Reply
 
Thread Tools Display Modes
  #161   Report Post  
Ian Iveson
 
Posts: n/a
Default

"Phil Allison" wrote

A periodic discontinuity requires an infinite number of terms
to resolve.


** No real world one does - since it is band limited.


The real world is continuous. There are no band limited
discontinuities.

As you were told earlier in the thread.


A periodic discontinuity requires an infinite number of terms to
resolve. True

A simple fact that counters the insane rubbish you are preaching.


No, I said "A periodic discontinuity requires an infinite number of
terms to resolve.", which is true.

cheers, Ian


  #162   Report Post  
Phil Allison
 
Posts: n/a
Default


"Ian Iveson"
"Phil Allison

A periodic discontinuity requires an infinite number of terms to
resolve.


** No real world one does - since it is band limited.


The real world is continuous. There are no band limited discontinuities.



** Cos there are no true discontinuities in the real world at all.

They are a mathematical abstraction.



A simple fact that counters the insane rubbish you are preaching.


No, I said "A periodic discontinuity requires an infinite number of terms
to resolve.", which is true.



** A simple, mathematical discontinuity has ** infinite** bandwidth.

However, real world discontinuities have limited bandwidth and hence a non
infinite series expansion - so they CAN be exactly represented by a
series of sine waves.


BTW

Allison's Theorem says:

" Iveson is an ass. "

Iveson himself keeps proving the rightness of this theorem.




............. Phil



  #163   Report Post  
Ian Iveson
 
Posts: n/a
Default

"Phil Allison" wrote

** How bizarre - cold air would do.


Obviously not. Helium is lighter.

cheers, Ian


  #164   Report Post  
Ian Iveson
 
Posts: n/a
Default

"Joseph Meditz" wrote

"No, an impulse is not composed of waves, and has no Fourier
transform."


YIKES!


Have you got a point to make?

"You may contrive an approximation, perhaps using a delta
function,
but a simple impulse is a singularity, has no period, and
therefore
no transform."
YIKES!


Have you got a point to make?

http://mathworld.wolfram.com/Fourier...aFunction.html


You looked it up. Well done!

Have you got a point of your own to make, or are you just confirming
mine?

Once again, I say that you need to study the Fourier Transform.


I could give you a long list of things you might study, including
the difference between the transient and frequency domains, and
between transient and steady-state response, and between a simple
impulse and a delta function, and between a simple ramp and an
integral of the delta function, and between a step and a null. Since
you think you already know everything, I shan't bother.

cheers, Ian



  #165   Report Post  
Ian Iveson
 
Posts: n/a
Default

"Phil Allison" wrote

However, real world discontinuities have limited bandwidth and
hence a non
infinite series expansion - so they CAN be exactly
represented by a
series of sine waves.


Only if they are periodic.

Nothing in the real world is periodic. Specifically, nothing in
music is precisely periodic. If you look you will see that it is the
assumption of periodicity that most concerned me.

Your daft notion of instantaneous frequency won't impress, so don't
bother embarrassing yourself again. Unless of course you know how to
detect frequency with one instantaneous sample.

cheers, Ian




  #166   Report Post  
Phil Allison
 
Posts: n/a
Default


"Ian Iveson"
"Phil Allison"
However, real world discontinuities have limited bandwidth and hence a
non infinite series expansion - so they CAN be exactly represented
by a series of sine waves.


Only if they are periodic.



** This featherless parrot keeps repeating its insane mantra.


Nothing in the real world is periodic.



** We have a full on pommy fruit cake here - boys and gals.


Specifically, nothing in music is precisely periodic.



** Yawn.....


If you look you will see that it is the assumption of periodicity that
most concerned me.



** Ida Iveson must be having one of her "periods".



Your daft notion of instantaneous frequency won't impress,



** Not my notion and you need to post under the relevant words - you
demented pommy arsehole.




.............. Phil


  #167   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Phil Allison" wrote in message
...

"Iain M Churches"

There are countless LP's, for example the Oscar Peterson trio recording
I am listening to at the moment, with piano across the centre, bass on
one side and drums on the other.



