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Hi Jamie,

Regarding my previous post, if these tapes are in fact Stenorette tapes, they will hum like a swarm of bees. I recently transferred about 10 of these reels and had to get rid of the hum in all of them. There was also a lovely 16kHz tone going right across the top of it all. You’d have a field day with these. 

Jeff


On Sat, 13 Jul 2019 00:06:22 -0400, Jamie Howarth <[log in to unmask]> wrote:

>If there’s hum in the recording or if you like send me a 192/24 sample right from the playback and I’ll see if we can make a quick utility for you.
>
>Jamie Howarth
>Plangent Processes
>
>Please pardon the mispellings and occassional insane word substitution I'm on an iPhone
>
>> On Jul 12, 2019, at 21:58, Tim Gillett <[log in to unmask]> wrote:
>> 
>> 
>> I'm not familiar with the "gliding stretch" of Adobe Audition but if
>> it allows you to set (by ear or even better by a reference on the tape
>> such as hum) a start speed and  end speed then assuming a linear
>> increase in speed between those two end points, I guess it would 
>> replicate the original recorded speed.  I'd first make the assumption
>> that the original recorded speed didn't deviate due to slippage,
>> battery fade etc. Only if the speed was obviously inconsistent after
>> the initial correction of start and end points would I attempt further
>> corrections.  
>> 
>> It wasn't just cheap/battery powered  machines which used the rim
>> drive system. On the Continent from the mid 1950's,
>> Philips, Grundig and perhaps others used rim drive in mains powered
>> dictation machines  with essentially constant speed AC drive motors.
>> Grundig tended to use their own proprietary tape cassette, and non
>> standard reels, but the Philips models I'm familiar with used two 3"
>> standard 1/4" reels inside a clear "cassette".  The larger inner hub
>> size was used. These machines  come up on Ebay.  Many were
>> valve(tube) based machine. Philips continued the rim drive principle
>> though to a 1/8" tape in another type of cassette, and then on to the
>> tiny "mini cassette", also rim drive.
>> 
>> https://obsoletemedia.org/el-3581/
>> 
>> Tim
>> 
>> ----- Original Message -----
>> From:
>> "Association for Recorded Sound Discussion List"
>> <[log in to unmask]>
>> 
>> To:
>> <[log in to unmask]>
>> Cc:
>> 
>> Sent:
>> Fri, 12 Jul 2019 16:41:07 -0400
>> Subject:
>> Re: [ARSCLIST] Reel-to-Reel tape problem
>> 
>> Hello, J.D.,
>> 
>> I tried thinking this problem through a while ago and it hurt my
>> brain. 
>> You've heard from three experts who all said basically the same 
>> thing--with which I concur.
>> 
>> What I thought I would add is a little thought experiment.
>> 
>> These machines did not have a capstan and they pulled the tape by a 
>> motor attached to the takeup reel. For some reason it has been
>> referred 
>> to as "rim drive" perhaps because the motor often contacted a rubber 
>> surface on the rim of the reel table to provide a "gearing" ratio
>> from 
>> the motor to the reel table, rather than being directly attached to
>> the 
>> spindle.
>> 
>> So, let's assume that we have a constant speed motor that can deliver
>> 
>> infinite torque (bear with my and hold your "tsk tsks"). If that were
>> 
>> the case, you could calculate the actual speed by knowing the radius
>> of 
>> the tape pack at time of recording, the speed of the motor and pi. As
>> 
>> the takeup reel filled up, the tape speed would increase, so if
>> you're 
>> listening on a capstan driven machine, the pitch would drop. Let's
>> call 
>> this calculation (A).
>> 
>> BUT, the motor does not have infinite torque. As the radius of the 
>> takeup reel tape pack increases, the moment arm gets longer meaning
>> that 
>> the same amount of holdback tension may cause the motor to slow down
>> a 
>> bit as it can't deliver all the torque that would be required. So
>> this 
>> adjustment factor could be figured out, but the speed at the end of
>> the 
>> tape will fall short of what you calculated in (A) above. Let's call 
>> this adjustment factor (B).
>> 
>> So, at this point, the speed at any given point is (A) - (B).
>> 
>> Now, some odd things enter in that will change this. As the (gasp
>> zinc 
>> carbon flashlight) batteries discharge, the motor will not be able to
>> 
>> deliver as much torque as the batteries will deliver less current and
>> 
>> their voltage will drop compared with fresh batteries, so we have a 
>> third factor.
>> 
>> And if this unknowable was not enough, the holdback tension was
>> provided 
>> by pressure pads--usually against the heads--so this creates multiple
>> 
>> additional factors for affecting speed:
>> --the calendaring/polish of both tape surfaces will affect the
>> friction.
>> --the environmental temperature and humidity will affect the
>> friction.
>> --the cleanliness of the guides/heads will affect the friction.
>> 
>> So, there you have a quick snapshot of the dynamics of this system
>> and 
>> why fixing it in post in software is the best alternative.
>> 
>> I reiterate what Ted Kendall said, "there were myriad reel-drive 
>> Japanese recorders around at the time, all of which were different 
>> between samples, never mind designs." And I might add, there were 
>> differences with the same recorder based on tape type, climate 
>> conditions, and battery condition. A fair number of these recordings 
>> originated in Vietnam in my experience, but thankfully a large number
>> of 
>> the ones I have received were recorded with capstan machines. the
>> Craig 
>> 212 was a classic of the era with a capstan.
>> 
>> Cheers,
>> 
>> Richard
>> 
>>> On 2019-07-12 3:53 p.m., Scott Phillips wrote:
>>> These would have been rim drive recorders, without a capstan drive
>> roller. There is no fixed speed, it was determined by reel motor
>> torque and the diameter of the amount of tape on either reel at any
>> moment. Good luck with that, software is about your only available
>> practical tool I know of..
>>> 
>>> 
>>> Best regards,
>>> 
>>> Scott Phillips
>>> 
>>> 
>>> -----Original Message-----
>>> From: Association for Recorded Sound Discussion List
>> [mailto:[log in to unmask]] On Behalf Of J. D. Mack
>>> Sent: Friday, July 12, 2019 1:30 PM
>>> To: [log in to unmask]
>>> Subject: [ARSCLIST] Reel-to-Reel tape problem
>>> 
>>> I'm looking for some advice/info. I sometimes transfer reel-to-reel
>> tapes to CD or digital files for my customers. Frequently, I receive 3
>> inch tapes from the 1960s that start at one speed and gradually speed
>> up or slow down substantially as the tape plays. The speed range is
>> usually between 1 7/8 and 3 3/4, but never landing on either speed. I
>> can correct for this using Adobe Audition's gliding stretch, but it
>> takes quite a bit of trial and error. What sort of tape player would I
>> need to hunt down to play these tapes correctly without having to
>> resort to a software solution? My customers never have any idea what
>> brand and model was used to make the recordings.
>>> 
>> 
>> -- 
>> 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.
>> 
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