Re: [ARSCLIST] Audograph disc

[Robert J Hodge <rjhodge@xxxxxxx>]

At least the Grey machine runs on ac power. The rim drive tape recorder
motor had no governor and if the D cell battery ran low, the motor speed
would change accordingly. Some of those tape machines had a "speed
control" rheostat to further muddy up the waters. Not to mention reels
with slightly different sized hubs and tape thicknesses. 

Bob Hodge

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of Richard L. Hess
Sent: Friday, October 17, 2008 8:30 AM
To: ARSCLIST@xxxxxxxxxxxx
Subject: Re: [ARSCLIST] Audograph disc

At 01:37 AM 2008-10-17, you wrote:
>----- Original Message ----- From: "Michael Biel" <mbiel@xxxxxxxxx>
>>This was a constant linear speed machine.  There was no turntable
motor.
>>There was a small motor and rubber wheel in the arm which drove the
>>turntable.  The speed would constantly change from the outside to the
>>inside.  I'm not sure if they ever published the specs.  They would
>>never expect they would be played back on anything but their own
>>machines.
>"Constant linear speed machines" have, AFAIK, never done much except
>generate phonorecords which cannot be usefully played except on their
>own specific brand of machines! I have one of the UK make (forget its
>name) of the twenties...and playing it on a normal 78 machine is an
odd...
>but useless from a listening standpoint...experience...?!

I cannot imagine these being less predictable than the horrid, 
curse-on-the-audio-world "Rim Drive" capstanless, reel-to-reel 
(usually mini) audio tape recorders.

We've had reasonably good success with plotting the trajectory of the 
speed in "Elastic Audio" in the more-featured versions of Samplitude. 
DC6 has a similar feature (which was one of my main uses of that 
prior to the inclusion of "Elastic Audio" in Samplitude.

The nice thing about doing this correction in the computer is you can 
tweak it in an arbitrarily large number of segments and you can plot 
a line through that segment which is not constant speed. If the speed 
gods are with you, it can be as simple as a single sloped 
line...usually not with Rim Drive tapes.

Cheers,

Richard


Richard L. Hess                   email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information:
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.