Hi all,

To the best of my knowledge, almost all amplifiers' specification used to
state the Bandwidth to be on the average 20hz to 20khz. There were some,
such as Chord and a number of tube/valve amplifier with rated full power
bandwidth upto 100khz. Lately, i.e after SACD and DVD -A many amplifer now
state bandwidth up to 100Khz.

My question, did any significant design or circuit changed to meet the above
20khz in the last 5 years or is it mere renumbering in the specs?

The same happened in the frequency response specs. It used to be 40 or more
to 20KHz. Now all of sudden the speaker manufacturers are promoting speakers
meeting the new formats reqirements and stating max upto 35khz and more.
Renumbering or redesign?

Over to you guys...

In the case of amplifiers, it is a bit of both as the technology has
been there, so some makers may have been conservative or felt the need
to keep it reasonably useful sounding by limiting their measurement to
20khz. Another reason is that they may not have been able to measure
higher with their test gear and felt that was good enough as did the
rest of the buying public evidently. Really until speakers could
produce higher frequencies, it was (pardon the pun) mute. In the case
of modern loudspeakers, there has been a significant increase in
implementation of the materials and design to allow frequency
extension and that has definately made it more attractive for
amplifier manufacturers to either redesign their amps or simply
remeasure with more accuracy to get the higher numbers. As a case of
how both the technology has progressed and how the ability to quantify
it has diminished, Jacques Mahul of JM Lab has said of the limits of
their new beryllium tweeter that they state its response to be flat
out to 40khz, but that it could be much higher than that. That is as
high as they can measure accurately with their microphones. The output
of amplifiers can be measured on equipment without having to use
microphones, so that is quite different. Speakers have an acoustic
output and that is what has to be measured there as it is their whole
point.
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Chelvam" wrote in message
...
Hi all,

To the best of my knowledge, almost all amplifiers' specification
used to
state the Bandwidth to be on the average 20hz to 20khz. There were
some,
such as Chord and a number of tube/valve amplifier with rated full
power
bandwidth upto 100khz. Lately, i.e after SACD and DVD -A many
amplifer now
state bandwidth up to 100Khz.

My question, did any significant design or circuit changed to meet
the above
20khz in the last 5 years or is it mere renumbering in the specs?

The same happened in the frequency response specs. It used to be 40
or more
to 20KHz. Now all of sudden the speaker manufacturers are promoting
speakers
meeting the new formats reqirements and stating max upto 35khz and
more.
Renumbering or redesign?

Over to you guys...

The whole purpose of high sample rate digital is to improve the high
end (4 Khz - 18 Khz) that is audible to the human ear.

as sampling rate increases so does audible resolution in the higher
frequencies (dogs don't listen to records).

Don't fall into the trap of thinking that your amp/tweeter has to be
flat up to 50 or 100 KHz to fully appreciate the benefits of high
sample rate digital.
This is just hype that manufacturers are selling you in order for you
to buy their amps based on published specs and not sound.

a .50 cent op-amp can have .0001 THD and 2 MHz bandwith and still
sound bad.

The number wars have created some awful side -effects in hi-fi in the
past and every time a new technology comes out the marketing people
and sales staff take advantage of consumers that aren't prepared
technically to understand what is ideal and what is not.
learn to trust your EARS and you'll always be one step ahead.
It should be said that any amp that cuts off at 20 KHz has got to have
some bad engineering faults, and probably is not going to be as stable
and clean as an amp that goes to 100 KHz without resorting to feedback
or trickery.
Watch out for super bandwith speakers and amps that MAY come out in
the future. Manufacturers will probably try to get in on the fad even
at the cost of making inferior sounding components that reach the high
frequency spec.

maxdm wrote:
The whole purpose of high sample rate digital is to improve the high
end (4 Khz - 18 Khz) that is audible to the human ear.

as sampling rate increases so does audible resolution in the higher
frequencies (dogs don't listen to records).

According the Nyquist theorem, what increases is the ability to reproduce
higher and higher frequencies. The audible 'resolution' of material in the
4-18 kHz range does not increase when sampling rates climb above
twice the top of that range (leaving aside the need to account for
filtering).


Don't fall into the trap of thinking that your amp/tweeter has to be
flat up to 50 or 100 KHz to fully appreciate the benefits of high
sample rate digital.

Don't fall into the trap that sample rates above 96 kHz
are necessary for digital recording. (See Dan Lavry's work as a reference).



