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ARSCLIST  July 2008

ARSCLIST July 2008

Subject:

Re: Wire players

From:

Jim Lindner <[log in to unmask]>

Reply-To:

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

Date:

Sat, 26 Jul 2008 09:42:28 -0400

Content-Type:

text/plain

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Ah..... summer in North America.... short replies take a while - long  
replies take a long time - this is a long reply but I think the time  
has come to at least partially document efforts made by myself and Art  
Shifrin at my old company VidiPax more then 10 years ago. The lessons  
learned will likely be helpful to many on this list now, and perhaps  
more importantly to those who ponder these type of issues in general  
in the future - so I am counting on the Internet to index this somehow  
so someone who may have a need in the future can find it.

Based on a great deal of experience over time, I developed the theory  
that magnetic recorders (and frequently other media types as well)  
were in fact capable of far higher quality recordings then they were  
able to play back on the same machine. I slowly developed this theory  
during a period of about 5 years when I first started to do format  
migration work and was dealing with some very difficult issues in the  
video area - specifically relating to signal timing and playback which  
is of course critical in video. I noticed that while the machines  
could always record a signal - whether the machine could play back  
that signal (or another signal due to interchange issues) was an  
entirely different matter. This theory has proven to be correct over  
the years in many instances. Even if a machine was out of alignment it  
WOULD record in an out of alignment way - the trick then was to figure  
out how to play back that signal - and it was far more difficult in  
many instances to play back that signal with the electronics of that  
era.

When one thinks about that  now - it may be no great epiphany - but it  
was to me at that time because it made me realize that in fact  
virtually millions of recordings have NEVER been heard or seen with  
the same fidelity as had been recorded, and this occurred to me with a  
sort of overwhelming realization at that time. That meant that one  
COULD develop ways to play back recordings with modern electronics  
(modern by definition does not necessarily mean today "state fo the  
art" but could mean more modern relative to the time the technology of  
the recording was made - and sometimes in a "golden era" of  
electronics when certain gear that did particularly well with certain  
signal types was available).

When testing this theory with video, I found that it was sometimes  
true and sometimes not depending on a number of factors - but  
primarily one factor specifically in video that the electronics for a  
period got more tolerant (and therefore able to indeed play back  
better then the original recorder could) and then less tolerant - as  
state of the art came to mean that all electronic timings were perfect  
from first recording and so the playback electronics really did not  
have to be very tolerant at all (in the analog domain) because all of  
the recorded signals were in good shape (if nothing went wrong). So  
when a tape that was in crapola shape came for playback 30 years  
later, playback was exceedingly difficult because the electronics of  
that vintage expected everything to be perfect, there was no tolerance  
to speak of, and so it was a nightmare project to get a decent  
playback. This is still the case with it being far more difficult to  
play back a severely damaged digital recording then an analog one.

During this time Art Shifrin came to work for me at my company at that  
time - VidiPax. We were at the time business colleagues and friends  
(and that unfortunately is no longer the case). At that time we  
discussed this theory I had - which made sense to him. The business at  
that time involved playing back obsolete formats and Wire Recording  
playback was a format we supported. We used period wire recorders, but  
you did not need to be too good of an audio engineer to see that the  
playback electronics on those machines (either professional or  
consumer) was pretty awful. The transports were largely Rube Goldberg  
affairs if you look inside of one - and we both figured there had to  
be a better way. We decided to find out if my theory was true for Wire  
Recordings - even considering their age and low coercivity - and  
decided to build ourselves a test bed device to see what might be  
possible.  Now remember that this was for internal purposes only for  
our playback business - there was never any intention to actually sell  
one of these.

In earlier days Art worked for Ampex as a repair technician and knew  
the insides of the reel to reel decks cold. The Ampex decks were also  
in plentiful supply essentially for the asking, and both of us had  
very high regard for the quality of the Ampex playback electronics  
having a clean sound that was analog and appropriate for the playback  
of the wires - at least conceptually. There were many other questions  
however - such as heads.... Would standard playback heads playback the  
low level recordings from the wire? We did not know, but I reasoned  
that the worse case would be that the levels would be low and that the  
S/N would then be in the dumps - but we could deal with that through  
preamplification tweaking or through getting a custom head stack and  
preamp made if necessary (we of course had wire recorder heads and  
there are several expert head rebuilders around and could easily  
commission a new head with different characteristics and  
electronicsbased on the output level from the wire). We reasoned that  
worst case it would be no lower then the output from a turntable  
cartridge and we could easily deal with that if we needed to. We found  
to our delight that we did not have to go to these extremes, but that  
a standard full track head worked just fine with the standard  
electronics with just a few tweaks, provided that we could hold the  
wire in place (the moving of the wire across the head made all sorts  
of sonic problems as you might imagine). Art devised a very simple  
design whereby he glued tiny wedges directly to the head to hold the  
wire in precisely the same position. Think of tiny triangles placed  
against one another with the bare head inbetween. The wire was  
"encouraged" to stay in place by the tension place upon it - and it  
rode in the groove between the two triangle wedges. As you might  
imagine the wire had higher friction then a tape would, so we wore the  
heads down a bit faster - but we had plenty of cheap Ampex full track  
heads, plenty of super glue, and plenty of plastic wedges so it was  
not much of a problem.