** A fool argues using irrelevant examples.




............... Phil

Hello Phil,

I have just taken a look at this track on a spectral analyser, and with the
exception of a small amount of studio leakage, there is no string bass on
the opposite track. There would be if the LF was centred. Listening to
just the other track in mono confirms this. This recording dates from
the 60's, and was probably made on a three track Ampex 350 series
tape machine, hence the interesting configuration. This is by no
means a unique example.

You are correct in your statement that LF can be routed centre. At Decca
we called is LF phase, with a switch marked as such on the console.
I studied cutting for a period of two years, under senior engineer Harry
Fisher
as a part of my training. LF phase was used only when it was
absolutely necessary. As you so rightly pointed out the vertical modulation
afforded to the cutting head is severely limited, by the thickness of the
lacquer layer on the disc. In fact, American lacquers (Westrex) were
considerably thinner than those we used in Europe

You make no further mention of helium cooling, so presumably you have
checked the facts, and found my statement to be correct, just as Stewart
did.

I should be interested to hear of your disc cutting experience.

Iain

Oh, and Phil.....Please try to be civil. Your insults and expletives do
nothing to strengthen the content of your posts. In fact quite the reverse.
I am happy to discuss disc cutting with you, but if you are unable to do so
in a civilised manner I shall reach the conclusion that you are either
socially
challenged or in need of professional help, and consign your posts to
a killfile, as so many others on RAT have done.



  #168   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...

(huge snip)
Don't take what Churches says about vinyl too seriously, his
experience is some twenty years out of date.
--


Disc cutting was a mature technology by the time I was cutting
in the late 60's early 70's. Decca had eight cutting rooms, so
quite an important facility, second only in size to Abbey Road.
The equipment was state of the art, Neumann, and Westrex
lathes, with Neumann, Lyrec and Decca cutting heads and
amplifiers. There have been no significant improvements
in technique since that time. I was taught by Harry
Fisher, the senior classical cutting engineer at Decca, so the
instruction was probably the finest one could receive in the
UK.

In those two years, I must have cut several hundred sides of
master lacquer, using my own ID letter.

I would be interested to hear the details of your cutting expertise.

Cordially,

iain





  #169   Report Post  
Phil Allison
 
Posts: n/a
Default


"Iain M Churches"
"Phil Allison"

There are countless LP's, for example the Oscar Peterson trio recording
I am listening to at the moment, with piano across the centre, bass on
one side and drums on the other.


** A fool argues using irrelevant examples.


I have just taken a look at this track on a spectral analyser, and with
the
exception of a small amount of studio leakage, there is no string bass on
the opposite track.



** A fool argues using irrelevant examples # 2



There would be if the LF was centred. Listening to
just the other track in mono confirms this. This recording dates from
the 60's, and was probably made on a three track Ampex 350 series
tape machine, hence the interesting configuration. This is by no
means a unique example.



** A fool argues using irrelevant examples # 3

An even bigger bloody fool argues from the particular to the general.



You are correct in your statement that LF can be routed centre.



** Usenet etiquette and common sense requires one to post under the
other's words - what makes you think you do not have to
????????????????????????????????????????????

Your obvious autism is not an excuse.


At Decca
we called is LF phase, with a switch marked as such on the console.
I studied cutting for a period of two years, under senior engineer Harry
Fisher as a part of my training. LF phase was used only when it was
absolutely necessary.



** As it would be *whenever* there was strong LF content in one channel.


As you so rightly pointed out the vertical modulation
afforded to the cutting head is severely limited, by the thickness of the
lacquer layer on the disc.



** Wrong again - go draw a V shaped groove profile and figure out how
upwards motion is created.

See how small the potential excursion is ????


You make no further mention of helium cooling,



** High time for you to explain what seems a joke to most.



Oh, and Phil.....Please try to be civil.




** Go and get utterly ****ed - you posturing, pommy arsehole.

You are one stupid, arrogant, irrational bloody public menace.

No wonder you actually admire excreta like the Turneroid.



Your insults and expletives do
nothing to strengthen the content of your posts.



** The idea is to get ****ing useless imbeciles like you OFF usenet
altogether !

All you and your putrid ilk do is stand square in the way of any real info
ever being exchanged.

