Just to let people know I've just added some new material to the
'audiomisc' site. :-)

A) Page on Radford and Bailey, and their power amps. This is based on a HFN
article from last year, but I have extended the article. I've also tied it
in to circuit diagrams of some of the relevant designs. (The diagrams were
already on the site, but until now there were no links to them, so you had
to know where they were!)

B) First of the series of HFN articles on LP performance. This deals with
the maximum signal levels that can be recorded/replayed.

Will shortly add another page where I show results of measurements of the
peak levels found on various LPs.

Slainte,

Jim

--
Change 'noise' to 'jcgl' 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 Thu, 22 May 2008 16:50:38 +0100, Jim Lesurf
wrote:

Just to let people know I've just added some new material to the
'audiomisc' site. :-)

A) Page on Radford and Bailey, and their power amps. This is based on a HFN
article from last year, but I have extended the article. I've also tied it
in to circuit diagrams of some of the relevant designs. (The diagrams were
already on the site, but until now there were no links to them, so you had
to know where they were!)

B) First of the series of HFN articles on LP performance. This deals with
the maximum signal levels that can be recorded/replayed.

Will shortly add another page where I show results of measurements of the
peak levels found on various LPs.

Slainte,

Jim

JIm, there is another point you might want to consider, which is that
Shannon's limit applies only to data transmitted over the defined
path. But music in particular is not like that. When we listen to
familiar music it is already stored in our brain and all that is
necessary to trigger it is a very small correlation from the signal;
it is a little like CDMA from this point of view - a clean signal can
be recovered from an apparently impossible signal to noise ratio
because the spreading code is known at both ends of the link, and
doesn't not actually get transmitted and received.

So a familiar tune sunk well into the noise will be heard, while
random notes may be missed.

I know this is not what your article is about, but I think it is
relevant and you never know, may be worth a research grant to quantify
the effect.

d

--
Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message


JIm, there is another point you might want to consider,
which is that Shannon's limit applies only to data
transmitted over the defined path. But music in
particular is not like that. When we listen to familiar
music it is already stored in our brain and all that is
necessary to trigger it is a very small correlation from
the signal; it is a little like CDMA from this point of
view - a clean signal can be recovered from an apparently
impossible signal to noise ratio because the spreading
code is known at both ends of the link, and doesn't not
actually get transmitted and received.

IOW, the amount of data transmitted over the given data link at that time is
far less than the amount of correct data that is present at the receiver,
because the receiver has other transmissions in its memory that it uses to
develop the correct data that is perceived at that time.

So a familiar tune sunk well into the noise will be
heard, while random notes may be missed.

....depending on the reliability of the data that has been stored in memory
and the quality of the new data.

I know this is not what your article is about, but I
think it is relevant and you never know, may be worth a
research grant to quantify the effect.

This is a way to explain how people can hear what they say they hear when
they listen to vinyl. ;-)

On Thu, 22 May 2008 15:23:48 -0400, "Arny Krueger"
wrote:

"Don Pearce" wrote in message


JIm, there is another point you might want to consider,
which is that Shannon's limit applies only to data
transmitted over the defined path. But music in
particular is not like that. When we listen to familiar
music it is already stored in our brain and all that is
necessary to trigger it is a very small correlation from
the signal; it is a little like CDMA from this point of
view - a clean signal can be recovered from an apparently
impossible signal to noise ratio because the spreading
code is known at both ends of the link, and doesn't not
actually get transmitted and received.

IOW, the amount of data transmitted over the given data link at that time is
far less than the amount of correct data that is present at the receiver,
because the receiver has other transmissions in its memory that it uses to
develop the correct data that is perceived at that time.


Exactly.

So a familiar tune sunk well into the noise will be
heard, while random notes may be missed.

...depending on the reliability of the data that has been stored in memory
and the quality of the new data.


Yup, you may lose it if it is a version you haven't heard before.

I know this is not what your article is about, but I
think it is relevant and you never know, may be worth a
research grant to quantify the effect.

This is a way to explain how people can hear what they say they hear when
they listen to vinyl. ;-)


Pretty much...

d

--
Pearce Consulting
http://www.pearce.uk.com

In article , Don Pearce
wrote:
On Thu, 22 May 2008 16:50:38 +0100, Jim Lesurf
wrote:

Just to let people know I've just added some new material to the
'audiomisc' site. :-)


JIm, there is another point you might want to consider, which is that
Shannon's limit applies only to data transmitted over the defined path.
But music in particular is not like that. When we listen to familiar
music it is already stored in our brain and all that is necessary to
trigger it is a very small correlation from the signal; it is a little
like CDMA from this point of view - a clean signal can be recovered from
an apparently impossible signal to noise ratio because the spreading
code is known at both ends of the link, and doesn't not actually get
transmitted and received.

So a familiar tune sunk well into the noise will be heard, while random
notes may be missed.

The above is an interesting point. I may well steal it for a future
article. :-) I do intend (soon) to do the planned article on comparing
the channel information bandwidths of various systems, including ideal LP.
Your point could certainly be added - but of course it applies to any of
the systems, so does not give a specific advantage to any. Although it may
mitigate against the 'poorest' in Shannon terms seeming as 'poor' in terms
of the impression when listening to familiar music.

