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
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 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
>> with machines that have been "banged up", may be recorded with azimuth
>> is slightly off. Therefore, the higher frequencies may be lost or
>> diminished if playback is not adjusted to the exact azimuth of the
>> 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
>>>> 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
>>> 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
>>> 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
>>> if the transfer captures them they can later be used to improve the
>>> 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.