Film-Tech Forum ARCHIVE: CP-500 & 4-Track Mag

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Posted by Don Furr (Member # 1469) on 04-25-2009, 12:56 PM:

I've looked at the operating manual and can't find anything about 35mm 4 track mag. I see the instructions about 70mm 6 track. Will there be a problem running 35mm 4 track with a CP500?
Thanks for your help.

Don

Posted by Mark Gulbrandsen (Member # 72) on 04-25-2009, 01:40 PM:

Sure it'll work but you'll have to do the surround switching/filtering in the MPU for sure. Just run the MPU outputs into the L,C,R,S inputs(DB connector) of the 500 and build a special format to rurn off the NR(if necessary). Just like feeding in a DTS or DA-20.

I don't know if it's actually worth the effort to be honest... I owned alot of 1950's/60's 35mm MAG prints including one of "Music Man" over the years and none of them were the least bit impressive. Not till the very end of 35mm mag(wasn't it one of the Barbera Streisand's movies) was the sound at all decent.

I have a brand new Teccon 4 track head for a reasonable price if anyone is interested in it. I believe it was for a JJ but it could be adapted pretty easily to other machines.

Mark

Posted by Steve Guttag (Member # 268) on 04-25-2009, 02:04 PM:

The CP500 has several 4-track mag canned formats. I'm pretty sure format 23 (NR) is one of them...IF you have a CP500/70 in order to get the 4 channels of "A-type" noise reduction.

Mark is right, any surround switching will need to be done by the MPU or other filtering.

Note too, the CP500 is looking for 388mV from its "Mag Input" like the CP65...stupid as the 300mV standard was already there.

As to the sound of 35mm 4-track...I've seen a great many set up poorly...well done it is quite impressive as compared to its mono-optical counterpart. With NR, it is definitely superior to anything SVA ever had.

Most people don't realize how much better 16mm Mag is over 16mm optical...it is pretty night and day there too.

Generally, what I find with many that try to play 4-track in modern theatres with X-curve EQs are very over-bright sounding tracks. If you apply suitable filtering to impose the academy curve onto the output of the preamps, before hitting the cinema processor (and presumming not using NR, of course)...you have a very pleasing sounding track that, despite the roll-offs imposed by the aforementioned filters, will be full of highs and lows.

Steve

Posted by Don Furr (Member # 1469) on 04-25-2009, 02:28 PM:

Thanks Mark and Steve for your help. I'm using the Dolby MPU-1 (with the surround switching card) now so I assume it will work equally well with the CP-500.

Posted by Steve Guttag (Member # 268) on 04-25-2009, 03:48 PM:

Yep...it will work...particularly if you have the Cat 92Cs to get the gain.

Note, the Cat 93 was a so-so switch card...while it did the switching just fine...it doesn't really kill the 12KHz tone...just knocks it down a peg. That tone should really be nailed with a notch filter (and I mean like 60dB or more) and on top of that, put a LPF at around 8KHz...at least 2nd order...it will knock down the hiss and the tone a bit more. With those filters...one almost never needs to switch the track on/off anymore!

Steve

Posted by Don Furr (Member # 1469) on 04-25-2009, 04:14 PM:

Thanks Steve...that's good to know.

Posted by John Walsh (Member # 168) on 04-25-2009, 05:44 PM:

Off topic, but ... how bad really was the mag surround track on 35mm? It doesn't seem that much bigger than the screen channels. Or was the idea that the screen channels would generally have something going on all the time to bury any noise, while the surrounds would have extended periods of no audio?

Posted by Mark Gulbrandsen (Member # 72) on 04-25-2009, 05:59 PM:

Early stuff is not much better than AM radio John... Because of the X curve and thats about all those early heads(and RCA speakers)could do. It's possible with a Teccon head and a nice Dolby or Teccon head end system that response with pink noise and so on to go out to 10 to 12 khz consistantly.

Mark

Posted by Steve Guttag (Member # 268) on 04-25-2009, 06:42 PM:

Actually, the response from 4-track from a modern system can easily go out to 16KHz...I've set up enough recently to know.

For early systems...it is actually much better than Mark states. The prints were mixed to the theatres of the day since they didn't have much in the way of "sound warping" circuits. As such, when they are played back on modern systems...they are very strident. They also sound thin on a modern system. However, when played back on a system of the era in a theatre of the era, they actually are dramatically better than optical sound. There is a lot of pre-emphasis clearly put into the mixes and due to the boominess of the theatres of that era...not as much bass.

Seriously...if you put an academy filter on one of those tracks before you play it back in a modern theatre...they are really quite good. They don't have the bass of a modern track, for sure but dialog is every bit as easy to understand (maybe more so with the way folks mix today) and they panned the dialog around back then...which for me is a superior method than mere mono dialog...very distracting.

