Film-Tech Forum ARCHIVE: Adjusting Red Reader Without Test Film

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Posted by Edward Jurich (Member # 1787) on 09-21-2004, 09:12 AM:

This is possible if you need to install a red reader and don't have the test films. It will be set close enough to get by until it can be set with test tracks.

Once the red reader is installed and connected to the sound system. Use a couple of pieces of wire and jumper connect the left and right channels of the reader output, connect left - to right - and left + to right + . You have now a left + right, or mono, signal. Using a monitor in the booth that has a good high end frequency response, adjust the red reader while running stereo trailers or a feature until you hear the most highs or cleanest crisp sound. Lock the reader into position while listening, to make sure it stays in position. Now remove the jumper wires on the reader output. What's happening here is when connected mono, the stereo tracks are out of phase until the reader is set correctly. When out of phase, the high end will cancel and the sound will be muddy. When the reader is correctly set the high end will jump in as you are adjusting.
This is an old broadcast trick I used to set playback tape heads in a pinch.
Don't forget that when adjusting the reader, not only do you have to move the reader to and from the LED to focus, you also have to rotate the reader some. When you get close, small adjustments will make a big difference.

Posted by Gordon McLeod (Member # 33) on 09-21-2004, 09:39 PM:

That is 100% done wrong
The only way to align a reader is the proper way and any other method will yeild far from acceptable results and is a discredit to the capabilities of the reproduced track

Posted by Mark Gulbrandsen (Member # 72) on 09-21-2004, 09:41 PM:

I'll second what Gord said regarding this. The only thing you might get right with that method is phasing. Heck even on a tape recorder you are not going to know if the EQ is set right or not....as the head wears and such.

Mark @ CLACO

Posted by Jack Ondracek (Member # 1466) on 09-21-2004, 10:37 PM:

Well, he's not 100% wrong... you missed what he said... "Based on his experience as a broadcast engineer". I used to do those kinds of adjustments all the time... mainly because some of the stations I worked for got scads of agency tapes... and some stuff from other stations in the market that didn't have NAB alignment reels. If you couldn't adjust for phase... or optimum hf response with mono heads, you'd get a wild mix of audio qualities... and if you weren't stereo... or didn't have a scope, your ear would be the only way to get it done. In a pinch, you can get a red reader reasonably close by using Edward's method... though I personally would worry about it until I could check it by proper methods. It's not perfect. However, I have been surprised at how close I've been able to get it.

On the other hand, you guys are absolutely correct regarding EQ... both with tape and analog readers... no way to do that without the right gear.

Posted by Peter Schoell (Member # 919) on 09-21-2004, 11:12 PM:

I have, in emergency situations, adjusted readers without equipment.
Exciter types, by viewing the light ( I usally use the lens not in service at the time) as it is projected on the film, then moving the lens until the projected light appears as sharp as it can be, then you have to guess on the azmith by twisting the lens until the light appears horizontal.
With reverse scans I've hooked up headphones to the center channel of the amp and "ear balled" the the light and the reader for the loudest and clearest sound.
These are only "get by" measures and always need to be re set with the proper equipment ASAP.

Posted by Sam D. Chavez (Member # 1841) on 09-23-2004, 12:10 AM:

Not to be accused of fostering bad practices, but the azimuth can be roughly set by switching the booth monitor to the surround channel and the cinema processor to optical stereo. Twist the reader lens for a null in the audio while running a mono test film like Cat. 69 Pink noise. There is no EQ needed in optical with reverse scan since it is flat out to at least 10khz so setting slit loss is optional.

Posted by Steve Kraus (Member # 476) on 09-23-2004, 07:27 AM:

Ah but the premise is no test film not no test instruments. So why not set up the scope for X/Y and hook an RTA on there? Wait for a presumably fairly mono dialog-only part of the track and get the azimuth. I once had to do a mag Lt/Rt printmaster that way. (They recorded tone but forgot pink noise.) You can kind of "earball" the HF but the RTA will help. Listen closely to each channel and make sure there is no sibilance. If this is a new reverse scan install on a previously conventional setup you know the HF has no where to go but down, down, down.

Is it right? Nope. Might it save the day? Yup.

Posted by Sam D. Chavez (Member # 1841) on 09-23-2004, 02:57 PM:

Steve,

I must assume in order to ear ball you must have a monitor of some sort. The mono sections of a release print, IE, the portions with dialog will suffice.

Posted by Tim Reed (Member # 137) on 09-23-2004, 04:59 PM:

Ditto to what Jack said. It's a good trick. I don't think Edward was saying it's an alternative to doing it right. Sometimes, you just gotta make the thing work because you never know what can happen in the field. Those last Cat. 69P's will all crap out when you least expect it, and before your restock arrives. Thanks, Edward.

Posted by Alexander Alves (Member # 1746) on 09-24-2004, 02:02 AM:

All these are only possible if the lateral guide roller has not moved and was aligned with test films .Aint it guys?

Posted by Dominic Espinosa (Member # 2122) on 09-24-2004, 03:27 AM:

In my experience if your latteral guide has drifted that much you'd be picking up a buzz from the shifting.
I used to work in a both with a screwed up exciter lamp white-light reader that always drifted. One of the first things I ever did there was A-chain on the #2 house.
I've gotten away with it on red LED reverse-scan readers on a soundhead that had no latteral drift, at least that I could tell. It wasn't perfect but it's all we could do to get the analog back up in that house.
Used a trailer clipping looped to adjust by.

Posted by Jack Ondracek (Member # 1466) on 09-25-2004, 02:01 AM:

Again, this is an area where the only way to get it done "really right" is to have the proper test gear and loops.

However... the presence of the DTS track has made lateral alignment so critical, you can generally set it up by rotating your adjustment one way until you hear the DTS track... then the other until you hear the sprocket holes... then setting the adjustment between the two.... and there's not much adjustment space between them. Chances are that once you put a scope on it, you'll be just about right on.

If you're going to use a trailer loop, at least make sure you have a BIG loop. The splice can throw the alignment off a bit on some older soundheads.