"Dave Plowman (News)" wrote in message
...
In article ,
Trevor Wilson wrote:
surely you mean "a good analogue recording transcribed to vinyl"? I
mentioned before that I was under the impression that vinyl cutters
have trouble etching high frequencies onto the vinyl.

**Then you'd be wrong. There is no reason why *any* waveform cannot be
coaxed onto a vinyl disk.

This depends very much at the level you attempt to record it at.

It is just a matter of how much trouble one is willing to go to. Don't
forget: A square wave, on a vinyl recording (physically) looks like a
triangle wave. BTW: I have a CBS test disk with square waves recorded
on it. They appear on a 'scope with far higher fidelity (provided I use
a high quality turntable) than any 16/44 digital system.

I'll bet much of that square wave consists of distortion added at
playback.

**I doubt it.


Be interesting to see the actual cut on the record via a microscope.

**It looks like a triangle wave. I've put it under a high(ish) lower
microscope. It is also stated as much on the liner notes.


--
Trevor Wilson
www.rageaudio.com.au

On Fri, 12 Nov 2004 21:11:20 GMT, "Trevor Wilson"
wrote:


"Tat Chan" wrote in message
...

"Trevor Wilson" wrote in message



**16/44 digital can't even reproduce a decent 5kHz square wave.

Well, it would have the fundamental and third harmonic so the resulting
wave would have plenty of ripple.

**I'll give you a hint: It looks nothing like a square wave.

It does however look more like a square wave, than does a 5kHz square
wave from vinyl.......................

surely you mean "a good analogue recording transcribed to vinyl"?
I mentioned before that I was under the impression that vinyl cutters have
trouble etching high frequencies onto the vinyl.

**Then you'd be wrong. There is no reason why *any* waveform cannot be
coaxed onto a vinyl disk. It is just a matter of how much trouble one is
willing to go to. Don't forget: A square wave, on a vinyl recording
(physically) looks like a triangle wave. BTW: I have a CBS test disk with
square waves recorded on it. They appear on a 'scope with far higher
fidelity (provided I use a high quality turntable) than any 16/44 digital
system.

I believe that would be either (a) a lie or (b) an artifact of the
cart ringing. BTW, after RIAA boosting, basically a differentiation of
the inout square wave, the groove does *not* look like a triangle
wave.

The mighty Dynavector 10D-II can operate to 60kHz.
The square wave
performance of this very fine cartridge is exemplary.

that is the performance of the cartridge, not the LP

**It is the thereorectical performance of the SYSTEM. Rarely, if ever,
achieved in practice.

That's because most vinyl craps out below 20kHz......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article , Arny Krueger wrote:
"Keith G" wrote in message

"Tat Chan" wrote

I was under the impression that the LP disc cutters had problems
placing high frequencies ( 20kHz???) onto the LP.

Where did that impression come from??

The study of science. While the CD format can handle FS @ 20 KHz with
aplomb, 20 KHz can't possibly be recorded on vinyl at anything like peak
levels.

I am not familiar with what FS (or peak level) might mean at 20 kHz for a
vinyl disc. However, I think only a few normal musical instruments have
fundamentals exceeding 2 kHz (possibly harp, violin, flute and piccolo).

The higher harmonics I have seen in spectrum plots are much smaller in
amplitude than the fundamentals so I guess high level recording capability
may not be needed at 20 kHz.

--
John Phillips

In article ,
John Phillips wrote:
I am not familiar with what FS (or peak level) might mean at 20 kHz for
a vinyl disc. However, I think only a few normal musical instruments
have fundamentals exceeding 2 kHz (possibly harp, violin, flute and
piccolo).

The higher harmonics I have seen in spectrum plots are much smaller in
amplitude than the fundamentals so I guess high level recording
capability may not be needed at 20 kHz.

Which is how the RIAA characteristic came about. Had there been real
energy at HF in most music, it wouldn't have worked.

--
*Procrastinate now

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

"Dave Plowman (News)" wrote in message

In article ,
John Phillips wrote:
I am not familiar with what FS (or peak level) might mean at 20 kHz
for a vinyl disc. However, I think only a few normal musical
instruments have fundamentals exceeding 2 kHz (possibly harp,
violin, flute and piccolo).