**** off !!!!!!



............... Phil


  #170   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 12:40:12 +1100, "Phil Allison"
wrote:

"Iain M Churches"

"Phil Allison"

** The cutter head may need cooling - but Helium is not a good coolant.

The cutting stylus is in fact *heated* .


The cutting stylus is indeed heated. The cutter head coil is cooled
as required with helium. This is a fact which is well documented.


** How bizarre - cold air would do.


Helium has much higher heat capacity than air, and much lower mass. It
is an excellent (and inert) cooling medium, and is used in many
industrial processes.
--

Stewart Pinkerton | Music is Art - Audio is Engineering


  #171   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Sun, 13 Mar 2005 20:44:59 +0200, "Iain M Churches"
wrote:

"Stewart Pinkerton" wrote in message
.. .

He still thinks that LF is panned centre and rolled off at 80Hz.


As indeed it is, of necessity which Churches *should* understand, but
apparently does not. You can lead a whore tae culture, but ye canna
make her think............................


There are countless LP's, for example the Oscar Peterson trio recording
I am listening to at the moment, with piano across the centre, bass on
one side and drums on the other.


As has been pointed out, the *low* bass is centred, which is not
noticeable due to the lack of localisation below 100Hz. Here's a clue
- why do you think the THX '5.1' crossover point is set at 80Hz?

I thought you were supposed to be a professional fader jockey?
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #172   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Sun, 13 Mar 2005 21:28:40 +0200, "Iain M Churches"
wrote:

it allowed him to differentiate between an oboe and a cor anglais.
Are you among those who can differentiate between the two?


Yes, the cor anglais has a more extended timbral structure.

Can you tell the difference between a violin and an alto violin (viola)
playing the same note?


Yes, there is extra 'richness' to the viola sound.

Can you differentiate between a tenor and alto
saxophone playing in the same register?


Usually, although I find that more difficult.

If not, the psychologist must be right:-)


Only if he meant that some people (such as recording engineers) tend
to suffer premature deafness.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #173   Report Post  
Patrick Turner
 
Posts: n/a
Default


I should be interested to hear of your disc cutting experience.

Iain

Oh, and Phil.....Please try to be civil. Your insults and expletives do
nothing to strengthen the content of your posts. In fact quite the reverse.
I am happy to discuss disc cutting with you, but if you are unable to do so
in a civilised manner I shall reach the conclusion that you are either
socially
challenged or in need of professional help, and consign your posts to
a killfile, as so many others on RAT have done.


Your request, advice, and following reply from Phil
won't make it seem any easier to converse with Phil.
His snr is so high barely any sound he makes is intelligible.
And this is on an audio site!

Patrick Turner.




  #174   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Phil Allison" wrote in message
...

Your obvious autism is not an excuse.


English is not my first language, yet still my vocabulary seems to
exceed yours, Phil. I do not need to resort to expletives to state a
point.

You make no further mention of helium cooling,



** High time for you to explain what seems a joke to most.


Please do some research, or take the trouble to contact Neumann
or Westrex. They will confirm my statement.


** Go and get utterly ****ed - you posturing, pommy arsehole.

You are one stupid, arrogant, irrational bloody public menace.

No wonder you actually admire excreta like the Turneroid.


PT's posts are both helpful and informative, like many others on this
group.

** The idea is to get ****ing useless imbeciles like you OFF usenet
altogether !


I think all you will achieve by your singular behaivour is marginalisation.
I shall not read your posts or bother to reply to your desperate
utterances in the future.


Iain


  #175   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...

I thought you were supposed to be a professional fader jockey?


Then in this too you are mistaken:-)
I am a professional recording engineer.

Cordially,

Iain





  #176   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 02:35:02 GMT, "Ian Iveson"
wrote:

"Phil Allison" wrote

A periodic discontinuity requires an infinite number of terms
to resolve.


** No real world one does - since it is band limited.


The real world is continuous. There are no band limited
discontinuities.


Sure there are - the atmosphere is a low-pass filter.

As you were told earlier in the thread.


A periodic discontinuity requires an infinite number of terms to
resolve. True

A simple fact that counters the insane rubbish you are preaching.


No, I said "A periodic discontinuity requires an infinite number of
terms to resolve.", which is true.


But a sufficiently large finite number is more than adequate for human
perception.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #177   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Patrick Turner" wrote in message
...

I should be interested to hear of your disc cutting experience.

Iain

Oh, and Phil.....Please try to be civil. Your insults and expletives do
nothing to strengthen the content of your posts. In fact quite the
reverse.
I am happy to discuss disc cutting with you, but if you are unable to do
so
in a civilised manner I shall reach the conclusion that you are either
socially
challenged or in need of professional help, and consign your posts to
a killfile, as so many others on RAT have done.


Your request, advice, and following reply from Phil
won't make it seem any easier to converse with Phil.


I can see that you are right. He's "in the bin"

Iain




  #178   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
On Sun, 13 Mar 2005 21:28:40 +0200, "Iain M Churches"
wrote:

it allowed him to differentiate between an oboe and a cor anglais.
Are you among those who can differentiate between the two?


Yes, the cor anglais has a more extended timbral structure.


That sounds like a quote from Groves :-)

Can you tell the difference between a violin and an alto violin (viola)
playing the same note?


Yes, there is extra 'richness' to the viola sound.

Can you differentiate between a tenor and alto
saxophone playing in the same register?


Usually, although I find that more difficult.

That is generally thought to be the easiest of the three tests.

If not, the psychologist must be right:-)


And yet, with your seemingly high level of perception,
you still prefer SS? Hmm:-)

Cordially,
Iain


  #179   Report Post  
Phil Allison
 
Posts: n/a
Default


"Iain M Churches"
"Stewart Pinkerton"


I thought you were supposed to be a professional fader jockey?


Then in this too you are mistaken:-)
I am a professional recording engineer.



** While that may constitute an explanation - it is far from a valid
excuse.




............. Phil




  #180   Report Post  
gcrain
 
Posts: n/a
Default

Amazing how the simpletons resort to acting like 2 year olds everytime.
I just wish you could get odds on it in Vegas.



  #181   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
Usually, although I find that more difficult.

If not, the psychologist must be right:-)


Only if he meant that some people (such as recording engineers) tend
to suffer premature deafness.


No, he was referring to levels of perception, which is a totally
different thing.

A recording engineer with premature deafness is unlikely
to record a classical work which wins the coveted
Grand Prix du Disques.

However, premature deafness would probably not be much of a
hindrance when sticking on the stamps in the post room at RBS.
Don't give up your daytime job:-)


Cordially,

Iain




--

Stewart Pinkerton | Music is Art - Audio is Engineering



  #182   Report Post  
Ruud Broens
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
: On Mon, 14 Mar 2005 12:40:12 +1100, "Phil Allison"
: wrote:
..
:
: ** How bizarre - cold air would do.
:
: Helium has much higher heat capacity than air, and much lower mass. It
: is an excellent (and inert) cooling medium, and is used in many
: industrial processes. &
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

& something our 'knowledgeable' mr. Allison does not seem to know..
Rudy


  #183   Report Post  
Ruud Broens
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
: On Mon, 14 Mar 2005 02:35:02 GMT, "Ian Iveson"
: wrote:
:
: "Phil Allison" wrote
:
: A periodic discontinuity requires an infinite number of terms
: to resolve.
:
: ** No real world one does - since it is band limited.
:
: The real world is continuous. There are no band limited
: discontinuities.
:
: Sure there are - the atmosphere is a low-pass filter.

Especially noticable in winter, in foggy weather. Vegetation and
especially snow change sound transfer characteristics outdoors, too.

:
: As you were told earlier in the thread.
:
: A periodic discontinuity requires an infinite number of terms to
: resolve. True
:
: A simple fact that counters the insane rubbish you are preaching.
:
: No, I said "A periodic discontinuity requires an infinite number of
: terms to resolve.", which is true.
:
: But a sufficiently large finite number is more than adequate for human
: perception.

...what would you know about perception, Stewart ??
Rudy
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering


  #184   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 10:17:50 +0200, "Iain M Churches"
wrote:


"Stewart Pinkerton" wrote in message
.. .

I thought you were supposed to be a professional fader jockey?


