LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


[email protected]


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  June 2009

ARSCLIST June 2009

Subject:

Re: (Fwd) [ARSCLIST] Fwd: Recording Speed

From:

Michael Biel <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Mon, 22 Jun 2009 11:23:26 -0700

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (180 lines)

I understand what George is saying partially because I've seen him do it
and I am lucky enough to have one of his calibration discs.  In case
Doug and others still do not understand it, Doug's snip cut out the
important info and left in material that has no meaning without the
snipped part.  


In 1982 George commissioned a 7-inch pressing made of a 450 Hz. tone cut
at 45.0 RPM.  That disc can be played at any RPM and a frequency counter
will show a reading that is 10 times that RPM. (Play it at 73.7 RPM and
it shows 737.0 Hz.  78.26 shows 782.6 Hz. Etc.) If you have a frequency
counter handy, you can find what rotational speed you are using.  BUT,
if you include a few seconds of that calibration disc played on the same
turntable at the time of your transfer of the record you are working on,
then later on that frequency can be read with a counter and at any time
you can establish the rotational speed you used. It's like an audible
strobe disc that has the unique ability to be recorded, and it is as
accurate as your frequency counter is.  Sure, you could use a normal
test disc of, say, a 1000 Hz. tone, but George's disc is more directly
readable without using math to have to determine percentage of 1000 Hz.
whatever tone you used.

Mike Biel  [log in to unmask]  


 

-------- Original Message --------
Subject: Re: [ARSCLIST] (Fwd) [ARSCLIST] Fwd: Recording Speed
From: George Brock-Nannestad <[log in to unmask]>
Date: Sat, June 20, 2009 5:43 am
To: [log in to unmask]

From: Patent Tactics, George Brock-Nannestad

Hello,

Doug Pomeroy wrote (I have changed the sentence order to facilitate 
communication) :

> Forgive me, but I do not understand this. Could you explain it in 
> other words?
> Maybe it's simpler than I think.

> >
> > From: Patent Tactics, George Brock-Nannestad
> >
> 
> <SNIP>
> 
> > In use of the tape
> > as a secondary master, the content could be de-chipmunked by 
> > changing the
> > speed of the tape recorder, and the tape rewound to the calibration 
> > track,
> > which was measured by the counter and would give the rpm of the 
> > original
> > record at the de-chipmunked speed. This way, the actual transfer 
> > rpm is
> > completely immaterial and may be chosen for good tracking--we can 
> > still get
> > at the rpm, just as if we had access to the original record.
> 

----- I shall describe it as a witness would, who observed what I am
doing. 
However, it is fairly long, and those who detest long postings had
better 
leave now.

On the table we have a turntable with pickup, a record to be
transferred, a 
tape recorder (nowadays it would be some digital stuff), and my speed 
calibration disc SC. This disc has been prepared by cementing a
straightened-
out paper clip to the label, so that a piece of wire sticks up at the
center 
of the SC. This permits you to lift the SC and place it anywhere, even
on a 
rotating turntable.

The record to be transferred is placed on the turntable and the SC is
put on 
top of it - use either the edges or the wire. Start the turntable and
the 
tape recorder and let the pickup play the SC track - 5 seconds is
plenty. 
Lift off the pickup, lift off the rotating SC by means of the wire,
place the 
pickup on the rotating record to be transferred; a smooth operation that
does 
not take long. All the time the turntable rotates and the tape runs.
When the 
record has finished you can do two things: either just switch everything
off 
or replace the SC and play another 5 seconds at the end. When the tape
stops 
it contains the following: ca. 5 seconds of calibration signal followed
by 
some noises, followed by the transfer of the record (and then possibly 
another 5 seconds of SC for good measure). 

Now, the calibration signal on the tape is made to express in Hertz 10
times 
the rpm of the record - how this is obtained will be told below. This
means 
that if you measure 800 Hz as the frequency of the calibration signal,
then 
the turntable made 80 rpm at the transfer. If you fiddle with the speed
of 
the tape when playing the transfer until you get a reasonable sound (in
tune 
with something, for instance, or in a b key for a brass band), then you
have 
interpreted the transfer. If you want to know what rpm the turntable
should 
have had to provide this reasonable sound from the original record, you
go 
back to the calibration part of the tape and reproduce that with no
change of 
speed, i.e. with the speed you fiddled your way to for the transfer, if
you 
will get for instance 720 Hz, it would correspond to 72 rpm. Based on
the 
tape copy you will in other words be able to specify a speed for a
record you 
do not necessarily hold in your hand.

This means that you can do your transfer at e.g. 33 1/3 rpm, which
improves 
tracking and is a standard speed obtainable from almost all modern 
turntables. On reproduction of the tape you increase the speed of the
tape 
until your SC part of the transfer provides, say, 780 Hz, which will
then 
make the sound of the transferred record sound as if it was reproduced
at 78 
rpm. There are some de-emphasis issues that we do not need to go into
here, 
because they have nothing to do with pitching the record. The whole idea
is 
that you have the same change of pitch in the SC signal as you have in
the 
record signal, because they were transferred under the same speed
conditions.

By making the SC signal having the special relationship to rpm we avoid 
calculations that one would otherwise have to make. It is a signal that
will 
provide 600 Hz at 60 rpm, which is 1 revolution per second. This means
that 
the groove has to have 600 cycles on one revolution - it could be a
locked 
groove! When the turntable speed is increased, the frequency increases
in 
proportion. I did toy with the idea of having a special nickel turntable

platter (in effect a mother) made like a turntable mat with such a
locked 
groove at a radius that was outside any record that one might want to 
transfer. Instead of placing and lifting off a calibration record, one
would 
simply play the locked groove before (and after) playing the record.
Another 
way would be to have a timebase signal derived from the turntable
platter and 
record that on the second track of a stereo tape (or a third track when 
recording digitally). I have not myself used anything but my own Speed 
Calibrating Record SC-1. And nickel is not a good turntable mat
material, 
because good MC pickups are seriously attracted downwards to this
material.

I hope that this has clarified matters.

Kind regards,


George

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager