I have left your message below in its entirety, Mr. Krueger, because
it seems largely to
consist of random neuron firing on your part. To address and correct
each or every part
of what you say, whether it is relevant or not, is beyond both my
stamina and my time.
To sum up:
1) You claimed to hear program content in the 6Hz region over
headphones at
moderate spls. This is an extraordinary claim, that contradicts the
published
literature on human hearing sensitivity. I pointed that out and
offered an
alternative explanation for your test results.
2) Upon examination of your test procedure, it appeared you were
inserting a high-pass
filter. Prior work (Fincham) indicates that the in-band phase error
due to the filter is
likely to be the cause for you perceiving differences.
3) You agree with me that this is what you were testing for.
4) You agree with my past writing that it is a good thing to eliminate
as many
high-pass filters in the recoridng and playback chain as possible.
5) You would extend this to the loudspeakers.
6) You disgree with me that recordings with content in the 6Hz region
are
very rare. As I have analyzed many recordings and not found many to
have
any infrasonic information, please give examples of such recordings.
Thank you in advance for doing so,
John Atkinson
Editor, Stereophile
---------------------------------------------------
"Arny Krueger" wrote in message
...
John Atkinson wrote:
"Arny Krueger" wrote in message
...
John Atkinson wrote:
"Arny Krueger" wrote in message
...
John Atkinson wrote:
what sound pressure level was required for the 6Hz tone to become
audible? The Fletcher-Munson or Robinson-Dadson curves imply that
6Hz is not audible at normal levels, yet you are saying different.
Please cite a reference that portrays minimum reliably perceptible
acoustic levels for the 5-10 Hz range from Fletcher-Munson
Robinson-Dadson, or any other source.
The sensitivity curves in these data increasingly rise with reducing
frequency to their lower limits. There is no reason to believe the
curves have points of inflection below those limits.
Failure to properly answer a simple question noted. Substitution of a
fact with questionable [relevance] isn't a proper answer.
Furthermore, the two sets of curves that Atkinson cited have vastly
different slopes in the region he is discussing.
http://www.sengpielaudio.com/Fletche...son-Dadson.pdf
Since the curves are so different, it is questionable to me as to whether
they are both accurate, or either is accurate. Neither curve covers the
frequency range being discussed here. This is an odd collection of
evidence
that Atkinson has dragged in!
I think you misunderstood my point, Mr. Kreuger. Whether you take the
earlier Fletcher-Munson sensitivity curves or the more recent research
from Robinson and Dadson, simple extrapolation from these curves
indicates that the human ear continues to lose sensitivity with
reducing frequency.
I reject the necessity of making an either-or choice. I've already shown how
the evidence you've presented Atkinson, is self-contradictory. This is
repeated just below.
... the two sets of curves that Atkinson cited have vastly
different slopes in the region he is discussing.
http://www.sengpielaudio.com/Fletche...son-Dadson.pdf
Since the curves are so different, it is questionable to me as to whether
they are both accurate, or either is accurate. Neither curve covers the
frequency range being discussed here. This is an odd collection of
evidence
that Atkinson has dragged in!
The implication is that by the time you reach
6Hz -- almost two octaves below the 20Hz usually stated as the "limit"
of human hearing -- you would need extraordinary high spls to "hear"
the tone.
Repeating speculation and self-contradictory results doesn't make it fact.
... the two sets of curves that Atkinson cited have vastly
different slopes in the region he is discussing.
http://www.sengpielaudio.com/Fletche...son-Dadson.pdf
Since the curves are so different, it is questionable to me as to whether
they are both accurate, or either is accurate. Neither curve covers the
frequency range being discussed here. This is an odd collection of
evidence
that Atkinson has dragged in!
I never said that I was perceiving 6 Hz tones.
My test reports related to perceiving their reduction, absence or
some by-product of common means of eliminating or reducing them.
As you seem to be saying that you could hear the difference with and
without 6Hz content using headphones at moderate levels, all I am
doing is pointing out that it would seem unlikely you are actually
"hearing" the 6Hz content in light of the published data on the
subject.
