Techmoan: Pre-recorded Cassettes' Last Stand
 

In article , Johnny B Good
wrote:

I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on
an oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

The dc-blocking / highpass behaviour of audio systems in general tends to
'triangle wave' LF. I recall laughing out loud when I first saw how much a
QUAD 34 did this! 8-]

I'm not clear of the extent to which what you suggest would help much. It
might change the shape of the 'bumps'. But again, how many domestic
loudspeakers are phase-flat at LF?

That said, I'd be interested to know if anyone did as you ask, and how
effective it was.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

Techmoan: Pre-recorded Cassettes' Last Stand
 

On 14/02/2017 09:40, Jim Lesurf wrote:
In article , Johnny B Good
wrote:

I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on
an oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

The dc-blocking / highpass behaviour of audio systems in general tends to
'triangle wave' LF. I recall laughing out loud when I first saw how much a
QUAD 34 did this! 8-]

I'm not clear of the extent to which what you suggest would help much. It
might change the shape of the 'bumps'. But again, how many domestic
loudspeakers are phase-flat at LF?

That said, I'd be interested to know if anyone did as you ask, and how
effective it was.

But playing music backwards will reveal the secret messages and summon
the prince of darkness to release the magic smoke from your transistors
and the primordial slime from your electrolytics.

--
Eiron.

Techmoan: Pre-recorded Cassettes' Last Stand
 

On 14/02/2017 13:27, Eiron wrote:
On 14/02/2017 09:40, Jim Lesurf wrote:
In article , Johnny B Good
wrote:

I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on
an oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

The dc-blocking / highpass behaviour of audio systems in general tends to
'triangle wave' LF. I recall laughing out loud when I first saw how
much a
QUAD 34 did this! 8-]

I'm not clear of the extent to which what you suggest would help much. It
might change the shape of the 'bumps'. But again, how many domestic
loudspeakers are phase-flat at LF?

That said, I'd be interested to know if anyone did as you ask, and how
effective it was.

But playing music backwards will reveal the secret messages and summon
the prince of darkness to release the magic smoke from your transistors
and the primordial slime from your electrolytics.


Paul is Dead!

--
Graeme Wall
This account not read.

Techmoan: Pre-recorded Cassettes' Last Stand
 

In article ,
Johnny B Good wrote:
I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on an
oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

It was common practice to copy 1/4" tapes backwards. Although was never
quite sure if it worked any better. ;-)

--
*Your kid may be an honours student, but you're still an idiot.

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

Techmoan: Pre-recorded Cassettes' Last Stand
 

In article ,
Eiron wrote:
But playing music backwards will reveal the secret messages and summon
the prince of darkness to release the magic smoke from your transistors
and the primordial slime from your electrolytics.

;-) How things change in such a short time.

--
*It's this dirty because I washed it with your wife's knickers*

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

Techmoan: Pre-recorded Cassettes' Last Stand
 

"Dave Plowman (News)" wrote in message
...
In article ,
Johnny B Good wrote:
I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on an
oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

It was common practice to copy 1/4" tapes backwards. Although was never
quite sure if it worked any better. ;-)

As I recall they were copied head to tail (otherwise
how could the transfer personnel listen for sticky
edits or droupouts?) but stored tail out.

Copy facilities and archives still adhere to this.

Iain

Techmoan: Pre-recorded Cassettes' Last Stand
 

"Johnny B Good" wrote in message
...
On Sun, 12 Feb 2017 23:35:04 +0200, Iain Churches wrote:

"Jim Lesurf" wrote in message
...
In article , Iain Churches
wrote:
Prerecorded cassettes were always something of a compromise
(high-speed loop-bin duplication) but towards the end of that era,
chrome tape with Dolby B was starting to sound pretty good.

That reminds me that there was at least one company who did 'real time'
Cassette duplications for the sake of sound quality. I can't now recall
their name(s), though. Something like "White(something" perhaps was one
of them.

There were probably many. One I know of in North London was called
"SuperCassette" (original, eh?) They had a large room with dexion
shelves floor to ceiling with two or three realtime high-end cassette
recorders (Nakamichi or something similar) on each shelf. Each "aisle"
was fed by its own "master recorder" (Revox A77) with a studio copy of
the master running at 15 ips. The cassettes sounded quite good!


I wonder, seeing as they were going to such an extreme, whether they
also ran the master and slaves in reverse to mitigate the phase delay
'distortion' effect on low frequency square wave test signals which made
such test signals look like triangle waves on playback when viewed on an
oscilloscope, or did they just accept that despite this very visible
departure from the original waveshape, no one could distinguish the
direct versus the phase distorted magnetic recording playback by ear
alone anyway? :-)

The system was a simple one, and only needed two young
girls operators to keep it running. As soon as the EOT switch
clicked on the Revox one of them walked along the row,
ejecting the cassettes and putting in new ones.
The other dabbed the Revox replay head with a spot of Isoprop,
rewound the"master" and then helped with the casette replacement.
In a matter of minutes they were ready to go again. There was
a pair of headphones connected to the Revox (QC ?) I did
not see them used.

Iain

Techmoan: Pre-recorded Cassettes' Last Stand
 

In article ,
Iain Churches wrote:
It was common practice to copy 1/4" tapes backwards. Although was never
quite sure if it worked any better. ;-)

As I recall they were copied head to tail (otherwise
how could the transfer personnel listen for sticky
edits or droupouts?)

You'd not notice a sticky edit or a dropout on a tape being played
backwards? OK.

Did you really have many problems with dropouts?

--
*The problem with the gene pool is that there is no lifeguard *

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

Techmoan: Pre-recorded Cassettes' Last Stand
 

"Dave Plowman (News)" wrote in message
...
In article ,
Iain Churches wrote:
It was common practice to copy 1/4" tapes backwards. Although was never
quite sure if it worked any better. ;-)

As I recall they were copied head to tail (otherwise
how could the transfer personnel listen for sticky
edits or droupouts?)

You'd not notice a sticky edit or a dropout on a tape being played
backwards? OK.

Someone had to monitor the copy carefully from start to finish,
so there was no sense to listen to it backwards.
Also it was a good opportunity for the op to learn the
repertoire. Most studio trainees started as assistants in a
tape copying room.

Did you really have many problems with dropouts?

Not often. But still one had to listen for them. We had
a third party client who used a British tape (Ilford Zonal)
which was not as good as BASF, Agfa or Ampex.
Copies were often going to overseas agents who
used them to cut disc masters so they had to be pristine.

Iain

Techmoan: Pre-recorded Cassettes' Last Stand
 

In article ,
Iain Churches wrote:
Did you really have many problems with dropouts?

Not often. But still one had to listen for them. We had
a third party client who used a British tape (Ilford Zonal)
which was not as good as BASF, Agfa or Ampex.
Copies were often going to overseas agents who
used them to cut disc masters so they had to be pristine.

The answer then is to use decent tape and cut down on the labour involved
in checking copies.

BTW, if this client master on Zonal had dropouts, just what did your
trainee do about it? Phone them up and insist they arrange another
recording session?

--
*Monday is an awful way to spend 1/7th of your life *

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