That is elegant, Eric! Kudos!

Now, what you need is a midi encoder on the first head and a midi drive
on the second and record a midi track as you go along...

With StereoTool on cassettes, you can see the cyclical azimuth wander on
the virtual "strip chart" display. I don't know if it addresses that in
its azimuth adjustment, but it's a good guide to keeping things centered
within the smaller wobble envelope.

Cheers,

Richard



On 2014-09-10 5:49 PM, Eric Jacobs wrote:
> I reluctantly describe a process that we¹ve used on mono tapes
> with country-laning. It¹s tedious and problematic, but it can
> be better than aligning the azimuth just once at the beginning of
> a tape. We¹ve only resorted to this process a few times, it¹s
> hardly a ³production² process.
>
> In essence:
>
> 1. We play the tape back with a stereo headblock that is fitted
> with a precision vernier azimuth knob. The precision vernier
> azimuth knob allows you to read the relative azimuth adjustment
> that you¹ve made at any time. This is the actual headblock we
> use to do this (a fantastic sounding headblock as well):
>
> http://www.ataestuder.com/technical/shro-explained/
>
>
> 2. As the tape is playing we note the times and values for the
> azimuth knob. This can be a very slow process since we need to
> stop the tape to take the time and azimuth reading and write
> it down. We also record how slowly or quickly we should change
> the azimuth in seconds. Did I say ³tedious²? It really is.
>
> 3. We stuff the times and azimuth values into a spreadsheet to
> calculate the relative azimuth changes. We use a spreadsheet
> to calculate the changes because if you accidentally change
> the azimuth in the wrong direction, you actually make things
> worse.
>
> 4. Switch to a mono headblock that has an identical precision
> vernier azimuth knob.
>
> 5. Play the tape and make the azimuth changes according to the
> spreadsheet.
>
>
> I¹ll be the first to admit that there are all kinds of issues
> with this process, just to name a few:
>
> a. mechanical backlash in the azimuth adjuster
> b. only works for gross changes in azimuth over the course of
> playback
> c. cannot deal with continuous real-time changes in azimuth
> d. a mistake in calculating the relative azimuth is worse than
> no azimuth adjustment at all
> e. prone to human error during playback
> f. requires great care and patience
> g. effort is only justifiable on special/important recordings
>
>
> Again, I mention this process as a method of problem solving, and
> would never advocate this process as ³best practice².
>
> Eric Jacobs
>
> _________________________
>
> Eric Jacobs
> Principal
> The Audio Archive, Inc.
> 1325 Howard Ave, #906
> Burlingame, CA 94010
>
> tel: 408-221-2128
> [log in to unmask]
> http://www.theaudioarchive.com/
>
> Disc and Tape Audio Transfer Services and Preservation Consulting
>
> Please consider the environment before printing this email.
>
>
>
>
> On 9/10/14, 7:25 AM, "Richard L. Hess" <[log in to unmask]> wrote:
>
>> Hi, Andrew and Tom,
>>
>> I am (very) slowly working towards a paper on azimuth.
>>
>> The full-track mono tape is, of course, the hardest to play from an
>> azimuth perspective (of the common formats)--I hate to think about the
>> 1-inch two-track!
>>
>> Transport guidance is a huge issue and I have found that the Studer A80
>> is magical in that regard--and the Studer A810, not so much. The Sony
>> APR-5000 is between the two.
>>
>> For those of us who have taught ourselves how to adjust azimuth by ear
>> (sort of the same thing as focusing a camera lens in many ways), we do
>> not need crutches, but I have come to realize that using a two-track
>> head for "factory workers" might be beneficial.
>>
>> For one project I proposed (but we chose not to implement) a wide/narrow
>> head for full track mono. We batted around a few different
>> configurations--including a long discussion with Greg Orton. I was
>> thinking of something like 0.120 and 0.04. The nice thing is even if
>> things go south, you still have a good percentage of the highs on the
>> 0.04 track, albeit noisy.
>>
>> With that said, for oral history cassettes, I use, in addition to manual
>> azimuth adjustment, the azimuth compensation feature of
>> www.stereotool.com. This allows excellent channel summing for improved
>> noise, assuming both channels were recorded.
>>
>> There is a similar feature in iZotope RX Advanced.
>>
>> Cheers,
>>
>> Richard
>>
>>
>>
>> On 2014-09-10 7:51 AM, Tom Fine wrote:
>>> Hi Andrew:
>>>
>>> It's interestng you bring up this topic. I was just reading the book
>>> that comes with the new Beatles In Mono LP box and they talk
>>> specifically about azimuth on the full-track tapes. Despite the fact
>>> that these mono masters were made in-house at Abbey Road, most of them
>>> on the same machines, the mastering engineer said he had to adjust
>>> azimuth on the fly as records were being cut, especially with the later
>>> albums where mono mixes were done days or months apart. His point was,
>>> azimuth was specific to each track on some albums. He had made notes and
>>> used a gauge-based azimuth adjustment on his Studer A80 playback deck,
>>> so he was able to make precise tweaks as the tape rolled between cuts,
>>> according to the book text.
>>>
>>> I was taught, with full-track azimuth, that you really have to adjust to
>>> ear, how the top end sounds best. Keep in mind that time-damaged tapes
>>> and poorly slit tapes will likely "country lane" through the transport