Then in this too you are mistaken:-)
I am a professional recording engineer.


Well, let's agree that you got paid for it.... :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #185   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 10:27:46 +0200, "Iain M Churches"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Sun, 13 Mar 2005 21:28:40 +0200, "Iain M Churches"
wrote:

it allowed him to differentiate between an oboe and a cor anglais.
Are you among those who can differentiate between the two?


Yes, the cor anglais has a more extended timbral structure.


That sounds like a quote from Groves :-)


John Groves? Never heard of him.

Can you tell the difference between a violin and an alto violin (viola)
playing the same note?


Yes, there is extra 'richness' to the viola sound.

Can you differentiate between a tenor and alto
saxophone playing in the same register?


Usually, although I find that more difficult.

That is generally thought to be the easiest of the three tests.


Fair enough, it's not a comparison I hear very often.

If not, the psychologist must be right:-)


And yet, with your seemingly high level of perception,
you still prefer SS? Hmm:-)


Indeed, as do the vast majority of experienced audiophiles, who are
used to hearing whole orchestras from the best seats...........
--

Stewart Pinkerton | Music is Art - Audio is Engineering


  #186   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 14:50:23 +0100, "Ruud Broens"
wrote:

"Stewart Pinkerton" wrote in message
.. .
: On Mon, 14 Mar 2005 02:35:02 GMT, "Ian Iveson"
: wrote:


: No, I said "A periodic discontinuity requires an infinite number of
: terms to resolve.", which is true.
:
: But a sufficiently large finite number is more than adequate for human
: perception.

..what would you know about perception, Stewart ??


More than anyone who prefers tube amps, obviously! :-)

--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #187   Report Post  
Ruud Broens
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
: On Mon, 14 Mar 2005 14:50:23 +0100, "Ruud Broens"
: wrote:
:
: "Stewart Pinkerton" wrote in message
: .. .
: : On Mon, 14 Mar 2005 02:35:02 GMT, "Ian Iveson"
: : wrote:
:
: : No, I said "A periodic discontinuity requires an infinite number of
: : terms to resolve.", which is true.
: :
: : But a sufficiently large finite number is more than adequate for human
: : perception.
:
: ..what would you know about perception, Stewart ??
:
: More than anyone who prefers tube amps, obviously! :-)
:
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

....but did you perceive, i put _in_ that sentence, to get this
thread-header posted some more ? ;-)
Rudy


  #188   Report Post  
Stewart Pinkerton
 
Posts: n/a
Default

On Mon, 14 Mar 2005 20:47:44 +0100, "Ruud Broens"
wrote:

: ..what would you know about perception, Stewart ??
:
: More than anyone who prefers tube amps, obviously! :-)


...but did you perceive, i put _in_ that sentence, to get this
thread-header posted some more ? ;-)


Nope, but this thread is being transmitted at several MHz, which I
hope even you wouldn't consider to be perceptible by humans. DOH! I
did it again............................
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #189   Report Post  
Joseph Meditz
 
Posts: n/a
Default

"No, an impulse is not composed of waves, and has no Fourier
transform."

YIKES!


Have you got a point to make?


"You may contrive an approximation, perhaps using a delta
function,
but a simple impulse is a singularity, has no period, and
therefore
no transform."
YIKES!


Have you got a point to make?


http://mathworld.wolfram.com/F=ADour...nction.h=ADtml


You looked it up. Well done!


Have you got a point of your own to make, or are you just confirming
mine?


You twice said that an impulse has no Fourier Transform. That is
incorrect, false, untrue, and dead wrong. That is my point. Get it?

And no, I am not confirming your point. I am refuting it.

Cheers,
Joe

  #190   Report Post  
Ruud Broens
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
: On Mon, 14 Mar 2005 20:47:44 +0100, "Ruud Broens"
: wrote:
:
: : ..what would you know about perception, Stewart ??
: :
: : More than anyone who prefers tube amps, obviously! :-)
:
: ...but did you perceive, i put _in_ that sentence, to get this
: thread-header posted some more ? ;-)
:
: Nope, but this thread is being transmitted at several MHz, which I
: hope even you wouldn't consider to be perceptible by humans. DOH! I
: did it again............................
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

yep! & QED

;-)
Rudy




  #191   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Stewart Pinkerton" wrote in message
...
I thought you were supposed to be a professional fader jockey?


