Film-Tech Forum ARCHIVE: Refersher on A-Chain

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Posted by Randy Stankey (Member # 64) on 01-26-2011, 05:35 PM:

Making tweaks to the A-chain after installing a new processor.
(Finally got rid of that Smart and put in a CP-650.)

I've got a question about how to get it right.

When running a movie, some scenes have poor dialog.
The level of the dialog gets very low, very hard to hear and there is some distortion that sounds kind of like bees buzzing.
(e.g. Like the sound you hear when you tune an AM radio partly off the station.)

This does not happen during the whole movie. Only certain parts with lots of effects in the sound track. Specifically outdoor, street scenes or driving in a car.

You can still hear effects, music and background sounds fairly well.

We do not have surround speakers. Only L/C/R+Sub.

If I could hear dialog in the surrounds, I'd know that my azimuth/focus are off. (Azimuth, primarily.) But, since I don't have surrounds, I can't really tell.

Is this effect what you would expect if the azimuth is off or is there something else I need to check?

T.I.A. [Smile]

Posted by Sean McKinnon (Member # 612) on 01-26-2011, 09:32 PM:

If you think your that far off in your alignment you could try swapping the Lt Rt inputs from the reader at the processor and see if you dialog comes back.

Posted by Bill Duelly (Member # 3612) on 01-26-2011, 10:16 PM:

The buzzing sound I found out to be one of 2 things: 1) the soundtrack itself is scratchy (which I would doubt since you said the other channels seem fine) 2) the other which I just found when doing an A-Chain with an LED reader, is that the High Frequency compensation level is set too high for the analogs to really handle (even though it may seem fine on the scopes). I just brought that level down and it solved the problem.

Posted by Monte L Fullmer (Member # 2797) on 01-27-2011, 03:31 AM:

Ya, sounds like the slit loss adjustment need a bit of tweaking...

Posted by Darryl Spicer (Member # 711) on 01-27-2011, 01:06 PM:

If you have a tight XY response on your scope...be sure to run the signal through the analyzer with a loop of pink noise to verify the high frequencies are not over peaking. Back them down a bit if they are high. The less you have to use the slit loss adjustment the better. Make sure the optics are clean before making the adjustments.

Posted by Randy Stankey (Member # 64) on 01-27-2011, 01:18 PM:

I will need to redo the A-chain and make the azimuth and focus adjustments better. I checked them with the scope and they are close but not quite there.

It's one of those things I don't do very often, anymore. Although it's not hard to do, it takes practice to get it just perfect and I am out of practice. I just need to put my mind to it and take my time.

Now, with the slit loss correction, the CP-650 does that automatically.
Are you saying that the thing sets itself too high? When I used to do this for Cinemark, the procedure was to find the "high point," if you will, then to back off just a hair. So, I assume you're telling me that I should let the processor find home then manually back it off a couple-few clicks. Right?

How far do you think I should back it off?

Posted by Scott Norwood (Member # 30) on 01-27-2011, 01:28 PM:

I assume that you have tried multiple prints to rule out printing issues or a bad mix, correct?

Posted by Darryl Spicer (Member # 711) on 01-27-2011, 01:42 PM:

quote: Randy Stankey
Now, with the slit loss correction, the CP-650 does that automatically.
Are you saying that the thing sets itself too high? When I used to do this for Cinemark, the procedure was to find the "high point," if you will, then to back off just a hair. So, I assume you're telling me that I should let the processor find home then manually back it off a couple-few clicks. Right?

Make your adjustments at the sound head and get the highest highs you can get on your anylizer and maintain a tight XY combination on your scope. Make sure the slit loss compensator is turned all the way down. Then make adjustments as needed on the compensator. You don't want the highs to peak above the other frequencies.

Posted by Randy Stankey (Member # 64) on 01-27-2011, 03:16 PM:

quote: Scott Norwood
I assume that you have tried multiple prints to rule out printing issues or a bad mix, correct?

The print in question was "Chairo Time." I have not ruled out the fact that there was a problem with the soundtrack on the print but I am not 100% satisfied with my A-chain, either.