I know this is not what your article is about, but I think it is
relevant and you never know, may be worth a research grant to quantify
the effect.

Afraid I am long past the days of caring about 'research grants'. I just
toddle along doing what I find interesting and can cobble together. ;-

Slainte,

Jim

--
Change 'noise' to 'jcgl' 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

I have now added two more pages to the audiomisc site.

The main new page is the web version of the HFN article showing statistics
for the measured peak velocities, etc, I found on various LPs. However I
didn't have space in the magazine for all the results I obtained. So I have
also provided a 'gallery' page showing the results omitted from the printed
article. :-)

The results seems interesting for various reasons. Most obvious being that
- notably with rock/pop LPs - the vertical (stereo difference) modulation
levels are generally much lower than the horizontal (mono) ones. Not sure
if this is due to the artificial 'pan pot stereo' layouts, or due to
deliberate modification to avoid larger vertical modulations on the LP. But
as with modern CD, some pop/rock LPs also show signs of level compression.

A later article looked at reasons why the peak accelerations are somewhat
less than the simple engineering of the previous article indicated. That
will appear on the website in due course...

Slainte,

Jim

--
Change 'noise' to 'jcgl' 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

"Arny Krueger" wrote in message
. ..
"Don Pearce" wrote in message


JIm, there is another point you might want to consider,
which is that Shannon's limit applies only to data
transmitted over the defined path. But music in
particular is not like that. When we listen to familiar
music it is already stored in our brain and all that is
necessary to trigger it is a very small correlation from
the signal; it is a little like CDMA from this point of
view - a clean signal can be recovered from an apparently
impossible signal to noise ratio because the spreading
code is known at both ends of the link, and doesn't not
actually get transmitted and received.

IOW, the amount of data transmitted over the given data link at that time
is far less than the amount of correct data that is present at the
receiver, because the receiver has other transmissions in its memory that
it uses to develop the correct data that is perceived at that time.

So a familiar tune sunk well into the noise will be
heard, while random notes may be missed.

...depending on the reliability of the data that has been stored in memory
and the quality of the new data.

I know this is not what your article is about, but I
think it is relevant and you never know, may be worth a
research grant to quantify the effect.

This is something very familiar, and taught to most
music and recorded arts students.

Your point is the reason why many still prefer the
classical interpretations of Toscanini or Klemperer, and
why the now familiar style of Sir Simon Rattle and the Berlin
Symphony Orchestra, (what a perfect combination:-)
or Christopher Hogwood and the AAM are so much
to people's (acquired) taste.

So, for instance the Rattle/Berlin Symphony recording
of Mahler VI has become something of a reference -
the one with which many of us are familiar - and by which
other versions are judged.

One becomes accustomed to the style of an artist, a
conductor and orchestra, whose performances are
clearly identifiable, as if stamped with a signature.
The same goes for preferences in record labels -
people look for say a Decca or DGG version
- and even one recorded in a particular location.
It is something to which they can relate.

By the same token, the classical producer and engineer
team use the inner reference of a similar work recorded
by the same orchestra in the same location to achieve the
balance of the current project. Sometimes, they will take
previously recorded material with them for comparison.
Once again the recording has that team's signature.

Comparing classical recordings is fairly simple, as all are
played from the composers score, so the variables are
largely due to the standard of the performance, the
personal interpretation of the work by conductor and
soloists,and the way it has been recorded.

I found it fascinating to compare the recordings
of the works of Sibelius. Quite often the tempi
and interpretations of versions conducted by the
great man himself, did not seem as "appropriate"
as those versions conducted by Berglund or
Segerstam.

In pop music, such comparisons are more difficult.
There are few cover versions made of hits, except
of "evergreens" by artists such as James Taylor,
Carole King etc. (everyone wants to have a go
at those!) And the record companies that
used to specialise in cover versions (Embassy
in the UK for example) have long since vanished.

Also in jazz, comparisons between versions are difficult to
make. Most "covers" are made as tributes, and usually only
loosely based on the theme of the original work.Duke
Ellington, Benny Goodman, Count Basie, and
Charlie Parker among others, fall into this category.
Jazz, by virtue of improvisation makes it difficult to
compare two versions of the same work, even by
the same artist. Recent comparison of "alternative takes"
with the well-known versions of Ellington's Newport Jazz
Festival recordings seem odd, at least to me, at first.
The published versions are so familiar, and the solos
fit the reference exactly. Alternative versions have
to be regarded as separate works, as they can be
so different.

This is a way to explain how people can hear what they say they hear when
they listen to vinyl. ;-)

I think it has more to do with comparing a good vinyl
cut/pressing (which is theoretically the inferior medium)
with a CD that has undergone considerable, and usually
unnecessary processing during the mastering process..
People gain the impression based upon what they hear,
that the LP is a superior medium.

The recent Ray Charles/Count Basie release is a perfect example.

It is also interesting to compare vinyl and CDs made in the early
1980s. Many CD's have been reissued, "enhanced" and digitally
remastered again and again since that time. Sometimes they have
bonus tracks previously unavailable on CD to assist with sales.
With each successive version the crest factor is eroded away,
to the considerable detriment of the performance.

Regards
Iain