Then in this too you are mistaken:-)
I am a professional recording engineer.



Well, let's agree that you got paid for it.... :-)

Yep. Over and over and over again. For the whole
of my working life. I am offered more projects than
I can accept. I must be doing something right:-)


Iain


  #192   Report Post  
Ian Iveson
 
Posts: n/a
Default

You twice said that an impulse has no Fourier Transform. That is
incorrect, false, untrue, and dead wrong. That is my point. Get
it?


er...what point?

A simple impulse has no fourier transform, so the delta function is
used instead. The delta function is not a simple impulse. A simple
impulse is neither continuous nor periodic. The delta function is
both. The delta function is used because there is no fourier
transform of a simple impulse.

And no, I am not confirming your point. I am refuting it.


No, you are simply denying it. That is another difference you may
care to investigate. But mostly, you need to think.

cheers, Ian


  #193   Report Post  
Fabio Berutti
 
Posts: n/a
Default

Now You're all on my ground, f***wit or not... here they are, all the
thermal properties of air and helium @ atm. pressure and T=20°C or 100°C.
Use fixed width font to read the table. Data from a professional chemical
process simulation SW.

================================================== ============================ STREAM ID AIR-COLD AIR-HOT HELIUM-COLDHELIUM-HOT NAME PHASE VAPOR VAPOR VAPORVAPOR ----- TOTAL STREAM ----- RATE, KG-MOL/HR 1.000 1.000 1.0001.000 K*KG/HR 2.897E-02 2.897E-02 4.003E-034.003E-03 TEMPERATURE, C 20.000 100.000 20.000100.000 PRESSURE, KG/CM2 1.020 1.020 1.0201.020 MOLECULAR WEIGHT 28.972 28.972 4.0034.003 -------- VAPOR --------- SPECIFIC GRAVITY (AIR=1.0) 1.000 1.000 0.1380.138 CP, KCAL/KG-C 0.241 0.242 1.2251.225 DENSITY, KG/K*M3 1189.231 933.844 164.207129.012 Z (FROM DENSITY) 0.9998 1.0002 1.00041.0004 TH COND, KCAL/HR-M-C 0.02209 0.02726 0.127620.15315 VISCOSITY, CP 0.01792 0.02162 0.019690.02322It is to be pointed out that, when using these gases as a coolant, theirdensity is as important as their MASS specific heats, ie. we need toconsider the specific heat per unit VOLUME. Doing so, with reference tostandard conditions (20°C - 1 atm), we can see what follows:Air: 0.241 kcal/kg * 1.189 kg/m3 = 0.287 kcal/m3 (@ cond.)Helium: 1.225 kcal/kg * 0.164 kg/m3 = 0.201 kcal/m3 (@ cond.)Briefly, it takes (+/-) the same CUBIC METERS of air or helium to take awaythe same calories. The differences a1 - Helium thermal conductivity is six times higher, Cp is five timeshigher, density is seven times smaller: therefore, the overall heat transfercoefficient (OHTC) is much larger when using helium (say very roughly 6 * 5/ 7 = 4.3 times). This means that small, delicate objects that must beeffectively cooled but cannot be finned or sunk in a liquid coolant NEEDhelium. Using air they would simply run too hot.2 - Helium is as chemically inert as it can be, while air, and particularlymoist air, can corrode thin wires or the even thinner insulating lacquers,in the long run and at high temperature.AFAIK helium was used in some types of graphite-moderated nuclear reactorsas a kernel coolant to withstand the terrific heat release per element unitsurface, before liquid sodium proved to be an even better fluid in terms ofOHTC (but I don't think that a molten caustic metal at some 200°C would beso good to cool a recording lathe's coil...)I don't know how much this all has to do with tubes, indeed...CiaoFabio"Stewart Pinkerton" ha scritto nel messaggionews:uufa3157uhsmneq1of4sunsn2n6j4mvck3@4 ax.com... On Mon, 14 Mar 2005 12:40:12 +1100, "Phil Allison" wrote:"Iain M Churches" "Phil Allison" ** The cutter head may need cooling - but Helium is not a goodcoolant. The cutting stylus is in fact *heated* . The cutting stylus is indeed heated. The cutter head coil is cooled as required with helium. This is a fact which is well documented.** How bizarre - cold air would do. Helium has much higher heat capacity than air, and much lower mass. It is an excellent (and inert) cooling medium, and is used in many industrial processes. -- Stewart Pinkerton | Music is Art - Audio is Engineering