I did a "good" A-chain but, when I had problems, I rechecked it and found that my azimuth was just a hair bit off. I tweaked it and the problem got better but it didn't go away completely.

Here's how I understand the process:

On the Dolby CP-650 processor, you set Dolby levels with the green Dolby Tone film then switch to the pink film. At that point, you adjust azimuth using the scope. Then you switch over to the internal RTA of the CP-650 and adjust focus until the curve is as flat as possible on both channels. Bounce back and forth between focus and azimuth once or twice to be sure that you haven't knocked one out of line while setting the other.

After that point, you tell the CP-650 to auto-adjust for slit loss correction.

I did it all up to this point as well as I could. When I had trouble with the print, I rechecked it and found that I was just a tiny bit off. I retuned and it got better but not all the way gone.

I ran a bunch of trailers and didn't notice any problem. It only occurred on that one print of "Cairo Time."

I am going to retune the A-chain one more time and I'm going to be sure that I make it as good as possible.

In the last 10 years, I have only done A-chains a few times. It's not hard to do but takes a certain touch to get really good results. You guys do this kind of thing all the time. If I give myself some time, I'll get it right. I'm just rusty, that's all.

When I first did it, I'd score myself as 8 out of 10. I retuned it and got it up to 9. Now I want to go for 10.

quote: Darryl Spicer
Make your adjustments at the sound head and get the highest highs you can get on your anylizer and maintain a tight XY combination on your scope. Make sure the slit loss compensator is turned all the way down. Then make adjustments as needed on the compensator. You don't want the highs to peak above the other frequencies.

Are you saying to just screw the automatic setting and do it the old fashioned way? I don't have a problem with that, really. I somewhat prefer to do it that way but I wanted to do it by the book the first time. Then, once I learn the process, I'll go off-script.

So, set the slit loss at zero, tune the azimuth and focus then adjust the slit loss for "flat" and back off a click or two? Is that right?

That's pretty much the way I learned it before.

Posted by Louis Bornwasser (Member # 3063) on 01-27-2011, 06:03 PM:

Stick with the Dolby instructions. You will need to be able to see the "x/y" and the response at the same time. Use a scope and an external analyzer for this. Louis Bornwasser

Posted by Darryl Spicer (Member # 711) on 01-28-2011, 03:00 AM:

quote: Randy Stankey
So, set the slit loss at zero, tune the azimuth and focus then adjust the slit loss for "flat" and back off a click or two? Is that right?

Yes it is best to get all you can out of the sound head adjustments and then tweak it in the processor.

Posted by Kenneth Wuepper (Member # 1174) on 01-28-2011, 09:09 AM:

It is wise to insert short pieces of "buzz" and "Left Right crosstalk" in the Pink focus and phase loop to be certain that everything stays centered.

Posted by Randy Stankey (Member # 64) on 02-02-2011, 01:51 AM:

I made some headway tonight.

I retuned the A-chain and I got it down real good. I basically took it all apart and started from scratch. It's the best job I've done in a long time.

However, the problem was still there! This was with a different print, too.
Checked the output of the processor with scope and meter. All channels were operating as they should. That puts it down to the amps and speakers.
I swapped out the amp for the center channel and the problem disappeared.

That problem is solved, I guess! [Smile]

Tomorrow, the Dolby Digital reader is due to arrive. Once I get that installed, I can go through the whole B-Chain procedure and make final adjustments on that and I should be good to go.

It's already sounding good with the EQ set to the curve. Once I get it EQed for the room the should should really pop!

Posted by System Notices (Member # 2357) on 07-09-2012, 04:17 PM:

It has been 523 days since the last post.

Posted by Victor Liorentas (Member # 5272) on 07-09-2012, 04:17 PM:

If I were to swap an OLD xl head with a 97 era PR 1014, will I need the a chain alignment redone? Is it possible to do this without messing it up?
I use SH1000 sound heads.

Posted by Tony Bandiera Jr (Member # 2365) on 07-09-2012, 07:25 PM:

Victor: Swapping the picture head should not affect the optical sound alignment at all. (Now if the picture head is not set right, ie it forces the film off center laterally as it enters the soundhead yeah there can be trouble.)

That said, I will say it never hurts to check it after the swap just to be sure.

