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

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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 09:39:00 +0000 (GMT), Jim Lesurf
wrote:

In article , Java Jive
wrote:

After some searching I've just found some AC recordings of tracks from
an album that I now have on CD, it's Barbara Dickson's seminal folk
album "From The Beggar's Banquet", 1970. The AC recordings were
originally made from a library copy of the LP, while the CD is a
re-issue of 5 or 6 years ago that I feel most fortunate to have
obtained. The difference between the two is utterly unmistakable.

Alas the LP and CD come into that if you're trying to assess AC.
Particularly if you've not heard the LP for a long time and become
habituated to the AC.

Of course, but equally, I have several digitisations of vinyls of
similar material and sound, digitised on the same deck with the same
cartridge, and they too are way better than these AC recordings. Also,
I have both a commercial AC and a rather worn vinyl of Eddie Walker's
"Red Shoes On My Feet", and, even though worn with a great deal of
needle-in-the-groove noise, the vinyl is otherwise still way better
quality than the AC. From this and many other historical AC
recordings now replaced from better sources, I know that the big
problem with AC is the slow tape-speed, leading to the poor FR, and
the narrowness of the tape which contributes to a generally poor SNR.

FWIW I also routinely find that an LP sounds different to a CD of the
'same' material. The problem being that this may be down to the two
versions being 'mastered' sic quite differently. Can tell you more about
the people cutting the LP or 'improving' sic again what they put on LP
than it does about the frequency response capabilities of either system.

Yes, yes, we've been here several times before, and generally tend to
agree on the topic.

All comes down to how much care and skill were applied when producing the
LP or CD, and to the replay systems.

As I said at the top of this sub-thread, but care can not make up for
the low FR of AC, a constraint arising out of its slow tape-speed.
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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

On 08/03/2015 11:34, Sumatriptan wrote:

it's a pigs ear.


Just for closure on the hum issue...

I corrected the wiring errors causing the L-R reversal and phasing
error. I also fitted the Behringer phono--USB into the turntable as per
suggestions in this thread. The (good quality) screened cables from
tonearm wire connectors to the Behringer phono inputs are now about 3 cm
long. Hum is now completely gone. At maximum volume with tt motor
running the only sound is a small amount of noise, presumably from the
preamp front end.

In article ,
Java Jive wrote:
As I said at the top of this sub-thread, but care can not make up for
the low FR of AC, a constraint arising out of its slow tape-speed.

Commercial cassettes were usually duplicated at high speed. So never going
to be at the top end of even that lowly format.

Cassettes made on a good home deck using top quality tape could be
remarkably good, considering.

--
*Ever stop to think and forget to start again?

Dave Plowman London SW
To e-mail, change noise into sound.