Actually, Tom, I think "stretched" referred to the dynamic range of the final product; in the encoded state, a more appropriate term would be "shrunk", since that's what Dolby does when it encodes.
db

    On Tuesday, February 9, 2016 7:07 AM, Tom Fine <[log in to unmask]> wrote:
 

 Copying Dolby tapes WITHOUT decoding them was definitely the conventional wisdom in studios in the
70 and 80s, as I recall. I think it was Dolby's recommended M.O.

Question - where did the term "stretched" come from in relation to Dolby encoding? What was being
"stretched"? Certainly not the average level, because Dolby calibration required closer attention to
VU meters (and keeping peaks out of the red zone), if you did it by the book. I always likened that
aspect of Dolby NR to typical UK and European disk-cutting, in that a quieter background allowed for
lower average levels. Of course with pop/rock records from the early LP days to the mid-60's,
there's the issue that UK and European versions often featured longer sides so had to be cut at a
lower average level to fit all the real estate. Anyway, though, "stretched"???

-- Tom Fine

----- Original Message -----
From: "Dave Burnham" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, February 09, 2016 3:43 AM
Subject: Re: [ARSCLIST] Playing reels backwards - separating myth from fact


Actually back in the Dolby A days I copied many encoded tapes without decoding them. On decoding,
the Dolby will address ALL of the hiss regardless of how many generations there are. There will be
losses such as cumulative frequency response errors and compounded distortion but those would happen
anyway, even if you decoded and encoded for every dub. If you don't decode/encode when you copy,
you'll avoid all of the errors introduced by the Dolbys themselves.

db

Sent from my iPhone

> On Feb 9, 2016, at 1:09 AM, Corey Bailey <[log in to unmask]> wrote:
>
> I need to remind everyone that I never made a backwards copy of an encoded (stretched) tape,
> regardless of the noise reduction employed. I was there when the "to decode or not decode"
> controversy was at it's height. My position was (and still is) to decode the original and
> re-encode the copy. Reason: If you make a copy of an encoded tape without decoding it, the copy
> will have baked in tape hiss that will ultimately not be affected by the noise reduction when
> applied for final playback. Thus, the copy will be nosier than if you decoded and re-encoded the
> copy.
>
> Cheers!
>
> Corey
> Corey Bailey Audio Engineering
> www.baileyzone.net
>
>> On 2/8/2016 9:19 PM, Jeff Willens wrote:
>> Actually, that was the one thing I always heard you could NEVER do with
>> Dolby encoded tapes -- dub them without decoding them.
>>
>> I'm going back 15 years or so to remember this, but it is possible I did not
>> decode the Dolby on some of the analog copies I made, probably for test
>> purposes. As I said, decoding backwards was not my preferred method, but no
>> one seemed bothered by my concerns. I did the dubs per the request of the
>> reissue producer. If there were residual decoding artifacts, I never heard
>> them or heard about them from the others involved.
>>
>> On Mon, 8 Feb 2016 21:23:34 -0000, Ted Kendall
>> <[log in to unmask]>  wrote:
>>
>>
>>> This runs counter to my own experience. Firstly, one great benefit of Dolby
>>> A was that straight copies of encoded tapes could be made without decoding,
>>> provided that the reference tones were retained on the copy, so there was no
>>> need to decode as part of the dubbing process. Secondly, to decode a Dolby A
>>> tape on reverse play is just plain wrong - the attack and decay
>>> chracteristics of the system are asymmetrical, so the decoding will be
>>> wrong, no matter how much you have finessed the other parameters.
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Jeff Willens"<[log in to unmask]>
>>> To:<[log in to unmask]>
>>> Sent: Monday, February 08, 2016 1:22 PM
>>> Subject: Re: [ARSCLIST] Playing reels backwards - separating myth from fact
>>>
>>>
>>> I should think the net gain depends on the type of music involved. Back at
>>> Universal, I was asked by a producer to make 1:1 analog copies of album
>>> masters played in reverse to be sent out for mastering. The thinking was
>>> exactly as you describe: sharper transients, better bass response and
>>> definition,etc. Since these were all reggae albums from the 70s and 80s,
>>> they felt it was worth the effort.
>>>
>>> In my own crude testing, I found that, aside from making sure the channels
>>> were consistent (something one can easily overlook), I also found azimuh to
>>> be the crucial factor in achieving any success, Many masters were Dolby
>>> encoded, which gave me much pause, but no one else was concerned about it (I
>>> figured decoding between the two tape machines was the least of all evils).
>>>
>>> Was there a difference? Hard to say. I believe there was a slightly better
>>> result from  reverse transfer, but nothing drastic. And definitely nothing
>>> that couldn't be got with skillful use of modern compression and EQ.
>>> =========================================================================
>>