And why the hell would you swap the older head you described in your email to me with a '97 piece of junk? [Big Grin]

The one you have is amongst the best of the xl's. (Cue Mark G. to complain about how the older castings suck. [Roll Eyes]

)

Posted by Victor Liorentas (Member # 5272) on 07-09-2012, 07:39 PM:

Thanks Tony! Well these old heads have warped a bit which has forced me to shim the front lens holder assembly. I now have great focus but I suspect I have some wear at the shutter gears because travel ghost is now apparent at the top and bottom on scope. Subtle but I cant remove it. I hoped this 97 head may be a tic better...

Posted by Tony Bandiera Jr (Member # 2365) on 07-09-2012, 08:00 PM:

Travel ghost at both top AND bottom of the image is due to the spring washer in the shutter drive wearing out. If you watch the gear and/or shaft on the shutter drive while it is running you can often see it bouncing in and out. I rebuild those drives, contact me by PM for details on a repair/exchange.

Posted by Monte L Fullmer (Member # 2797) on 07-09-2012, 08:03 PM:

Just have the paper thickness between the fibre drive gear from the SH1000 and the metal driven gear on the PR-1014 - you need that amount of play.

Posted by Robert Koch (Member # 3728) on 07-10-2012, 02:06 PM:

What can changing out a picture head have to do with A chain alignment.

Posted by Victor Liorentas (Member # 5272) on 07-10-2012, 02:49 PM:

I worried about messing up my analogue alignment.The last sprocket in the head feeds the sound drum after all.

Posted by Victor Liorentas (Member # 5272) on 07-18-2012, 01:07 PM:

I was discussing sound issues with Tony Bandiera Jr in some private emails recently.I had been frustrated with mono sound on original prints like Jaws. My print used to sound great on our old system which was the Smart Mod 8 [puke]

! It did mono sound very well but not Dolby SR or A.
Now with the CP55 mono has become flat and dull.This print has some curl from spending decades wrapped one way.This may be what was helping the Mod 8 before the A&B chain and CP55 installation.

My solution had been to turn down the treble dial on the center cat64b, turn off the surround amp and play it in SR! It may be crazy wrong but sounded far better than mono accept for some breathing on occasion and certain sounds like a whistle or shouting voices were harsh ,shrill.
I did test it after hours to make sure it was an improvement before showing it to the public! [Smile]

I thought a better idea might be to get a spare cat 64b card to manipulate and custom eq for a better mono sound.Bass is what was lacking here...Tony suggested getting a DBX 131 31 band eq unit which would give me more flexibility than the cat 64b.

Temporarily connected between the CP55 center channel output and amp. So I did just that and it really did the trick! I mainly cut the offending frequencies above 500 and boosted some lows a tiny amount. So using this eq for mono has worked very well to give this film a much more pleasing sound! [Smile]

I wish I knew exactly why the Mod 8 did such a great job in mono for this film but this DBX unit has beat that.
Just thought I would share this insanity in case anyone else has a problem with old mono soundtracks flat,bland or shrill.

I play it in real mono now and not SR!

Posted by Gordon McLeod (Member # 33) on 07-21-2012, 12:01 PM:

There is a mono eq pot that adjusts the curve on the 242 board

Posted by Victor Liorentas (Member # 5272) on 07-21-2012, 12:33 PM:

Yes but it's just like a tone control and does very little to make Jaws sound clear and have bass at the same time.
Perhaps it's the slight side to side curl on this old print that makes it sound poor but the eq I applied with the dbx 31 band unit really sounds great in this case!

Posted by Tony Bandiera Jr (Member # 2365) on 07-21-2012, 01:44 PM:

Gordon, yes you are right but as Victor pointed out, he needed finer control of the problem than the processor's controls can provide.

As much as I'd like to take credit for the outboard EQ idea, I actually ran into it first many years ago in a legit theater's system. They had 31 band EQ's on all three stage channels as they ran film and also used patch bays to switch between behind the screen speakers and others on and beside the stage. They could tweak the sound as Victor did if needed on older films and also for live P.A. use. The tech told me that 99% of the time on film the EQ's were left bypassed but that it saved his bacon on a few shows by having them available.

