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X-Factor: Muso's in silent protest!



 
 
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  #31 (permalink)  
Old December 19th 10, 11:11 PM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
Dave Plowman (News)
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Posts: 5,872
Default X-Factor: Muso's in silent protest!

In article ,
JNugent wrote:
I can still cope with pretty well any 1/4" tape here at home, with the
exception of 30 ips.


You can just spin them into the computer at 15ips and adjust the sample
rate to convert them...!


Ok if you just wanted to listen to it. But the equalisation will be wrong,
and you'll lose the extreme bottom end. So I'd advise anyone with 30 ips
tapes to have them copied properly - since they are likely to be of
important stuff.

--
*Some days you're the dog, some days the hydrant.

Dave Plowman London SW
To e-mail, change noise into sound.
  #34 (permalink)  
Old December 20th 10, 11:05 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
tony sayer
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Posts: 2,042
Default X-Factor: Muso's in silent protest!

In article , Dave Plowman (News)
scribeth thus
In article ,
Keith G wrote:
The biggest problem with digital is that it's all or nothing and when
DAB radio craps out it makes the most hideous noise followed by silence.


Dunno why DAB is so bad in this respect. FreeView audio just mutes if it
loses the signal. My DAB car radio switches to FM. ;-)

Lucky -U-...

run 4 it
--
Tony Sayer

  #35 (permalink)  
Old December 21st 10, 08:42 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
Eiron[_2_]
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Posts: 39
Default X-Factor: Muso's in silent protest!

On 20/12/2010 00:11, Dave Plowman (News) wrote:
In article ,
JNugent wrote:
I can still cope with pretty well any 1/4" tape here at home, with the
exception of 30 ips.


You can just spin them into the computer at 15ips and adjust the sample
rate to convert them...!


Ok if you just wanted to listen to it. But the equalisation will be wrong,
and you'll lose the extreme bottom end. So I'd advise anyone with 30 ips
tapes to have them copied properly - since they are likely to be of
important stuff.


Just checked - an old copy of Wireless World had a DIY tape recorder design
with pre/de-emphasis time constants inversely proportional to the tape
speed.
So the frequency response will be correct when playing back at a
different speed.
(Dolby would still screw it up though.)

--
Eiron.
  #36 (permalink)  
Old December 21st 10, 09:21 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
David Looser
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Posts: 1,883
Default X-Factor: Muso's in silent protest!

"Eiron" wrote in message
...
On 20/12/2010 00:11, Dave Plowman (News) wrote:
In article ,
JNugent wrote:
I can still cope with pretty well any 1/4" tape here at home, with the
exception of 30 ips.


You can just spin them into the computer at 15ips and adjust the sample
rate to convert them...!


Ok if you just wanted to listen to it. But the equalisation will be
wrong,
and you'll lose the extreme bottom end. So I'd advise anyone with 30 ips
tapes to have them copied properly - since they are likely to be of
important stuff.


Just checked - an old copy of Wireless World had a DIY tape recorder
design
with pre/de-emphasis time constants inversely proportional to the tape
speed.
So the frequency response will be correct when playing back at a different
speed.
(Dolby would still screw it up though.)


It's not quite that simple. There are a number of factors that affect the
frequency response of an analogue tape recorder, the simplest is the
"rate-of-change-of-flux" issue that causes a 6dB/octave rise in output with
rising frequency, this is counteracted by a simple 6dB/octave roll-off in
the replay amplifier. So as far as that is concerned replaying the tape at
half-speed merely results in a 6dB overall reduction in output level.

However there are also things that affect the HF response:- head inductance,
the effect of tape bias, sinx/x loss as the recorded wavelength approaches
the width of the head-gap etc. To counteract these the 6dB roll-off in the
replay amplifier is levelled out at a frequency dependant on the tape speed,
and HF boost is applied to the record amplifier. The frequency at which the
replay amp response levels out is specified as a time constant, and there
are different standards for this; NAB CCIR IEC etc. To get the correct
frequency response it is important to ensure that a tape is replayed with
the correct standard selected in the replay amp. The HF boost applied to the
record amp (and also sometimes in the replay amp) is simply adjusted to give
the flattest overall response.

