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Another observation about these apparently rare paper tape recordings made, 
I assume, on a Soundmirror machine. (the red tape boxes are all Soundmirror 
labelled). These recordings are very noisy. I'd read that paper based tapes 
were noisy partly because of the roughness of the paper backing, and I dont 
doubt  that's true.   But when one of the recordings finished and it went to 
blank unrecorded tape  I noticed a large drop in background noise.

Maybe the initial recorder had a magnetised tape path? I made a test 
recording on a blank piece of tape on a good modern recorder and while there 
was the expected extra "bias noise", the total noise was much lower than on 
the old recordings. Then I read somewhere that the original Soundmirror 
recorders used a permanent magnet erase head. I guess this would also 
explain the very high background noise.

Has anyone else experienced this much higher background noise on recordings 
made on Soundmirror machines?

Tim Gillett
Perth,
Western Australia


----- Original Message ----- 
From: "Richard L. Hess" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 17, 2018 8:08 AM
Subject: Re: [ARSCLIST] Soundmirror paper 1/4" tape


> Hi, Tim,
>
> The only thought I had is that there was moisture intrusion into the tape 
> pack at some point to cause this. This could have been moisture on its own 
> or with biological or chemical contaminants that acted like an adhesive or 
> caused the tape coatings to act like an adhesive.
>
> It is just a guess with no real science to back it up.
>
> Yes, I would try baking to separate, but that's not always useful, either.
>
> The other thing that has occasionally worked with blocked tapes is 
> chilling them for a while, both to drive out moisture and get some 
> micro-movement layer to layer which may "unhook" the little bonds.
>
> If you hear a zipper noise, you are damaging tape.
>
> Good Luck!
>
> Richard
>
>
>
>
> On 2018-10-16 4:58 PM, Tim Gillett wrote:
>> Hi Corey,
>>
>> No, definitely not normal sticky shed or even any stickiness.
>>
>> My tentative guess is that with time and pressure the rough surface of 
>> the paper backing has imprinted itself onto the adjacent layer's smoother 
>> oxide surface so that many tiny "interlock" or clasp points have formed. 
>> On the sections where the winds have separated without damage, the 
>> interlocks have released and now there is no longer a stiction in those 
>> sections. I can rewind the tape back from where the tape stopped and it 
>> winds perfectly. No stiction. For a paper tape, the pack is quite good. 
>> When I run the tape forward, as soon as it gets to the point where I 
>> stopped separating the wind, the adhesion resumes.
>>
>> It's complicated by various sticky tape splices which have gone gooey and 
>> oozed, causing adhesions at those points but that's a separate issue.
>>
>> Yes there are unrecorded sections which I can experiment with.
>>
>> Thanks,
>> Tim
>>
>>
>> ----- Original Message ----- From: "Corey Bailey" 
>> <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Wednesday, October 17, 2018 4:12 AM
>> Subject: Re: [ARSCLIST] Soundmirror paper 1/4" tape
>>
>>
>>> Hi Tim,
>>>
>>> It's hard to recommend a solution without visually assessing the 
>>> problem. For polyester base tapes that have layer-to-layer adhesion, I 
>>> usually have to bake them at a lowered temperature (118° F. or less) for 
>>> 6 to 8 hours and then I will check the tape again. For paper backed 
>>> tape, baking may not work. Is there an unrecorded section that you could 
>>> use for testing? For me, baking audio tape is reserved as a last resort. 
>>> Layer-to-layer adhesion is the one exception.
>>>
>>> Cheers!
>>>
>>> Corey
>>>
>>> Corey Bailey Audio Engineering
>>> www.baileyzone.net
>>>
>>> On 10/16/2018 6:11 AM, Tim Gillett wrote:
>>>> Thanks Gary,
>>>>
>>>> Yes having had experience with one tape like this 15 years ago (from 
>>>> the same person's archive) I'm aware of the centre track, the tracks 2 
>>>> and 3 capture and the azimuth corrector technique. It's just a shame I 
>>>> wasnt aware of this sticking problem back then as I guess if I'd 
>>>> unwound them then it wouldnt have been as much of a problem as has now 
>>>> become 15 years on.
>>>>
>>>> I only recently discovered that the tapes have been stored in less than 
>>>> ideal conditions with high humidity and evidence of mould on some tapes 
>>>> (but apparently not on any of these Soundmirror tapes that I can see.
>>>>
>>>> Yes hoping Richard Hess or maybe Peter Brothers might have experience 
>>>> with this sticky problem.
>>>>
>>>> Regards,
>>>>
>>>> Tim.
>>>>
>>>>
>>>> ----- Original Message ----- From: "Gary A. Galo" <[log in to unmask]>
>>>> To: <[log in to unmask]>
>>>> Sent: Tuesday, October 16, 2018 8:57 PM
>>>> Subject: Re: [ARSCLIST] Soundmirror paper 1/4" tape
>>>>
>>>>
>>>> Hi Tim,
>>>>
>>>> This is a strange problem. I've worked with quite a few Brush 
>>>> Soundmirror tapes in our archive, and the only spots where I found any 
>>>> sticking was on a couple that had leader tape spliced on at the 
>>>> beginning. But, it was confined to that spot, and not all the way 
>>>> through.
>>>>
>>>> Regarding playback on modern equipment, I use tracks 2 and 3 of a 
>>>> 4-channel head. They fit right over that single half track on the 
>>>> Soundmirror tapes. The stereo playback allows proper azimuth 
>>>> adjustment, and gets you inside of most of the edge curl that may have 
>>>> occurred. It may also get you inside any oxide shedding that may 
>>>> happen, if that stickiness is confined to the edges. Then I put the two 
>>>> channels through a phase corrector before summing them to mono.
>>>>
>>>> Richard Hess may be able to better address the sticking problem.
>>>>
>>>> Best
>>>> Gary
>>>>
>>>> Gary Galo
>>>> Audio Engineer Emeritus
>>>> The Crane School of Music
>>>> SUNY at Potsdam, NY 13676
>>>>
>>>> ________________________________
>>>> From: Association for Recorded Sound Discussion List 
>>>> <[log in to unmask]> on behalf of Tim Gillett 
>>>> <[log in to unmask]>
>>>> Sent: Tuesday, October 16, 2018 8:32:39 AM
>>>> To: [log in to unmask]
>>>> Subject: [ARSCLIST] Soundmirror paper 1/4" tape
>>>>
>>>> Hello,
>>>>
>>>> I'm having problems with some very early Soundmirror tapes using a 
>>>> paper backing, circa late 40's early fifties I guess. I suspect they 
>>>> havent been wound or played for many decades. They contain live 
>>>> recordings of mainly classical oratorio concerts.
>>>>
>>>> The tape wind is semi sticking to the next wind in varying degrees 
>>>> depending on the tape in question. With a couple I've been able to 
>>>> slowly wind them off without tape breakage or loss of oxide. Once they 
>>>> have been unstuck and spooled onto the take up reel they remain unstuck 
>>>> and play well. I've been able to repair old splices and clean off old 
>>>> spreading adhesive.
>>>>
>>>> But this one is more sticky and further into the reel I go it has 
>>>> started to really stick to the next wind and rip off small pieces of 
>>>> oxide (I guess more tension from being under a constant torque wind for 
>>>> many years has made the inner layers stick more to each other).
>>>>
>>>> Any hints on treating the tape to help it wind off without damage, or 
>>>> with less damage? Heat, humidity etc?
>>>>
>>>> Thanks,
>>>>
>>>> Tim Gillett
>>>> Perth,
>>>> Western Australia
>>
>>
>> ---
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> -- 
> Richard L. Hess                   email: [log in to unmask]
> Aurora, Ontario, Canada                             647 479 2800
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.