On 09/03/2015 20:49, Trevor Wilson wrote:


MORAL: With sufficient intensity, human hearing can extend way past
20kHz.


I wouldn't exactly call the sensation of a high level 20 kHz tone
'hearing' more like 'detection'. My normal hearing barely extends to
9-10 kHz these days but I was aware of an odd clicking sensation (best
way I can describe it) in an a relatives garden. Turned out to be a cat
repellent gadget. Sensation vanished when it was switched off.

I've also been aware of a vaguely uncomfortable feeling standing close
to a shop window that had some sort of 'anti-teen' sound device
installed. Couldn't hear anything at all...just an awareness of
something unpleasant. And I'm no teen.

In article , Sumatriptan
wrote:
On 09/03/2015 20:49, Trevor Wilson wrote:


MORAL: With sufficient intensity, human hearing can extend way past
20kHz.


I wouldn't exactly call the sensation of a high level 20 kHz tone
'hearing' more like 'detection'. My normal hearing barely extends to
9-10 kHz these days but I was aware of an odd clicking sensation (best
way I can describe it) in an a relatives garden. Turned out to be a cat
repellent gadget. Sensation vanished when it was switched off.

I've also been aware of a vaguely uncomfortable feeling standing close
to a shop window that had some sort of 'anti-teen' sound device
installed. Couldn't hear anything at all...just an awareness of
something unpleasant. And I'm no teen.


FWIW Oohashi and others published research papers some years ago which
reported doing things like brain scans whilst people listened to sound
with/without and 'ultrasonic' portion.

Played by itself, people couldn't hear the 'ultrasound'. But their
brainscans were different with/without it when the main music was played.

So it seems possible that high frequency tones which are - in isolation -
'inaudible' may affect our perception when they accompany clearly audible
lower frequency sounds.

This isn't particularly surprising if true since human hearing physiology
is known to be highly nonlinear.

What it means for listening to music is harder to say. But it does make it
plausible that there *might* be some advantage in having bandwidths above
20kHz even when you can't hear isolated tones at that frequency, at least
in some cases.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Tue, 10 Mar 2015 13:15:43 +0000 (GMT), Jim Lesurf
wrote:

In article , Sumatriptan
wrote:
On 09/03/2015 20:49, Trevor Wilson wrote:


MORAL: With sufficient intensity, human hearing can extend way past
20kHz.


I wouldn't exactly call the sensation of a high level 20 kHz tone
'hearing' more like 'detection'. My normal hearing barely extends to
9-10 kHz these days but I was aware of an odd clicking sensation (best
way I can describe it) in an a relatives garden. Turned out to be a cat
repellent gadget. Sensation vanished when it was switched off.

I've also been aware of a vaguely uncomfortable feeling standing close
to a shop window that had some sort of 'anti-teen' sound device
installed. Couldn't hear anything at all...just an awareness of
something unpleasant. And I'm no teen.


FWIW Oohashi and others published research papers some years ago which
reported doing things like brain scans whilst people listened to sound
with/without and 'ultrasonic' portion.

Played by itself, people couldn't hear the 'ultrasound'. But their
brainscans were different with/without it when the main music was played.

So it seems possible that high frequency tones which are - in isolation -
'inaudible' may affect our perception when they accompany clearly audible
lower frequency sounds.

This isn't particularly surprising if true since human hearing physiology
is known to be highly nonlinear.

What it means for listening to music is harder to say. But it does make it
plausible that there *might* be some advantage in having bandwidths above
20kHz even when you can't hear isolated tones at that frequency, at least
in some cases.

Jim

I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.

d

In article , Don Pearce
wrote:

Played by itself, people couldn't hear the 'ultrasound'. But their
brainscans were different with/without it when the main music was
played.

So it seems possible that high frequency tones which are - in isolation
- 'inaudible' may affect our perception when they accompany clearly
audible lower frequency sounds.


I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.

Agreed. Which in turn implies that the sound *level* may matter. i.e. Any
such impact on the 'perceived sound quality' may only occur when the sound
level at the ears is loud enough. Which may indicate why some people notice
and care whilst others don't - even if using the same kit and having
'similar ears' in conventional hearing tests.

But to me this all illustrates the problem I found so regrettable wrt many
claims of 'cable sound'. Since none of those making the claim would take
the test, we couldn't find out if/when they were right or mistaken. No way
to sort wheat from chaff.

I'd have been facinated to get assessable evidence for the possibility of
some genuine new factor here. Partly to learn something new and
interesting. Partly to then be able to systematically engineer better audio
systems *without* having to suffer the many 'enthusiastic' claims made by
manufacturers for their very, very expensive cables - when something
cheaper and easier might do just fine without all the promotional blarny or
product cost.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 10/03/2015 15:10, Jim Lesurf wrote:
In article , Don Pearce
wrote:

Played by itself, people couldn't hear the 'ultrasound'. But their
brainscans were different with/without it when the main music was
played.

