Audio, hi-fi and car audio - how good are class D amplifiers?

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Pickled onions (was Fan noise (was: how good are class D amplifiers?))

"Arny Krueger" wrote in message
. ..
"Tony" wrote in message
. uk

You will have to find out if the main problem is the
noise of the air turbulence from the fan or whether the
fan is making the case vibrate.

Easy enough to do, as the related noises sound vastly different.

Dedsheet and similar
damping sheets (there are a lot out there) will only work
on the case vibration and my guess is it is probably the
other.

IME the most profitable route is to look at the fan itself.

Vibration is usally caused by a fan that is out-of-balance or spinning
too fast or both.

Air turbulence noise is caused by a fan that has badly-designed
blades, or is spinning too fast or both.

It's easy enough to find fans that turn slow and have well-designed
and well-balanced rotating parts.

Test by pressing soft things on the outside of
the case to reduce the vibration - if that reduces the
noise then damping sheet will help.

After you get a good fan, any remaining vibration is usually best
first addressed by compliant mounting of the fan.

You can reduce noise
from the air movement by making the air pass through a
tunnel lined with sound absorbing material,

Good work if you have space for it.

of course
wide enough not to reduce the air flow. If you have to
bend the tunnel to fit it in, so much the better.

There's a lot to be said for simply parking the computer as far away
as possible and investing in longer cables for the display, keyboard
and mouse. USB-connected drives can address the problem of mounting
removable media if you do that a lot.

Hello, the stupid clod's totally lost it now - 3 posts ago this was
about a noisy DVD Recorder, now it's a *computer*?? (How can anybody
take this clown at face value??)

How do you like your pickled onions, Arny - with or with cloves...??

how good are class D amplifiers?

"Arny Krueger" wrote in message
. ..
"Keith G" wrote in message

"Arny Krueger" wrote in message
. ..
"Serge Auckland" wrote in
message

I think that with electronics, it is pretty much
impossible to get it wrong if you buy on the figures,
*provided* that you understand what the figures are
telling you *and* that the published figures are
reliable.

Right - that's the same think we've been trying to
explain to Keith and his fellow loons for a dog's age.

Loon?

I get *cloned* - you get what?

I get sick of your habitual lying, Keith.

I usually find people who play the 'liar' card have got summat to hide
themselves - what do you think I've lied about Arny? Anything'll do, so
I can make you look a **** - I have *never* lied about anything in this
newsgroup and precious little elsewhere in my life - a) I don't need to,
b) I couldn't/can't be arsed...

I bought my last 4 sets of speakers either unheard, or
heard and thought they sounded pretty poor in the demo
room.

Add them to the 600 power amps for DBT-ing you mentioned
the other day ...

In what alternative universe was that, Keith?

I dunno I wasn't there, you tell me - Detroit Wheeltappers and Shunters
HiFi Club or summat...??

(Some bull**** that's already been tossed by my mental filing system,
anyway...)

how good are class D amplifiers?

In article , Keith G
wrote:

"Jim Lesurf" wrote

e.g. Despite Sony being a regarded name I recently tried a DVD
recorder from them. It had a cooling fan that was so loud that it was
distracting when listening to dialogue on items recorded. This is
absurd and needless, yet when I asked a local Sony center their
reaction was 'they all do it'. They seemed not to think it was a
problem, and clearly had no idea that quiet fans can be bought.
Perhaps they think everyone is too busy looking at the pictures to
notice the sound of a helicopter accompanying it. ;-

Given your supersensitivity to noise ('rifle shots' on vinyl for
example) I can see it would be a problem, but the harsh reality is that
even SS/digital creates heat and noise - the computer I am using right
now is really very noisy but it doesn't stop me using it for audio. The
trick is to 'tune it out', 'drown it out' or just stop noticing it!

I've found that the 'trick' is to ensure that the equipment is silent. i.e.
produces no mechanical noises you can hear in use. This is simple enough.

I guess DVD players/recorders are not designed to be too close in use
(more 'over by the telly' ?) - perhaps you got a bad 'un or you have
sited the device badly where it runs hotter than necessary?