>>> and wreak havoc with azimuth. Adjusting tones at the head of the
>>> full-track tape (when they exist) is somewhat helpful, but ears need to
>>> be the final judge.
>>>
>>> Azimuth is a tricky thing and I'm still learning about it after 40 years
>>> of playing tapes. What I have learned is that it's really critical to
>>> solve the azimuth puzzle in the analog domain because problems can't be
>>> satisfactorily fixed in the digital domain.
>>>
>>> For old full-track tapes, I am curious about using the center two tracks
>>> of a 4-track quarter-inch machine. I haven't done much with this, but
>>> when there are tones on the tape, you can get a scientific azimuth
>>> adjust with a scope. Many old tapes are edge-damaged and I wonder if
>>> it's better not to play the outer edges of the tape. However, the
>>> effects of country-laning may be even worse if you're grabbing two
>>> narrow bands of signal and either combining them or not.
>>>
>>> If you want to hear a prime example of azimuth issues, get a copy of the
>>> "Sun Records Greatest Hits" LP that was sold on Record Store Day this
>>> year. The tapes were clearly and audibly played back with a 2-track head
>>> and either were in such poor shape that they couldn't go through the
>>> transport correctly or the playback engineer was inept. In any case,
>>> with many of the songs, if you combine them to mono, they flange, "phase
>>> effect" and go in and out of treble cancellation, telltale signs of
>>> being played out of azimuth. If you listen on a stereo cartridge and
>>> don't combine to mono, it's not as bad, it just sounds like bad
>>> edge-warp. I think it was inept playback all around, but I've never
>>> handled the tapes. I do bet that they'd sound better if played back
>>> either through a narrow-width single head capturing the middle 1/2 of
>>> the tape height or with the middle two tracks of a 4-track quarter-inch
>>> head with azimuth constantly monitored on a scope and tuned to ear.
>>>
>>> By the way, even with the less than ideal playback and remastering, the
>>> tunes on that Sun LP jump right out the speakers, still hot and rockin'
>>> to this day.
>>>
>>> -- Tom Fine
>>>
>>> ----- Original Message ----- From: "Andrew Dapuzzo"
>>> <[log in to unmask]>
>>> To: <[log in to unmask]>
>>> Sent: Wednesday, September 10, 2014 7:34 AM
>>> Subject: Re: [ARSCLIST] recording "cleanup" plugins and 192/24
>>>
>>>
>>>> While I understand the importance of capturing output "above 20kHz"
>>>> with
>>>> the aforementioned tools, are there any tools available to help with
>>>> azimuth adjustments? Older recordings, especially those made in the
>>>> field
>>>> with machines that have been "banged up", may be recorded with azimuth
>>>> that
>>>> is slightly off. Therefore, the higher frequencies may be lost or
>>>> diminished if playback is not adjusted to the exact azimuth of the
>>>> original
>>>> recording. Is the only tool available our ears listening as we
>>>> manually
>>>> adjust the azimuth?
>>>>
>>>> On Fri, Aug 29, 2014 at 6:18 PM, John K. Chester <[log in to unmask]>
>>>> wrote:
>>>>
>>>>> At 04:49 PM 8/29/2014, Tom Fine wrote:
>>>>>
>>>>>> John, is there a modification for to remove those noises? Do 3rd
>>>>>> party
>>>>>> electronics also carry those noises or are they something with the
>>>>>> power
>>>>>> rails under the transport? Sorry if these are ignorant questions,
>>>>>> I'm not
>>>>>> that familiar with the innards of ATR's.
>>>>>>
>>>>>
>>>>> I suspect this is neither the list nor the proper subject heading for
>>>>> discussing such a highly technical issue, but here's a brief answer:
>>>>>
>>>>> I have never tried to clean up an ATR with stock electronics,
>>>>> although I
>>>>> have a good idea of where to start. I have no data on 3rd party
>>>>> electronics other than Plangent's. When I got the Plangent
>>>>> electronics to
>>>>> be clean enough for our purposes, I stopped worrying about the
>>>>> problem.
>>>>> Plangent does use a preamp in the headblock with a cable running
>>>>> directly
>>>>> to our box, which helps keep things clean.
>>>>>
>>>>> I do find it a bit odd that folks doing 192k transfers often don't
>>>>> seem to
>>>>> worry about how much signal gets from the tape to the tape machine
>>>>> output
>>>>> above 20 kHz, and how much noise in that region comes from the machine
>>>>> rather than the tape. There are useful signals up there, and we know
>>>>> that
>>>>> if the transfer captures them they can later be used to improve the
>>>>> quality
>>>>> of the audio below 20 kHz that we can actually hear.
>>>>>
>>>>> -- John Chester
>>>>>
>>>>>
>>>>>
>>>>> ----- Original Message ----- From: "John K. Chester"
>>>>> <[log in to unmask]>
>>>>>> To: <[log in to unmask]>
>>>>>> Sent: Friday, August 29, 2014 4:33 PM
>>>>>> Subject: Re: [ARSCLIST] recording "cleanup" plugins and 192/24
>>>>>>
>>>>>>
>>>>>> At 05:06 PM 8/29/2014, Shai Drori wrote:
>>>>>>>
>>>>>>>> So if I turn the display off the 28.8 kHz goes away?
>>>>>>>>
>>>>>>>
>>>>>>> No, that noise on an ATR is actually coming from the reel motor
>>>>>>> drivers. The display generates other noise which starts somewhere
>>>>>>> in the
>>>>>>> mid-50's of kHz and has lots of harmonics.
>>>>>>>
>>>>>>> Turning off the display removes a lot of the noise spikes in the
>>>>>>> audio
>>>>>>> output but not all of them.
>>>>>>>
>>>>>>> -- John Chester
>>>>>>>
>>>>>>
>>>>
>>>>
>>>
>> --
>> 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.
>>
>
--
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.