We also decided immediately that the transport system should be  
capstan driven. Provided that the wire could be maintained at proper  
tension through the entire playback path we believed that we could get  
a much more consistent playback then period machines were capable of.  
This was found to be true. Art did a great job on the transport system  
spending a huge amount of hours and eventually we enlisted the  
services of a friend of his that had a small machine shop, and built  
some components to essentially do 2 things - one was to allow the  
capstan to move the wire consistently at speed, and the other was to  
move the wire at the take up position so that it was not deposited in  
one place. To do that we essentially took the idea from a deep sea  
fishing reel and had a bobbin type assembly that moved the wire  
forward and back as the reel turned automatically. This was a tricky  
bit but with some experimentation was shown to be more reliable in  
terms of constant speed over the head then moving the reel up and down  
(as is done in some commercial wire recorders).

Bottom line - it worked and the results truly amazed both of us. The  
theory was more then correct and the results really were amazing - we  
had expected better but what we got was so far better that we truly  
were astounded. There was no more sound that sounded like you were  
listening through a cereal box - the sound was almost always clear and  
with really decent frequency response.

Art left the company and I believe continued work on his own on the  
device. Art deserved Kudos for doing the work that he did, and   
continuing on his own. I have always referred this type of work when  
it showed up to him in ensuing years whether he realized it or not.  
There are no "plans" and there were no other machines that were built.  
I am absolutely positively convinced that if you want to really hear  
what a wire recording has recorded on it - this approach is the one to  
be followed. It will take some time and money to do - but you now have  
the advance knowledge that we did not have - that in fact it DOES work  
and is worth the effort. Try it - you too will be amazed. The recipe -  
several used Ampex decks - used but not abused. Access to a machine  
shop to make a few parts. A good understanding of electronics and the  
schematics to make a few tweaks that you will find you need, good  
mechanical ability, lots of coffee, and a great deal of time to fiddle  
with it. It will be worth your while.



Jim Lindner

Email: [log in to unmask]

   Media Matters LLC.
   SAMMA Systems Inc.
   450 West 31st Street 4th Floor
   New York, N.Y. 10001

eFax (646) 349-4475
Mobile: (917) 945-2662
Office: (212) 268-5528

www.media-matters.net
Media Matters LLC. is a technical consultancy specializing in archival  
audio and video material. We provide advice and analysis, to media  
archives that apply the beneficial advances in technology to  
collection management.

www.sammasystems.com
SAMMA Systems provides tools and products that implement and optimize  
the advances in modern technology with established media preservation  
and access practices.



On Jul 18, 2008, at 11:11 AM, Prentice, Will wrote:

> We're trying to decide whether to rebuild an old wire player (or  
> two) or
> start from scratch. Our maintenance engineer asks:
>
> "We have a small number of wire recordings in our collections, in a
> variety of formats. We'd be interested to know what solutions other
> archives have found for playing back wires. I know that there are old
> machines still available, and some commercial operators using them to
> make transfers, but have any of you built or commissioned new  
> machines,
> and how have you found the process? How do you handle different  
> formats
> - is it a good idea to have a separate machine for each format, or is
> one 'universal' machine possible? Are there outfits or operators  
> around
> selling new machines and what would be the likely costs?"
>
> All informed thoughts welcomed.
>
> Regards
>
> Will
>
> ..............................................
> Will Prentice
> Technical Services
> British Library Sound Archive    Tel: +44 (0)20-7412-7443
> 96 Euston Road                       Fax: +44 (0)20-7412-7416
> London  NW1 2DB                   http://www.bl.uk
> UK                                          http://cadensa.bl.uk  
> (online
> catalogue)
>
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