--

-S.
Why don't you just admit that you hate music and leave people alone. --
spiffy

You are entirely missing the boat here. It has nothing to do with
digital sampling. We are talking about analog bandwidth and
loudspeakers/amplifiers. Digital implementation will have to improve
to take full advantage of these analog improvements. It's just a
matter of time and they will as there, as there is a desire to be able
to reproduce live sound without compression or limitation as forms of
distortion. The manufacturers that are at the leading edge of this
curve are producing better products. Just because a 20k brickwall
filter cannot fully take advantage of it or someone cannot fully
appreciate it due to their hearing ability does not make it any less
an improvement. So in time, there will be better digital products as
well to complete the chain.
Don't assume that someone is always trying to rip you off just because
they would like you to pay them for their efforts. There are many very
smart consumers and for a maufacturer to get ahead, it is in their
best interest to produce a better product. It's capitalism and it's
market-driven as well as just the desire of the engineers to produce
the best product that is possible. There is also still something to
say about pride in one's work and in the benefit of one's product to
the general good. I'm not going to say that everyone will appreciate
it or care, but to those that put a priority on music in their homes,
higher fidelity and performance products will always be welcome.
There is quite a bit written on the subject of the effect of higher
frequencies on the lower frequencies (those that you call audible) and
their relationships when separated. You can choose to find the
resulting products useless to you, but not to others without similar
research and evidence of your own. It is interesting that you can find
an amplifier defective that will not produce clean signals above
20khz, but do not have a problem with digital devices or loudspeakers
that cannot. It would seem to be a matter of course that developments
to improve the linearity of the entire chain to be advantagious. We
could debate the relative value of the improvements "unitl the cows
come home", but the fact remains that they are just that,
improvements.
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"maxdm" wrote in message
news:Sn_yc.25653$eu.20164@attbi_s02...
The whole purpose of high sample rate digital is to improve the high
end (4 Khz - 18 Khz) that is audible to the human ear.

as sampling rate increases so does audible resolution in the higher
frequencies (dogs don't listen to records).

Don't fall into the trap of thinking that your amp/tweeter has to be
flat up to 50 or 100 KHz to fully appreciate the benefits of high
sample rate digital.
This is just hype that manufacturers are selling you in order for
you
to buy their amps based on published specs and not sound.

a .50 cent op-amp can have .0001 THD and 2 MHz bandwith and still
sound bad.

The number wars have created some awful side -effects in hi-fi in
the
past and every time a new technology comes out the marketing people
and sales staff take advantage of consumers that aren't prepared
technically to understand what is ideal and what is not.
learn to trust your EARS and you'll always be one step ahead.
It should be said that any amp that cuts off at 20 KHz has got to
have
some bad engineering faults, and probably is not going to be as
stable
and clean as an amp that goes to 100 KHz without resorting to
feedback
or trickery.
Watch out for super bandwith speakers and amps that MAY come out in
the future. Manufacturers will probably try to get in on the fad
even
at the cost of making inferior sounding components that reach the
high
frequency spec.

maxdm wrote:
The whole purpose of high sample rate digital is to improve the high
end (4 Khz - 18 Khz) that is audible to the human ear.

as sampling rate increases so does audible resolution in the higher
frequencies (dogs don't listen to records).


You are confusing bandwidth with resolution. Resolution doesn't increase
with sample rate.

Don't fall into the trap of thinking that your amp/tweeter has to be
flat up to 50 or 100 KHz to fully appreciate the benefits of high
sample rate digital.
This is just hype that manufacturers are selling you in order for you
to buy their amps based on published specs and not sound.


4 sentences later you are stating the opposite

a .50 cent op-amp can have .0001 THD and 2 MHz bandwith and still
sound bad.


What makes you believe this? And which parameter exactly makes that opamp
sound bad? What does the price tag mean in these circumstances?

The number wars have created some awful side -effects in hi-fi in the
past and every time a new technology comes out the marketing people
and sales staff take advantage of consumers that aren't prepared
technically to understand what is ideal and what is not.

What are these awful side effects you are talking about? Seems you are
describing your own situation as a customer.

learn to trust your EARS and you'll always be one step ahead.
It should be said that any amp that cuts off at 20 KHz has got to have
some bad engineering faults, and probably is not going to be as stable
and clean as an amp that goes to 100 KHz without resorting to feedback
or trickery.

But those amps all use feedback, in fact the opamp principle (you mentioned
it) is based on feedback. What would be the trickery?

Watch out for super bandwith speakers and amps that MAY come out in
the future. Manufacturers will probably try to get in on the fad even
at the cost of making inferior sounding components that reach the high
frequency spec.

Now are these speakers superiour or inferiour sounding? Or maybe identical?