Posted by Louis Bornwasser (Member # 3063) on 07-21-2012, 07:09 PM:

Believe it or not, I have run some old mono films through a Shure M67 or M68 mixer. (Once upon a time we some these to bypass CP-55s). No EQ; sounded good! Louis

Posted by Brad Miller (Member # 2) on 07-21-2012, 09:55 PM:

quote: Tony Bandiera Jr
As much as I'd like to take credit for the outboard EQ idea, I actually ran into it first many years ago in a legit theater's system. They had 31 band EQ's on all three stage channels as they ran film and also used patch bays to switch between behind the screen speakers and others on and beside the stage. They could tweak the sound as Victor did if needed on older films and also for live P.A. use. The tech told me that 99% of the time on film the EQ's were left bypassed but that it saved his bacon on a few shows by having them available.

I installed that very thing at GCC Northpark around 1993 I believe it was. It was VERY convenient. I've also had that option in my various screening rooms since the 80s.

Posted by Tony Bandiera Jr (Member # 2365) on 07-21-2012, 10:44 PM:

See? Great minds think alike. [Smile]

When I get to finally build my screening room I am toying with the idea of doing the EQ's as well. [Smile]

Posted by Gordon McLeod (Member # 33) on 07-22-2012, 01:49 PM:

dolby made a unit i believe was the cat 42 that held a cat 22 and offered multiband expansion a lot of mixers used it i think there might have been a unit that the sr card would work with

Posted by Gordon McLeod (Member # 33) on 07-23-2012, 12:00 AM:

to think about it i play my mono stuff through a yellow kintek system

Posted by Martin McCaffery (Member # 37) on 07-31-2012, 11:32 AM:

The outboard EQ sounds like it may be the cure for my problems with mono tracks.
How does one go about installing it?

Posted by Louis Bornwasser (Member # 3063) on 07-31-2012, 11:38 AM:

Most Dolby processors have a "mono EQ" setting. (I can't remember if this is so for the CP650).

A tweak of this may be all you need. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 07-31-2012, 01:09 PM:

Louis, while you are technically correct many mono tracks can benefit from more comprehensive EQ than that limited function can provide. That is one reason why the install I mentioned did what they did. And why Victor followed suit.

Martin, the EQ I suggested is simply installed in the center channel output line of the processor, between the processor's output and the input to the center channel amp. Any tech can do in in less than 1/2 hour. I recommend the DBX unit I linked to as it is high quality and inexpensive as well as rack-mounted.

EDIT: Sorry, I sent the link to Victor by email, so everyone here this is one place to get it: Markertek

Posted by Martin McCaffery (Member # 37) on 07-31-2012, 02:18 PM:

Louis: Yes, I've played with the Dolby mono EQ, and the results were about the same as Victor's. Every mono print we've run in the last few years has been incredibly shrill, no matter what I do with the Dolby unit. As I mentioned earlier in a different thread, I have a 1950's sound test reel that sounds perfect with no adjustments, but a modern print just sounds like crap.

Tony: thanks, I'll look into this.

Posted by Victor Liorentas (Member # 5272) on 08-06-2012, 08:59 PM:

I ended up swapping the new PR 1014 head with my main projector and then swapped that in place of the other projectors flat gate old xl head. I will now use that head for parts. Sound align remained perfect on the main projector 1 but trailer projector 2 has lost it! Tried adjusting the position of the head but cant get Dolby level on the left channel. In fact almost no sound is coming from the left or center while in SR. So swapping heads can effect A chain align. Its mono only for that machine until a new A chain can be done. Picture quality is fantastic on both machines!

Posted by Steve Guttag (Member # 268) on 08-06-2012, 09:43 PM:

Martin...are you using red leds with older prints (non-cyan or high-magenta)? This can cause a shrillness (really cross-mod distortion).

Posted by Martin McCaffery (Member # 37) on 08-06-2012, 09:59 PM:

yes, we are using red leds. Anyway around this other then reinstalling the exciter lamps (not likely for single show).
Hoping the above EQ trick will help.

OTOH, we had a print of Goldfinger which came with a digital track and it, too, was shrill. I suspect they didn't do a remix for digital.

