Regarding Richard's Comment:
"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."
During my mastering years, transport guides and tape slit error can produce
dynamic azimuth problems that are difficult to solve: thatís because the
tape to playback azimuth relationship can change over time - depending on
how the tape edge follows the guides on the tape path. If you've tried to
do sum/difference nulls to optimize azimuth correction, and found that it
would change over the duration of the tape, you might have this issue. On
bad examples, I would have change the tape path guide to use the top of the
tape rather than the bottom - and often produce a more stable azimuth
correction for the length of the recording.
What's worse are compilation tapes or dubs of a comp'd tape where spliced
portions exhibit completely separate azimuth relationships - because each
recording was from a different tape. IN some cases different mixes
performed on different days are spliced together. A spliced master could be
corrected but a dub of a comp'd tape not very well.
Richard's other comment about 1" 2-track brought back some interesting
long-forgotten memories too. From time-to-time I had to recreate new
1/4masters from a 1" 1/4 track, low-speed "running master" used for cassette
duplication. Gap scatter and slitting errors become a *MUCH* bigger issue
at low speeds and on wide tape formats... not a pleasant task I can tell
Rob Poretti - Sales Engineer - Archiving
Cube-Tec North America LLC
Vox.905.827.0741† Fax.905.901.9996† Cel.905.510.6785
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Richard L. Hess
Sent: September 10, 2014 10:26 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] AZIMUTH (was recording "cleanup" plugins and 192/24)
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
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.
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
> 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
>>> 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
Quality tape transfers -- even from hard-to-play tapes.