So even without Dolby if you want a technically correct replay it's best to
do it at the right speed, and for copying a professionally-recorded master
tape that's really the only acceptable method. However for amateur tapes of
less than perfect technical quality half or double speed copying is quite in
order IMO. For the tapes I mentioned I just applied whatever
frequency-response corrections appeared to my ears to give the most natural
sound to the recording.

David.
..


  #37 (permalink)  
Old December 21st 10, 09:44 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
Dave Plowman (News)
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Posts: 5,872
Default X-Factor: Muso's in silent protest!

In article ,
Eiron wrote:
Ok if you just wanted to listen to it. But the equalisation will be
wrong, and you'll lose the extreme bottom end. So I'd advise anyone
with 30 ips tapes to have them copied properly - since they are likely
to be of important stuff.


Just checked - an old copy of Wireless World had a DIY tape recorder
design with pre/de-emphasis time constants inversely proportional to the
tape speed. So the frequency response will be correct when playing back
at a different speed. (Dolby would still screw it up though.)


The use of Dolby B (domestic) would be very unusual at 30 ips. As really
would be Dolby A. The main use of 30 ips was to get the best noise figures
without any reduction systems - and even then they had other disadvantages.

But I'd point out that in all my years around pro analogue tape recorders
in broadcasting, I've never used a machine capable of 30 ips.

--
*If God dropped acid, would he see people?

Dave Plowman London SW
To e-mail, change noise into sound.
  #38 (permalink)  
Old December 21st 10, 11:17 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
David Looser
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Posts: 1,883
Default X-Factor: Muso's in silent protest!

"Dave Plowman (News)" wrote

The use of Dolby B (domestic) would be very unusual at 30 ips. As really
would be Dolby A. The main use of 30 ips was to get the best noise figures
without any reduction systems - and even then they had other
disadvantages.


Dolby licensing prohibited the use of Dolby B on 15 and 30 ips tapes. The
"high-speed" (3.75, 7.5 and 15 ips) version of the series 75 Ferrograph with
Dolby B was required to disable the Dolby circuitry when 15 ips was
selected. And I agree the main reason for using 30 ips was to avoid using NR
at all.

David.


  #39 (permalink)  
Old December 21st 10, 06:06 PM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
David Looser
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Posts: 1,883
Default X-Factor: Muso's in silent protest!

"Dave Plowman (News)" wrote in message
...
In article ,
David Looser wrote:

Dolby licensing prohibited the use of Dolby B on 15 and 30 ips tapes.
The "high-speed" (3.75, 7.5 and 15 ips) version of the series 75
Ferrograph with Dolby B was required to disable the Dolby circuitry
when 15 ips was selected. And I agree the main reason for using 30 ips
was to avoid using NR at all.


One learns something knew every day - thanks for that. I've never owned a
Dolby B 1/4" machine -


There weren't many. Revox did a Dolby B version of the A77, but that was a
two speed (3.75, 7.5 ips) machine. There was no high speed (7.5, 15 ips)
version with Dolby B. The Ferrograph was the only 15 ips capable machine
with Dolby B that I'm aware of.

only cassettes.


There's little doubt that it was cassettes that made Dolby B a money-spinner
for Dolby.

But I do have a Dolby A/SR rack for
my machines.


I have a Dolby A unit, not that I use it much!

SR is brilliant.


My only experience of SR is in connection with 35mm film (analogue sound
tracks on 35mm cinema release prints have used SR noise reduction for some
20 years or so)

It's amazing what some firms chuck out. ;-)


As you say, some of the things that used to get slung in the skip at BT labs
when I worked there made me weep.


David.


  #40 (permalink)  
Old January 3rd 11, 09:16 AM posted to uk.media.tv.misc,uk.rec.audio,uk.rec.audio.vinyl
Eiron[_2_]
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Posts: 39
Default X-Factor: Muso's in silent protest!

On 17/12/2010 18:51, wrote:
I just came across this today while looking for John Cage records on
Amazon:

www.catm.co.uk

Some professional musicians are getting fed up with the amateurs on X-
Factor getting the Christmas No.1, so they've put out a recording of
John Cage's 4'33", this is a piece composed in 1952 which is for any
number of musicians to remain silent for 4 minutes and 33 seconds.

Only seems to be available as a download, it would be more effective
as a CD or even better on vinyl (you would get the crackle etc).


Anyone know what happened? I thought I heard it on the radio
but it turned out that it was not plugged in.

--
Eiron.
 




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