Posted by Steve Guttag (Member # 268) on 08-07-2012, 06:01 AM:

IR LEDs play the older tracks best. The IR leds will NOT play back cyan tracks though.

Posted by Scott Norwood (Member # 30) on 08-07-2012, 06:25 AM:

So, why is it that the CP650 does not seem to give a very clear trace on the scope when doing an A-chain? (No, adjusting the CRT optical "focus" control on the scope does not help.) I have seen this on two CP650s in two different theatres using the same scope, same pin-tip probes, etc. It's as if there is a bunch of digital background noise in the signal. By contrast, I can get a perfectly sharp image on the scope from a CP65 or CP500, using the test points on the preamp card.

This isn't really a problem...I'm just curious. And, no, I don't do A-chain alignments very often, and when I do it is typically with older equipment.

Posted by Martin McCaffery (Member # 37) on 08-07-2012, 12:05 PM:

Just ran a test of Dr Strangelove and it did not sound shrill even without tweaking.

I does sound cavernous, but as I recall, that's how it is supposed to sound.

So some mono's are better than others.

Posted by Tony Bandiera Jr (Member # 2365) on 08-07-2012, 12:57 PM:

Victor: You have another problem rather than physical misalignment. You have lost a connection from the reader in the process of the head swap. To move the film far enough out to lose one of the SVA tracks you would have a very visible deflection of the film as it threads through the reader. So double check the cabling to the reader and make sure nothing got pulled out or cut.

Scott: I have noticed the same thing on CP650s...it doesn't really affect the adjustment but it is annoying. If I had to guess, what that "noise" is from would be the digital chips in the processor. (Not the Dolby Digital system.) Try to ignore it. [Smile]

Posted by Rob J. Buskop (Member # 3338) on 08-10-2012, 02:10 PM:

Interesting to read all this.....
About 27 years ago I realised that all theatres, including my own private home cinema sounded worse on academy mono optical films after full modification of the sound system to Dolby.
This was the logical result of speaker replacement and B-chain equalising as per Dolby instructions.
So what I did, to anniliate this problem was the following:
On my (modified) CP-100 I installed some extra circuitry that, whenever mono-opt. is selected, takes the input and output of the Centre Cat.64B and switches these connections, via a relais, over to and external Cat.64 in it's original early Dolby housing.
With this equaliser I apply the necessary corrections to emulate the original sound character and quality of the well mixed mono soundtrack.
There's also a small switch on the front of the CP-100 that allows you to choose between the internal Cat.64B or the external Cat.64.
All other formats automatically switch to the internal equalisation.
Works like a dream and I like to consider this a very neat modification.
Must say that I've never ever been able to get a proper and excitingly good result with the extremely limited and poorly designed facility that Dolby supplied for mono tweeking on their later processors.

Posted by Victor Liorentas (Member # 5272) on 08-10-2012, 02:34 PM:

Yeah it's like the playback of mono films from the past was given little consideration.
Tony,Jarret brought in his scope and we verified that the left channel was still present but weak.The film looked to the naked eye to be running straight from the sprockets through the sound drum.
We adjusted laterally to regain the left channel but now the B.A.C.P LED seems to be weak and while balanced,both channels only get to one green light on Dolby level running the cat 69 loop.
Thing is LED strength was fine before the head swap? We already cut the resister wires a while ago.
Anyway sound for trailers on that projector now sounds decent in SR.
Need to get new LED units before the next A & b chain. When digital is installed...

Posted by Tony Bandiera Jr (Member # 2365) on 08-10-2012, 04:15 PM:

Victor:

How far out was the lateral? I am suspicious of why that was necessary, if anything more than say one full turn was required.

If the levels are even but very low then the LED position needs to be checked and tweeked. Loosen the LED base mounting screws slightly and while running CAT 69T (Dolby tone) twist the mount up and down for maximum level. Tighten the mount when you get max level. Be careful to get the LED itself as close as possible to the film, but not touching it.

You also need to check Illumination Uniformity with a CAT 566 loop and an RTA. You will have 6 tones, three per channel, that need to read within 1db of each other all the way across.

