The widely used method for adjusting tape azimuth uses a stereo tape and an
oscilloscope, and adjusting the azimuth to make the 2 channels in phase.

That's fine, I'm sure, for a calibration tape, but to adjust to a
pre-recorded tape it is less than ideal because if the tape was already
recorded with an az error, this method will restore the correct phase at
the cost of a rolled-off high-end. I'd rather have the high-end.

The concept is to adjust the azimuth to the pre-recorded high
frequency tone on the pre-recorded tape. If no tone exists, it is not
uncommon to adjust by ear, using a scope to check phase of the program
material.

Mark


On Thu, 10 Jul 2003 15:53:24 GMT, wrote:


The widely used method for adjusting tape azimuth uses a stereo tape and an
oscilloscope, and adjusting the azimuth to make the 2 channels in phase.

That's fine, I'm sure, for a calibration tape, but to adjust to a
pre-recorded tape it is less than ideal because if the tape was already
recorded with an az error, this method will restore the correct phase at
the cost of a rolled-off high-end. I'd rather have the high-end.

wrote:

The widely used method for adjusting tape azimuth uses a stereo tape and an
oscilloscope, and adjusting the azimuth to make the 2 channels in phase.

Right.

That's fine, I'm sure, for a calibration tape, but to adjust to a
pre-recorded tape it is less than ideal because if the tape was already
recorded with an az error, this method will restore the correct phase at
the cost of a rolled-off high-end. I'd rather have the high-end.

No, if you get the correct phase, you will also get the correct high end.
The idea being that you are matching the azimuth angle of the gaps on your
playback head to that of the gaps of the recording head of the original machine.

If the angle is the same, the phase will be correct, and the comb filtering
will be minimized.

You can think of the comb filtering as being a side effect of the incorrect
phase, if you think of each track as being a bunch of little tracks together.
if there is phase error between those little tracks, there will be comb
filtering when they are summed together.

The two things go together.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

(Scott Dorsey) wrote:

The two things go together.

I see what you mean. My post was pointless. Thanks.

In article , Klay
Anderson wrote:

Actually, if it is a calibration tape, it is full track mono. Whatever width,
it's full track mono.

To be more precise, it began as full track mono. There are multitrack
alignment tapes that have had the appropriate guard bands erased.

--
Bob Olhsson Audio Mastery Recording Project Design and Consulting
Box 90412, Nashville TN 37209 Tracking, Mixing, Mastering, Audio for Picture
615.385.8051 FAX: 615.385.8196 Mix Evaluation and Quality Control
40 years of making people sound better than they ever imagined!

"Klay Anderson" wrote in message
...
In article ,
wrote:

The widely used method for adjusting tape azimuth uses a stereo tape and
an
oscilloscope, and adjusting the azimuth to make the 2 channels in phase.

That's fine, I'm sure, for a calibration tape

Actually, if it is a calibration tape, it is full track mono. Whatever
width,
it's full track mono.

It doesn't make too much sense to try to adjust azimuth on anything other
than a proper calibration tape. (And *who* remembers to swap spools and
perform another 'play' to avoid a fast rewind .. ? )

In article ,
wrote:
(Scott Dorsey) wrote:

The two things go together.

I see what you mean. My post was pointless. Thanks.

It's not obvious, though. There is a really neat paper from Jay McKnight
about azimuth error too.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article ,
Bob Olhsson wrote:
In article , Klay
Anderson wrote:

Actually, if it is a calibration tape, it is full track mono. Whatever width,
it's full track mono.

To be more precise, it began as full track mono. There are multitrack
alignment tapes that have had the appropriate guard bands erased.

I actually have some old STL and Nortronics tapes that were recorded
half and quarter track. You can even see the fringing with Magna-see.
I really should throw them away because they are worse than useless now,
and because of the fringing the low end was never trustworthy.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Mike Faithfull wrote:

It doesn't make too much sense to try to adjust azimuth on anything other
than a proper calibration tape.

For playback, I -always- use the tones on the tape to line the playback head
on my machine up with that of the original machine. If the original machine
is out of alignment, I want to match it.

On tapes without tones this can be an adventure. Last week I was dealing
with some quarter track 3 3/4 ips stuff recorded on a machine with just
about everything maladjusted. Since all the performers died decades ago,
a retake isn't possible.

(And *who* remembers to swap spools and
perform another 'play' to avoid a fast rewind .. ? )

What is wrong with fast rewind? You should store tails-out, though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 10 Jul 2003 14:22:57 -0400, (Scott Dorsey) wrote:

You can even see the fringing with Magna-see.

Wow. I haven't seen that stuff in decades.

Mark

Mark Stebbeds wrote:
On 10 Jul 2003 14:22:57 -0400, (Scott Dorsey) wrote:

You can even see the fringing with Magna-see.

Wow. I haven't seen that stuff in decades.

Tape Warehouse still carries it. Very handy to have on the shelf.
You can read your credit card numbers too.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

The widely used method for adjusting tape azimuth uses a stereo tape and
an
oscilloscope, and adjusting the azimuth to make the 2 channels in phase.



The calibration tape is monophonic.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty

wrote in message

(Scott Dorsey) wrote:

The two things go together.

I see what you mean. My post was pointless. Thanks.

You might have confused frequency response or phase with square wave
response. Adjusting heads for the best square wave response can be futile.

Are you SURE??

I know of no way to "erase guard bands" that would NOT knock of some high end ON the
track!

As I recall, Ampex actually recorded the tapes ON the format: ie, 16 track 2", 1" 8
etc.

I may have to bow to you on this one but your version rubs my gut wrong!

Most tapes are "FULL TRCAK", fringing compensated to the format they are intended
for...

Techmeister aka db

In article , Bob Olhsson
wrote:

In article , Klay
Anderson wrote:

Actually, if it is a calibration tape, it is full track mono. Whatever
width,
it's full track mono.

To be more precise, it began as full track mono. There are multitrack
alignment tapes that have had the appropriate guard bands erased.

--
David 'db' Butler, Consultant
Acoustics by db
"...all the rest are just brokers"
now on the web at http://www.db-engineering.com
Boston, Mass
Phone 617 969-0585 Fax 617 964-1590