So it seems possible that high frequency tones which are - in isolation
- 'inaudible' may affect our perception when they accompany clearly
audible lower frequency sounds.


I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.

Agreed. Which in turn implies that the sound *level* may matter. i.e. Any
such impact on the 'perceived sound quality' may only occur when the sound
level at the ears is loud enough. Which may indicate why some people notice
and care whilst others don't - even if using the same kit and having
'similar ears' in conventional hearing tests.


These threads feel like some kind of altered reality. Sound is
experienced in all manner of ways - not just through ears.

Honestly, you boffins. Surprised we get anything done with you lot
pushing the buttons :-)

--
Cheers, Rob

On 10/03/2015 14:38, Don Pearce wrote:

I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.


There's a simple test that could confirm that idea.

Two (or more) high level ultrasonic tones a few hundred Hz apart should
result in audible tones. Surely this has been tried.

I know that this sort of two-tone intermod test is used in audio systems:

http://www.whathifi.com/forum/comput...ms-performance

There is a download file for this test at the above location.

For testing human ear linearity, the levels would have to be high and
the tones generated separately in independent systems to eliminate audio
system intermod from the test results. I would think the required
equipment would be available in many audiophile premises. Any takers? ;-)

On Tue, 10 Mar 2015 18:29:28 +0000, Sumatriptan
wrote:

On 10/03/2015 14:38, Don Pearce wrote:

I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.


There's a simple test that could confirm that idea.

Two (or more) high level ultrasonic tones a few hundred Hz apart should
result in audible tones. Surely this has been tried.

I know that this sort of two-tone intermod test is used in audio systems:

http://www.whathifi.com/forum/comput...ms-performance

There is a download file for this test at the above location.

For testing human ear linearity, the levels would have to be high and
the tones generated separately in independent systems to eliminate audio
system intermod from the test results. I would think the required
equipment would be available in many audiophile premises. Any takers? ;-)


I'm pretty sure my speakers can't do anything much with 30 and 33kHz.
I'll try with 20 and 23.

d

On Tue, 10 Mar 2015 18:29:28 +0000, Sumatriptan
wrote:

On 10/03/2015 14:38, Don Pearce wrote:

I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.


There's a simple test that could confirm that idea.

Two (or more) high level ultrasonic tones a few hundred Hz apart should
result in audible tones. Surely this has been tried.

I know that this sort of two-tone intermod test is used in audio systems:

http://www.whathifi.com/forum/comput...ms-performance

There is a download file for this test at the above location.

For testing human ear linearity, the levels would have to be high and
the tones generated separately in independent systems to eliminate audio
system intermod from the test results. I would think the required
equipment would be available in many audiophile premises. Any takers? ;-)


Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ
- not much help.

I made a file with 20kHz and 38kHz. The 2kHz product was clearly
audible, and very level dependent. There was actually some kind of
threshold effect. I prevented distortion in the amplifier being a
confounding factor by recording them on separate channels.

d

On Tue, 10 Mar 2015 18:51:46 GMT, (Don Pearce) wrote:

On Tue, 10 Mar 2015 18:29:28 +0000, Sumatriptan
wrote:

On 10/03/2015 14:38, Don Pearce wrote:

I think a likely explanation is the simple non-linearity of the ear
causing audible intermod products when the ultrasonics were on.


There's a simple test that could confirm that idea.

Two (or more) high level ultrasonic tones a few hundred Hz apart should
result in audible tones. Surely this has been tried.

I know that this sort of two-tone intermod test is used in audio systems:

http://www.whathifi.com/forum/comput...ms-performance

There is a download file for this test at the above location.

For testing human ear linearity, the levels would have to be high and
the tones generated separately in independent systems to eliminate audio
system intermod from the test results. I would think the required
equipment would be available in many audiophile premises. Any takers? ;-)


Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ
- not much help.

I made a file with 20kHz and 38kHz. The 2kHz product was clearly
audible, and very level dependent. There was actually some kind of
threshold effect. I prevented distortion in the amplifier being a
confounding factor by recording them on separate channels.

d

And attempting to move it all down as far as possible to make life
easier on the tweeters, I find I can still hear 16kHz! I thought those
days were long gone - one happy bunny here.

d

In article , Don Pearce
wrote:
Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ -
not much help.

Why are you assuming their'd be no f1 - f2 result?

I made a file with 20kHz and 38kHz. The 2kHz product was clearly
audible, and very level dependent. There was actually some kind of
threshold effect. I prevented distortion in the amplifier being a
confounding factor by recording them on separate channels.

2*f1 - f2 ?

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html