Posted by Victor Liorentas (Member # 5272) on 11-13-2012, 10:47 PM:

Been so busy with our recent booth modifications(Christie 2220,Doremi Showvault IMB and CP750)!
The 35mm machines got spread apart a bit, our CP55 eq disabled and connected to the CP750 inputs.
Also replaced both analogue leds or rather Rick Long Jr of Cinematronix did! [Smile]

Anyway all our formats sound fantastic now!
I still don't know what happened to the left channel on the problem machine after the xl head swap?
If I were reading the above posts,I would assume Mr Victor screwed something up when swapping heads [Cool]

But I swear I was insanely careful!
I think Tony is right that a connection was lost or led alignment got out of whack.

Posted by Manny Knowles (Member # 1171) on 11-15-2012, 09:22 AM:

quote: Victor Liorentas
Jarret brought in his scope and we verified that the left channel was still present but weak.

Signal present but weak -- But *which* signal? -- Could that simply be crosstalk from the other track?

Posted by Tony Bandiera Jr (Member # 2365) on 11-15-2012, 12:45 PM:

Good question Manny baby but it is all for naught now:

quote:
Also replaced both analogue leds or rather Rick Long Jr of Cinematronix did!
Anyway all our formats sound fantastic now!

From that result it tells me that either Victor knocked the LED out of adjustment or it coincidentally had some segments fail after the swap.

It is pretty easy to get "turned around" with reverse scan readers during alignment....that is why use of buzz track and CAT 97 is essential to make sure the lateral alignment is spot-on before going on to the next steps.

In general, for a new reader install I do the following:

"Eyeball" align the LED to the reader lens;
Run Dolby tone and adjust focus for peak output, then adjust LED for peak output;
Run Buzz track as quick check of lateral and set as required;
Run Pink noise and set focus and azimuth;
Run CAT 97 and Buzz track to verify crosstalk and lateral;
Run CAT 566 Illumination uniformity and re-adjust LED for peak level and even illumination;
And finally, run Dolby Tone to set the level.

That all takes less time that it sounds like.
I also keep my Buzz track and CAT 97 separate, I tried the combined loop and found it to be very annoying to work with.

Posted by Victor Liorentas (Member # 5272) on 11-15-2012, 01:11 PM:

To make room for the Christie 2220 I had to disconnect the B.A.C.P wires and relocate the conduit running to the amp rack.
It was all redone at great speed and we never did determine what went wrong after the xl head swap.
I like to think it was a coincidental failure of the led [Cool]

Posted by System Notices (Member # 2357) on 06-28-2017, 04:10 PM:

It has been 1686 days since the last post.

Posted by Victor Liorentas (Member # 5272) on 06-28-2017, 04:10 PM:

Has anyone ever tried removing the Academy filter from a Dolby CP 55 or 65 to improve the mono sound?

Posted by Stephan Shelley (Member # 8587) on 06-28-2017, 07:55 PM:

Don't know about removing but Cp55 & 65 do have a mono eq adjust that will brighten the sound.

Posted by Steve Guttag (Member # 268) on 06-28-2017, 09:44 PM:

The CAT242 allows removing the HPF via a jumper/link. There is a single-turn trimmer that will allow one to adjust the LFP.

Posted by Victor Liorentas (Member # 5272) on 06-29-2017, 11:12 AM:

What is LFP?

Posted by Steve Guttag (Member # 268) on 06-29-2017, 11:58 AM:

LPF = Low Pass Filter

Posted by Victor Liorentas (Member # 5272) on 07-10-2017, 02:33 PM:

I'm thinking of adding a diode on a spare control card which would activate the sub-woofers on mono,also thinking of removing the academy filter on a spare card for an experiment.
The goal is to get more impact on a mono film like Jaws.
I also have a 31 band eq on my center channel which I bypass when not needed.
I would love any opinions. [Smile]

Posted by Sam D. Chavez (Member # 1841) on 07-10-2017, 04:01 PM:

The last thing a mono track needs is more bass to go with the weak HF. But sometimes I think you pull our legs just for fun.