I never said that I was perceiving 6 Hz tones.
My test reports related to perceiving their reduction, absence or
some by-product of common means of eliminating or reducing them.
As I conjectured, perhaps you are detecting the audioband
action of the high-pass filter?
I never said that I was perceiving 6 Hz tones.
My test reports related to perceiving their reduction, absence or
some by-product of common means of eliminating or reducing them.
If so, how can you report perceiving 6Hz tones using headphones?
I never said that I was perceiving 6 Hz tones.
My test reports related to perceiving their reduction, absence or
some by-product of common means of eliminating or reducing them.
With respect Mr. Krueger, you did appear to be saying just that. On
multiple occasions.
Since you can't quote me saying such a thing, this would be a false claim on
your part, Atkinson.
You also criticized Scott Wheeler (S888wheel) for
saying the opposite.
Since you can't quote him saying such a thing, this would be a false claim
on your part, Atkinson.
Well yes, now you are saying that, which in turn allows for the fact
that you actually agree with me that it is perhaps the action of the
filter you are perceiving, not the presence or absence of 6Hz content.
That's what I said, isn't it?
As I asked:
Was this a double-blind test involving a high-pass filter?
Yes.
Which is my point. That the high-pass filter is also a variable in
this test and might well be the source of the identification you
report. Laurie Fincham, then with KEF, did some blind tests in the
early 1980s that such filters produced audible effects.
Again, you've missed the point, Atkinson. With modern technology, much of
the high-pass filtering present in modern audio systems is not necessary. If
this filtering has an reliably-perceptible audible effect, then we have to
ask why it is being tolerated.
If so, then isn't it more likely that the test was detecting the
audio-band phase error of the filter, rather than the presence of
infrasonic (6Hz) information?
The filter in question is known to be a [reasonably] precise
[implementation] of the type of filter it is stated to be.
So what? My conjecture doesn't necessarily depend on the
implementation of a high-pass filter, only that one be used.
That's a possibility, as I've said a number of times. I'm glad to see that
you are coming around to agreeing with me when I said a number of posts ago:
I never said that I was perceiving 6 Hz tones.
My test reports related to perceiving their reduction, absence or
some by-product of common means of eliminating or reducing them.
If you
really wanted to perform a test on the audibility of content in the
6Hz region, you would need to compensate for the filter's audio-band
phase error, surely?
Or plan "B", implement the filter without phase shift. That seems to be a
more feasible way to do it, given the availble tools.
As I point out in a recent post, these filters are probably less
audibly damaging than the actual filters that are built into most
audio systems, particularly audio equipment based on tubes or audio
equipment created for the purpose of vinyl playback.
I agree. As I have written in Stereophile, the recording-playback
chain consists of cascaded high-pass filters. Which is why it is very
rare for recorded music to contain high levels of content below 30Hz,
let alone 20Hz.
Neverthless, there are numerous commercial recordings with substantial
content that extends well below 20 Hz, there are numerous audio systems that
are capable of reproducing this content, and the content is reliably
perceptible. However since this content is infrasonic, it is not perfectly
technically accurate to call it "audible".
The purpose of my test is to show that infrasonic filtering has reliably
percptible effects that change the quality of sound from its natural or
intended state. Since high fidelity is about reducing or eliminating
reliably percptible effects that change the quality of sound from its
natural or intended state, unecessary infrasonic filtering should be
avoided. This naturally results in creating audio systems that have response
in the infrasonic range.
It is generally agreed that recordings tend to lack a sense of liveness that
is present in live performances. Various enhancments have been proposed, in
the interest of restoring this sense of liveness. Regrettably, some of these
proposed enhancments, such as extending the bandpass beyond 20 KHz don't
seem to have any reliably perceptible effects. Extending response below 20
Hz is well known to have reliably perceptible effects. Therefore I find it
strange to be arguing for preservation of infransonic content present in
live music, against the editor of a high end audio magazine and another
audiophile.