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 ,
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."

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.

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