Posted by Victor Liorentas (Member # 5272) on 07-10-2017, 10:47 PM:

I wish I was having fun but no,I'm trying to make the best use of new speaker cabinets that were donated to the theater. I finally convinced the owners to let me put up a light and sound absorbent baffle wall behind the screen which it desperately needed.Sound and picture really improved!

The new speakers are basically becoming extra subs. They are ported with 2 15 inch woofers each,direct radiators. I decided to move the center speaker (Altec A4) to the right side next to the right screen channel. Then I positioned one of the new cabinets dead center and mounted the Altec horn on it. It is bi-amped with a new QSC amp.

The Altec bass bin is now acting as a sub-woofer.
When our tech comes to re-eq the auditorium,I wanted to try and improve our mono sound further if I can,while he's here.

It's decent now but I keep remembering how much better mono sound on Jaws in 35mm sounded on our old Smart Mod 8 processor. It was the only good thing about the Mod 8.
I hated the Mod 8 otherwise.

The Dolby cp55 modified to cp65 status with real SR was a great step up. I bought it 8 years ago along with a cat 700 and DA20. Except mono sound! It struggles to sound good in mono as compared to that crappy Smart Mod 8??
It took the theater owners 5 years to pay me back for the Dolby stuff. This is a struggling single screen neighborhood theater and I'm a struggling projectionist,trying to keep 35mm alive, lucky to still be sort of working in my beloved field. Most of my time since digital took over,is spent doing everything but projection work,or having fun.

Posted by Steve Guttag (Member # 268) on 07-11-2017, 07:14 AM:

Some may poke fun at me for saying it, but, if you want to play with mono a bit, get yourself a set of Kintek boxes (preferably the separates like the KT-21, KT22 and KT-24 but a KT-700 can work. The least important device in there is the KT-22 (Stereo-Phony-Izer). But the KT-21 will allow one to effectively expand the dynamic range of a mono track. The KT-24 does have the ability to generate a surround track (it was the best of the various offerings) but it also has a sub-bass generator too. It looks at the octaves that are on the track and then generates a version for the subwoofer. This also avoids picking up the shutters in the optical recorder that merely adding a subwoofer channel would do. Look up the DBX 100, 110, 120 if you want a more detailed explanation as it was used in the home stereo market.

Posted by Victor Liorentas (Member # 5272) on 07-11-2017, 09:24 AM:

Very interesting! Thanks Steve!

Posted by Tony Bandiera Jr (Member # 2365) on 07-21-2017, 10:33 AM:

I have (maybe had, since a lot of stuff got lost/damaged in the move to out here) one of the Ultra*Stereo boxes to make mono films into fake stereo...wonder how it would do for Victor's purpose? Anyone ever use one before?

If I still have it Victor it's yours if you want it.

Posted by Clint Koch (Member # 1179) on 07-21-2017, 04:06 PM:

Hey Tony, most JS-series are capable of that if the main frame has a JSYN module. I believe there was the JSYN-05 and the JSYN-10 but it has been a while. This was a synthesizer module for mono to sudo stereo. Should be in the manual section somewhere in one of the JS-Series manuals.

Posted by Tony Bandiera Jr (Member # 2365) on 07-22-2017, 02:48 PM:

Indeed you are correct Clint. I remember those two modules, and IIRC the box I had actually had the JSYN-05 card in it.

I miss the whole JS line of processors, they were very robust, clean sounding and had great Dolby NR emulation...and looked cool with the (Old JS "Sr." line, full plexiglass) covers.

Only "flaw" I found was that in the "Jr." series, it was possible to force one of the modules into the wrong slot (IIRC it was the surround decoder into the syn slot) which would damage the module electrically. One location I had used to burn them up constantly until they fired the moron who kept doing it. (You may even remember when I had to keep ordering replacement surround decoders for a while..)

I may get a chance tomorrow to see if I still have that box, and if so, I'll try to post pics and info on this thread.

Posted by Stephan Shelley (Member # 8587) on 07-22-2017, 03:07 PM:

If anyone is looking for modules for the JS series Sam Chavez of Bay Area Cinema Products has the stock of them. QSC is not supporting them. Sam also has some support for older Dolby Processors.

Posted by Clint Koch (Member # 1179) on 07-23-2017, 11:35 AM:

Sam is the MAN.