In the case I referred to the Sony's fan was audible in the hallway about
five metres from the door to the room.

The above is nothing to do with amps per se. But it shows that some
companies end up being run by suits, and have development engineers
who just produce what they are told by the suits and go home with
their paychecks. The spec says nothing about the fan not making a loud
noise, so this cheap one is fine...

A development engineer who can't deliver the spec. required by his
employers is looking at a career change, at the very least...

That is why they, and their firm, sometimes end up producing poorer
products than previoiusly, and relying on a large ad budget.

I've briefly worked for large firms as well small ones. I've also had
dealings with many over the years. It has seemed clear enough to me
that oncw a firm becomes large and 'established' the people inside it
tend to focus on 'getting on' within the firm on the basis of their
dealings and behaviours 'internally'. The mere customers are forgotten
as they don't do any hiring, firing, promotion, pay assessments, etc.

The advantage of a small firm is that it easier for everyone to see
how the company is doing. They can see the goods being dispatched, and
any that come back. If an item didn't work, it is clear to all who
may be responsible, and all are affected if sales drop.

I've also repeatedly witnessed companies who bring out 'new' products
distinctly worse than the ones they'd made a year or two before.
Different suits and a different R&D team. No internal communications.
No clue. The relevant suits and engineers are often isolated from the
public and getting contact with them is almost impossible in practice.

I think that one can be safely put down to 'market forces at work in the
context of the new, cheap Digital Era' - witness the recent decline in
quality and ultimate disappearance of the Technics brand...

Nothing to do with 'digital era'. I'm old enough to recall the same kinds
of behaviours in the 1960's. 70's,... and with some products which were
nothing to do with audio or electronics.

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

how good are class D amplifiers?

In article , Arny
Krueger
wrote:
"Jim Lesurf" wrote in message

e.g. Despite Sony being a regarded name I recently tried a DVD
recorder from them. It had a cooling fan that was so loud that it was
distracting when listening to dialogue on items recorded. This is
absurd and needless, yet when I asked a local Sony center their
reaction was 'they all do it'. They seemed not to think it was a
problem, and clearly had no idea that quiet fans can be bought.
Perhaps they think everyone is too busy looking at the pictures to
notice the sound of a helicopter accompanying it. ;-

I find no logic to the noise levels of DVD recorders. I have a
Philips/Magnavox at home that is as quiet as a mouse (no fan) and a
Philips at church I bought a few months later that has a fan and is
noisy. I just bought a RCA with a hard drive in addition to the DVD
burner, and it is smaller, cooler, and has no fan.

My experience thus far is similar, in that it seems that all kinds of
details of DVD videorecorders varies in an almost totally unpredictable
way. Mostly in terms of properties which no magazine reviews (in the UK)
ever seem to mention.

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

how good are class D amplifiers?

"Keith G" wrote in message
...

"Arny Krueger" wrote in message
. ..
"Keith G" wrote in message

"Arny Krueger" wrote in message
. ..
"Serge Auckland" wrote in
message

I think that with electronics, it is pretty much
impossible to get it wrong if you buy on the figures,
*provided* that you understand what the figures are
telling you *and* that the published figures are
reliable.

Right - that's the same think we've been trying to
explain to Keith and his fellow loons for a dog's age.

Loon?

I get *cloned* - you get what?

I get sick of your habitual lying, Keith.

I usually find people who play the 'liar' card have got summat to hide
themselves - what do you think I've lied about Arny? Anything'll do,
so I can make you look a ****

OK, time's up! Total lack of response noted - you have already made
yourself look a ****, Arny....

how good are class D amplifiers?

"Jim Lesurf" wrote in message

In article
, Arny
Krueger
wrote:

There's nothing wrong with wondering whether or not a
full set of conventional measurements are a reliable
guide to sound quality in normal listening. It is a
question that has been answered again and again,
affirming the idea that a full set of conventional
measurements are a reliable guide to sound quality.