--
ciao Ban
Bordighera, Italy

"Uptown Audio" wrote in message
...
In the case of amplifiers, it is a bit of both as the technology has
been there, so some makers may have been conservative or felt the need
to keep it reasonably useful sounding by limiting their measurement to
20khz. Another reason is that they may not have been able to measure
higher with their test gear and felt that was good enough as did the
rest of the buying public evidently. Really until speakers could
produce higher frequencies, it was (pardon the pun) mute. In the case
of modern loudspeakers, there has been a significant increase in
implementation of the materials and design to allow frequency
extension and that has definately made it more attractive for
amplifier manufacturers to either redesign their amps or simply
remeasure with more accuracy to get the higher numbers. As a case of
how both the technology has progressed and how the ability to quantify
it has diminished, Jacques Mahul of JM Lab has said of the limits of
their new beryllium tweeter that they state its response to be flat
out to 40khz, but that it could be much higher than that. That is as
high as they can measure accurately with their microphones.

Doesn't seem likely since good 1/4" measurement microphones have been able
to measure accurately to about 60kHz for many years and I'm sure Focal (the
old name for JM Lab) even in the old days had some good mic's on hand.
Sounds like marketing hype rhetoric to me . . . " Gee our new beryllium
tweeter is sooo good that we don't even know how good it is". That being
said, the inverted metalized dome from Focal was one of the forerunners in
pushing the 20kHz envelope with keeping low end frequency response in check.
A tweeters low end frequency response is more more beneficial than going
extra high!

Since about 7 years or so high frequency response has been highly marketable
mostly because of the magazines saying how "they could really hear that
extra 5kHz etc."

of amplifiers can be measured on equipment without having to use
microphones, so that is quite different. Speakers have an acoustic
output and that is what has to be measured there as it is their whole
point.
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Chelvam" wrote in message
...
Hi all,

To the best of my knowledge, almost all amplifiers' specification
used to
state the Bandwidth to be on the average 20hz to 20khz. There were
some,
such as Chord and a number of tube/valve amplifier with rated full
power
bandwidth upto 100khz. Lately, i.e after SACD and DVD -A many
amplifer now
state bandwidth up to 100Khz.

My question, did any significant design or circuit changed to meet
the above
20khz in the last 5 years or is it mere renumbering in the specs?

The same happened in the frequency response specs. It used to be 40
or more
to 20KHz. Now all of sudden the speaker manufacturers are promoting
speakers
meeting the new formats reqirements and stating max upto 35khz and
more.
Renumbering or redesign?

Over to you guys...

maxdm wrote:
The whole purpose of high sample rate digital is to improve the high
end (4 Khz - 18 Khz) that is audible to the human ear.

Wrong. This, frankly, is a high-end audio myth that is becoming
overwhelmingly tiresome to debunk. If you claim is that the range
of 4 kHz-8 kHz needs to be maintained with findelity, then it was
demonstrated by Shannon and Nyquist well over 50 years ago that
a sample rate of slightly greater double that is both necessary AND
sufficient to represent it with perfect fidelity. The fact that any
number of high-end wonks claim otherwise is loud testimony as to how
far out of touch the high-end audio biz is with the basic principles
of signals and sampling.

I would kindly refer the poster to the works of Shannon, and I would
invite anyone in the high-end biz that claims contrary to that theorem
to first point out the flaws in that theorem with the same rigor it
was formulated in the first place. To date, not a single person has
succeeded, not a single person has come even remotely close.

The purpose of the claim that high sample rate improves the high end
is to promote the new media.

as sampling rate increases so does audible resolution in the higher
frequencies (dogs don't listen to records).

Not below 1/2 the sample rate, it doesn't. It absolutely does not.
If you are claiming the contrary, that constitutes an extraordinary
claim, given the magnitude of effort and the degree of scientific
and mathematical rigor that has been applied to the subject of sampling
50 YEARS before the high-end audio biz ever stuck its toe in that
pool of water. Being thus such an extraordinary claim, I would suggest
that the burden of proof is on YOU to prove that an entire huge body
of work is wrong.

Don't fall into the trap of thinking that your amp/tweeter has to be
flat up to 50 or 100 KHz to fully appreciate the benefits of high
sample rate digital.

When viewed in the context of what IS known about signals and
sampling, and by that we don't mean the paltry, myth- and bunkum-
inspired high-end audio nonsense, but as embodied in, as a start,
Sampling Theorem, this statement simply contradicts the first
one above.

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| Dick Pierce |
| Professional Audio Development |
| (1) 781/826-4953 Voice and FAX |
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