The higher harmonics I have seen in spectrum plots are much smaller
in amplitude than the fundamentals so I guess high level recording
capability may not be needed at 20 kHz.

Which is how the RIAA characteristic came about. Had there been real
energy at HF in most music, it wouldn't have worked.

It took a while, but recording engineers and producers eventually realized
that since digital became mainstream, they weren't limited by the media,
when it comes to the amplitude and spectral content of recordings.

We now commonly have recordings that peak at FS for extended periods of
time, and also have flat power spectral densities. Of course, they sound
loud and bright, but that's apparently what some people like.

The market is now full of digital recordings that could never be played as
LPs without very audible remastering.

John Phillips wrote:

I think only a few normal musical instruments have
fundamentals exceeding 2 kHz (possibly harp, violin, flute and piccolo).

A piano goes up to 4.

In article , Eiron wrote:
John Phillips wrote:

I think only a few normal musical instruments have
fundamentals exceeding 2 kHz (possibly harp, violin, flute and piccolo).

A piano goes up to 4.

Yes - I was even listening to a recording of one when I wrote that so
the omission is inexplicable. I also understand some organ pipes get
well into the next octave (used for timbre purposes I believe rather
than at high level).

On a related matter there is a book on the psychology of music that is
reported to claim human perception of the character of a note takes in
only the harmonics up to 7th.

"Our ears can only discern up to seven harmonics, though. By this
I mean that if I were to remove the harmonics of a tone, which
theoretically can go to infinity, I could get down to the seventh
one before you would start noticing a change in the sound of the tone."

But that, as commonly understood, the relationships remain important.

"Also, if I start to change the amplitude, or loudness, of the
harmonics, you would begin to notice this very easily (The Psychology
of Music - Diana Deutsch)."

Interestingly 20 kHz/7 or about 2,850 Hz seems to be the point above
which those relatively few musical instruments produce fundamentals.

--
John Phillips

In article ,
Arny Krueger wrote:
The market is now full of digital recordings that could never be played
as LPs without very audible remastering.

Nothing really new there then - despite what some would have you believe.
;-)

Very few analogue master tapes ever went 'straight' to vinyl either.

--
*I almost had a psychic girlfriend but she left me before we met *

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

In article , Arny Krueger
wrote:
"Don Pearce" wrote in message

On Fri, 12 Nov 2004 15:14:33 +0000 (GMT), Jim Lesurf
wrote:


At what level, and at what distortion? I'd also wonder what the cut
squarewave might look like after a few dozen playings...

Worth remembering that a square wave recorded on vinyl will be - in
physical groove terms - a triangular wave, which may not be too bad
from a tracking point of view.

Since the playback device is veolcity sensitive, a triangle shaped
groove would produce a square wave output from the cartridge seems
intuitively clear. However, the idea that the groove is a triangle
presumes no RIAA pre-emphasis. The RIAA playback curve can be
approximated by an integrator. Therfore, the groove shape has to be
something like a differentiated triangle, no?


Must admit my first reaction was 'triangle', but then I remembered
RIAA and the velocity modulation...

IIUC the high time-constant of RIAA is 75 microseconds. That comes
out as a turnover of 2.122 kHz.

So, for a 5kHz squarewave, the signal will approximately be
differentiated by the RIAA, but then this signal produces the
desired cutter velocity. Since the displacement is the integral
(in time) of the velocity the cut displacement pattern is
then the integral of this differential. So my guess is we
end up with what looks like a square-wave shape cut on the groove
walls. (Nominally.)

How close it would look would depend upon the cutter shape, drive
to the cutter, etc. Then be modified again by the stylus shape
when replayed...

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Arny Krueger
wrote:


**Then you'd be wrong. There is no reason why *any* waveform cannot be
coaxed onto a vinyl disk.

Sure there is: the problem of tracking it, once cut. Cartridges have
styli with finite radii.

I also wonder about the need for burnishing facets on the cutter, and it
having an angled back face. Also, flow/deformation of the material being
cut. No idea how high you could push the response provided you were willing
to wind down the amplitude, though.

I'm also ignoring the requirements to actually drive the cutter
modulation...

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html