Alas, the problem seems to be that many 'reviews' not
only fail to make appropriate measurements. They also
fail to give any explanation of their meanings and what
can be drawn from them. Instead the 'review' has purple
prose extolling the writer's impressions about a system
and room the readers will never use.

Precisely. Most contemporary consumer audio reviews appear to be written by
people whose greater strength is journalism, not engineering or any other
form of science. And that's the mainstream press. When you get into high
end audio, you find reviewers whose day job involves homeopathic medicine or
TM.

how good are class D amplifiers?

"Arny Krueger" wrote

Precisely. Most contemporary consumer audio reviews appear to be
written by people whose greater strength is journalism, not
engineering or any other form of science. And that's the mainstream
press. When you get into high end audio, you find reviewers whose day
job involves homeopathic medicine or TM.

One wonders what is going through his mind when he posts this sort of
thing to a UK newsgroup - unless he gets and reads UK audio
magazines...??

(Homeopathy...??)

how good are class D amplifiers?

"Jim Lesurf" wrote in message
...
In article , Keith G
wrote:

"Jim Lesurf" wrote

e.g. Despite Sony being a regarded name I recently tried a DVD
recorder from them. It had a cooling fan that was so loud that it
was
distracting when listening to dialogue on items recorded. This is
absurd and needless, yet when I asked a local Sony center their
reaction was 'they all do it'. They seemed not to think it was a
problem, and clearly had no idea that quiet fans can be bought.
Perhaps they think everyone is too busy looking at the pictures to
notice the sound of a helicopter accompanying it. ;-

Given your supersensitivity to noise ('rifle shots' on vinyl for
example) I can see it would be a problem, but the harsh reality is
that
even SS/digital creates heat and noise - the computer I am using
right
now is really very noisy but it doesn't stop me using it for audio.
The
trick is to 'tune it out', 'drown it out' or just stop noticing it!

I've found that the 'trick' is to ensure that the equipment is silent.
i.e.
produces no mechanical noises you can hear in use. This is simple
enough.

Sure. I missed the word 'tried' (above) and read your post as though you
were stuck with the machine - otherwise my suggestion would simply have
been 'get rid'..!

I guess DVD players/recorders are not designed to be too close in use
(more 'over by the telly' ?) - perhaps you got a bad 'un or you have
sited the device badly where it runs hotter than necessary?

In the case I referred to the Sony's fan was audible in the hallway
about
five metres from the door to the room.

And if I had known that, I would have said 'get rid' anyway....

I've briefly worked for large firms as well small ones. I've also had
dealings with many over the years. It has seemed clear enough to me
that oncw a firm becomes large and 'established' the people inside it
tend to focus on 'getting on' within the firm on the basis of their
dealings and behaviours 'internally'. The mere customers are forgotten
as they don't do any hiring, firing, promotion, pay assessments, etc.

The advantage of a small firm is that it easier for everyone to see
how the company is doing. They can see the goods being dispatched, and
any that come back. If an item didn't work, it is clear to all who
may be responsible, and all are affected if sales drop.

The disadvantage of small firms these days is they have to take washing
to stay afloat - witness Ruark and their (seemingly) numerous
'distributorships' (Tivoli, Vincent, XLO)...

I think that one can be safely put down to 'market forces at work in
the
context of the new, cheap Digital Era' - witness the recent decline
in
quality and ultimate disappearance of the Technics brand...

Nothing to do with 'digital era'. I'm old enough to recall the same
kinds
of behaviours in the 1960's. 70's,... and with some products which
were
nothing to do with audio or electronics.

I disagree and think that the (relatively rare) problems with audio kit
these days mostly stem from people's high expectations for very little
money - which is a direct result of the widespread availability of
ludicrously cheap 'digital' equipment, but there you go....

how good are class D amplifiers?

"Keith G" wrote in message
...

The disadvantage of small firms these days is they have to take
washing to stay afloat - witness Ruark and their (seemingly) numerous
'distributorships' (Tivoli, Vincent, XLO)...

Make that *take in* washing....