  #194   Report Post  
Ruud Broens
 
Posts: n/a
Default


"Ruud Broens" wrote in message
...
:
: "Stewart Pinkerton" wrote in message
: ...
: : On Mon, 14 Mar 2005 20:47:44 +0100, "Ruud Broens"
: : wrote:
: :
: : : ..what would you know about perception, Stewart ??
: : :
: : : More than anyone who prefers tube amps, obviously! :-)
: :
: : ...but did you perceive, i put _in_ that sentence, to get this
: : thread-header posted some more ? ;-)
: :
: : Nope, but this thread is being transmitted at several MHz, which I
: : hope even you wouldn't consider to be perceptible by humans. DOH! I
: : did it again............................
: : --
: :
: : Stewart Pinkerton | Music is Art - Audio is Engineering
:
: yep! & QED
:
: ;-)
: Rudy
:
:
....yeah, Phil, two can play that game.
;-)
Rudy


  #195   Report Post  
Fabio Berutti
 
Posts: n/a
Default


"Iain M Churches" ha scritto nel messaggio
...

"Phil Allison" wrote in message
...

Your obvious autism is not an excuse.


English is not my first language, yet still my vocabulary seems to
exceed yours, Phil. I do not need to resort to expletives to state a
point.

You make no further mention of helium cooling,



** High time for you to explain what seems a joke to most.


Please do some research, or take the trouble to contact Neumann
or Westrex. They will confirm my statement.


As I already posted, I don't know anything about lathes, but if the problem
is to cool something very small and very hot and it cannot be sunk in a
liquid, then helium is the way to go, and this is a purely physical issue
(I'm a chemical, not an electrical engineer).




** Go and get utterly ****ed - you posturing, pommy arsehole.

You are one stupid, arrogant, irrational bloody public menace.

No wonder you actually admire excreta like the Turneroid.


PT's posts are both helpful and informative, like many others on this
group.

** The idea is to get ****ing useless imbeciles like you OFF usenet
altogether !


I think all you will achieve by your singular behaivour is
marginalisation.
I shall not read your posts or bother to reply to your desperate
utterances in the future.


Iain





  #196   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Fabio Berutti" wrote in message
news

"Iain M Churches" ha scritto nel messaggio
...

"Phil Allison" wrote in message
...

Your obvious autism is not an excuse.


English is not my first language, yet still my vocabulary seems to
exceed yours, Phil. I do not need to resort to expletives to state a
point.

You make no further mention of helium cooling,


** High time for you to explain what seems a joke to most.


Please do some research, or take the trouble to contact Neumann
or Westrex. They will confirm my statement.


As I already posted, I don't know anything about lathes, but if the
problem is to cool something very small and very hot and it cannot be sunk
in a liquid, then helium is the way to go, and this is a purely physical
issue (I'm a chemical, not an electrical engineer).


Hello Fabio,

Thanks for your info on helium. It is a well documented fact that it is
used for cutter head cooling. But, Phil couldn't be expected to know that
if he had not actually been involved in the disc cutting process, which
very few people, with the exception of studio personnel, have.

Iain


  #197   Report Post  
Ian Iveson
 
Posts: n/a
Default

Now You're all on my ground, f***wit or not... here they are, all
the thermal properties of air and helium @ atm. pressure and
T=20°C or 100°C.
Use fixed width font to read the table. Data from a professional
chemical process simulation SW.
...


Now we know! Thanks for the rigour, Fabio.

cheers, Ian


Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Some Recording Techniques kevindoylemusic Pro Audio 19 February 16th 05 08:54 PM
Artists cut out the record biz [email protected] Pro Audio 64 July 9th 04 10:02 PM


All times are GMT +1. The time now is 05:17 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"