investigated and tackled the
problem.

I don't know if this is true. My favourite amp isn't perfect - it hums a
little, but I don't mind because I don't hear that when the music's playing.
I'd be even happier if the amp sounded the same from the get go and was
silent when not in use. I seem to recall one manufacturer claiming that,
even when in standby, the power supply is still fed to much of their amps'
cicuitry to keep them "warm" so that they sounded good when fully powered
on. I thought that this was inefficient at the time but, compared with
leaving a class A amp on 24/7 it's probably a sensible compromise (if it
wasn't bull****!)

Slainte,

Jim

My new Cambridge Audio amp and tuner both carry instructions that
the
unit should be run continuously (playing music) for 36 hours "to
get
it performing at its best".

Does anyone know what such 'running in' is supoposed to do?

Is it running in, or just warming up?

My last two sets of speakers definitely "ran in" - in different ways;
the Rogers LS4as started off bright and thin, and filled out, whereas
my
Monitor Audio Silver 8is started off dull and perked up.

Electronic components also improved over (a much shorter) time, but
they
also do the same thing if they're unplugged for a few days. So much
so
that I've given up unplugging my amplifiers when I go on holiday, and
I
used to leave my old CD-player switched on all the time (the new one
had
a standby mode).

Quite why things should take longer to warm up than they do to get
physically warm, I'm not sure. No doubt someone will reply in a
minute
to say that good equipment doesn't do that, and it's just a figment
of
my imagination!

Can't really comment on your imagination. :-)

However my experience is as follows:

That on some occasions the properties of electrolytic capacitors will
vary
depending upon the use history and the quality of the caps. However my
experience is that leaving an amp unused for a few days or weeks has no
audible effect in general due to this.

Similar comment to the above about some connections. If the connections
are
not decently ohmic they may be affected by use, or by the unit being
left
unused - particularly somewhere cold/damp.

Apart from the above, some components take a while to warm up. This may
affect the bias conditions in gain devices a little. You may also find
that
a mains transformer takes a while to warm up, and this can affect the
amount of mechanical 'buzz' it produces.

In general, though, I'd expect a unit to warm up and not really be
noticably different quite soon after being switched on, and not mind
being
left off for many days. There are exceptions, but I'd tend to see them
as
signs of questionable design, flaws, or poor storage/conditions of use.

FWIW at one time I used to do things like shove the amp I was working
on
into the fridge overnight so I could check out the effect of a 'cold
start'
the next day. This can show up problems. However my experience was that
decently designed amplifiers should not be bothered. A tuner *might*
suffer
some tuning misalignment if the tuning elements are temperature
sensitive.
A speaker may well be affected as the suspension stiffness, etc, may be
affected by temperature. The field produced by a permanent magnet is
also
affected by temperature - but this should be a small effect for such
modest
temperature changes.

However, generalisations apart, I've no idea why Cambridge Audio would
make
such a statement. Ask them, and see if their explanation makes any
sense!
:-)

It is quite possible to perceive changes as time passes for all sorts
of
reasons. Our hearing changes during the day, and as we wake up,
eat/drink,
are distracted/alarmed/bored, etc, etc. Also the air changes its
acoustic
properties a little as it changes temperature and humidity, etc. Also
the
level of background 'noise' can also affect perception. Listening to
sounds
also tends to cause our hearing to alter/adapt. Hence we may well hear
a
difference if we turn on a system and play the same music a few times
at
different times during a day, or from one day to another. But this does
not
have to mean that the equipment is changing its performance.

Slainte,

Jim

Some amps' frequency responses can alter during warm up. Whether this is
a
reflection of poor design or the designer's intent is another matter.

One of my favourite amps sounds *very* different when first powered up,
compared with when it's hot, to the degree that a demonstration of it
when
cold would not impress me whilst, when warm, I love it.

I have no trouble leaving it on, so this isn't a problem for me. While I
may
be curious as to *why* this is the case, I don't really care that it is
so -
I prefer it and that's all that's important.


Be interesting to see if Jim comments on your lack of snipping or whether
he'll just comment on mine here....???

I wasn't aware that this was an issue and don't really care )

--
-----------------------------------------------------------------
Please include this message in your reply.
"Robert" wrote in message
om...
Kalman Rubinson wrote in message
. ..
On Mon, 25 Oct 2004 21:56:38 +0100, Ian Bell
wrote:

The thing is that it most likely was not the amp that changed
throughout the
day but your perception.

Of course but so many people just will not understand.


Of course, I bet that is why they instruct you to run in the new
equipment by playing music on it for 36 hours. it's not really to run
in the equipment; it's to runn in the buyer. I imgaine that they
have reduced the number of returns they get from people who find that
they 'don't like the sound'.

This is true and people do grow to appreciate things more with time. However
that isn't the whole story. Speakers definitely DO change when being run in
and, as I mention above, some products (not necessarily new purchases
either) will sound different when warm compared with when cold.

Human perception, changing environments, psychology, the brain, the ears and
actual physical changes in the product all play a part.

I remember once testing loudspeakers on a system where you could
switch instantly between them. I found that if you listened to one
pair for too long then the others all started to sound inferior when
you tried them even if they were in fact much better speakers.

Have you tried comparing two pairs of the same model, one "burnt in" and one
not?

Robert

Arny Krueger wrote:
My experience too. The ProAc Response D15s I bought a year ago
sounded very different to the demo pair for about the first hour of
operation but settled in to the familiar sound after the first day or
so. Some of that may have been my ears/expectations but not the
first 60 minutes.

It's so boring watching true believers pile onto each other with more
ignorance and error.

I'm willing to accept it's *possible* for a speaker to change slightly
with use. However, I'd expect a decent maker to do this at the factory
before final quality check if it is a real issue.

Then you should also expect to pay more for that speaker in the shop.

"Keith G" wrote in message
...

"Chris Morriss" wrote


The only things in my experience that change their sound in the first
few
days of operation are loudspeakers. (And then not by much).


It may come as a surprise to a few here, but the minute you start to use
*anything* in this world it's 'physical characteristics' start to change
and
it starts to wear out....

If we observe a speaker and measure its performance then, in doing so,
aren't we altering its behaviour ;o)

On Wed, 27 Oct 2004 19:40:09 +0100, "JustMe" wrote:
This is true and people do grow to appreciate things more with time.

And they never appreciate them less? What we are dealing with is
simple adaptation.

some products (not necessarily new purchases
either) will sound different when warm compared with when cold.

Warm up, particularly of powered devices, is not the same thing as the
'running in' proposition.

Human perception, changing environments, psychology, the brain, the ears and
actual physical changes in the product all play a part.

To wildly varying degrees.

I remember once testing loudspeakers on a system where you could
switch instantly between them. I found that if you listened to one
pair for too long then the others all started to sound inferior when
you tried them even if they were in fact much better speakers.

Adaptation at work.

Have you tried comparing two pairs of the same model, one "burnt in" and one
not?

Yup.

Kal

"JustMe" wrote in message
...
"Keith G" wrote in message
...

"Chris Morriss" wrote


The only things in my experience that change their sound in the first
few
days of operation are loudspeakers. (And then not by much).


It may come as a surprise to a few here, but the minute you start to use
*anything* in this world it's 'physical characteristics' start to change
and
it starts to wear out....

If we observe a speaker and measure its performance then, in doing so,
aren't we altering its behaviour ;o)


**** Nose. I just *listen* to mine.... ;-)