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 relvance 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!

Atkinson seems to be unwilling to believe that there may be any differences
in human perception between the sonic and infrasonic ranges.

There is a long-standing tradition of calling the sonic and infrasonic
ranges two different things. I know he's not ignorant of this convention. I
don't know why he wants to ignore it.

Since he can't provide a simple answer to a simple question about the curves
he cited, perhaps Atkinson could at least try to make some
intelligent-sounding noises about why the sonic and infrasonic ranges are
called two different things.

there is evidence that the absence, reduction or perhaps some other
kind of modification of sounds in the 6 Hz range can be reliably
perceived.

Not in the literature that I can find.

Your inability to find relelvant literature that doesn't fit your agenda is
well-known Atkinson. I'll make it easy for you - screw the literatre and
listen for yourself::

http://www.pcabx.com/technical/high_pass/index.htm

In addition, there seems to be
agreement that perception of very low frequencies (though higher than
6Hz) involves the body rather than the ears.

Absence of cites of relevant sources noted. This is just more of the
proof-by-assertion, speculation, and greviously-flawed listening evaluation
that we've had to bear with this author as long as he has been writing about
audio.

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.

Was this a double-blind test involving a high-pass filter?

Yes.

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 reasonbly precise implmentation of
the type of filter it is stated to be. My web site posts results are based
on Audition's butterworth high-pass filters. At
http://www.pcabx.com/technical/high_pass/index.htm I present audio samples
developed with no additional filtering, as well as sixth order and third
order butterworth filters.

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.