Steve

Posted by Louis Bornwasser (Member # 3063) on 04-25-2009, 08:49 PM:

You will find not much above 7k on older prints without nr. I concur that 16-20k was possible. Unfortunately there was not much hf on mag better than optical. (5db down at 5k for optical; 7db down at 7k for magnetic) It was thought that hf was "bad" and so was just not mixed.

I "wide banded" an old Ampex system for "Ryan's Daughter." The film sounded exactly the same, but the hiss was high fidelity. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 04-26-2009, 12:52 AM:

quote: Mark Gulbrandsen
Not till the very end of 35mm mag(wasn't it one of the Barbera Streisand's movies)

The film was "Yentyl" (not sure I spelled that right) I had to do a few mag tune-ups when I was with RCA Service for that film.

quote: Mark Gulbrandsen
I have a brand new Teccon 4 track head for a reasonable price if anyone is interested in it.

Mark, you got any 6-track 70mm for Simplex or Century available? Shoot me a PM or phone call if you do. [Big Grin]

Posted by Michael Schaffer (Member # 1204) on 04-26-2009, 12:57 AM:

So Mark G. turns out to be a closet Streisand fan. Somehow, I am not surprised...but did we really have to find out in this way?

Posted by Sam D. Chavez (Member # 1841) on 04-26-2009, 02:49 AM:

Spot on Michael! I was just thinking the same thing as I was listening to Ella/Louis Armstrong "Autumn in New York" recording looking at my tulips.

Posted by Demetris Thoupis (Member # 833) on 04-26-2009, 04:45 AM:

Sam I didn't know you were a flower man!

Posted by Sam D. Chavez (Member # 1841) on 04-26-2009, 10:49 AM:

It was too good to pass up.

Posted by Mark Gulbrandsen (Member # 72) on 04-27-2009, 03:42 PM:

No, Never could stand ole Bananna Nose herself! Now I am surprised at Sam... Flowers???? But I guess as we all get older we tend to watch the flowers grow.

Posted by Tony Bandiera Jr (Member # 2365) on 04-27-2009, 04:04 PM:

LOL I had the honor of visiting Sam at his home recently (ok last November) and he has a wonderful garden. [Big Grin]

Posted by Don Furr (Member # 1469) on 05-01-2009, 01:39 PM:

One more question.....is the data cable on the Cat 700 the exact same as the Cat 701? The CP500 I'm receiving was using the Cat 700. My reader is a 701.

Thanks....

Posted by Steve Guttag (Member # 268) on 05-01-2009, 05:37 PM:

Yep...the reader cable has been the same since the Cat 699 days, actually.

So have no fear...and if you need more cables...we have them or can custom make any length.

Posted by Don Furr (Member # 1469) on 05-01-2009, 06:34 PM:

Thanks Steve!!!

Posted by Don Furr (Member # 1469) on 05-03-2009, 08:32 AM:

Another question I need an answer to. Will I need the Cat 685 card to run the 4 track format?

Posted by Louis Bornwasser (Member # 3063) on 05-03-2009, 09:52 AM:

Easy answer: Yes. Louis

Posted by Don Furr (Member # 1469) on 05-03-2009, 12:51 PM:

Thanks Louis....

Posted by Don Furr (Member # 1469) on 05-09-2009, 09:30 AM:

I have only one remaining problem with my CP500/mag project. The manual calls for the Center channel to tied to Pin #20 on the 6 Channel Input Connector. Problem is there is no signal coming through the 500 on that pin. All the other channels are there but NO Center. Any ideas? This is using Format 11 and I have verified that there IS a signal on the Center channel.

Thanks

Posted by Phil Hill (Member # 371) on 05-09-2009, 11:23 AM:

I think the center channel is being lost at the NR section because only the left and right channels are being passed/handled with the single Cat 222A.

To playback 4-track mag, you would need an additional Cat 222A and the Cat 669 Backplane Adapter Card.

Another thought is to use a pair of external NR units like the Cat 363.

Posted by Don Furr (Member # 1469) on 05-10-2009, 08:26 AM:

I think you've got the right answer Phil. Center and Surround required another 222 SR/A card. Thanks for you help.

Don

Posted by Gordon McLeod (Member # 33) on 05-10-2009, 09:22 AM:

Do you have the cat 669?

Posted by Don Furr (Member # 1469) on 05-10-2009, 09:26 AM:

No Gordy I don't. I've posted on the forums to see if I can find one.

Don

Posted by Tony Bandiera Jr (Member # 2365) on 05-11-2009, 04:05 PM:

Don, Get the info on the 669 and 222SR/A and then check out the pricing on the 363's with CAT 300's I have for sale in the equipment forum..see page 4, the CAT 300 FS listing.

I think it would be cheaper and better for you to go with the 363's, 300's and go into your six channel external input routing the tracks to the appropriate points. The 300's will give better performance than the 222SR/A anyway.

The 363's are fully adjustable for input and output levels.

Posted by Gordon McLeod (Member # 33) on 05-11-2009, 06:33 PM:

The 6 channel external input should not require any NR cards only the standard cat 685 should be needed and treat it as if it was a DTS player

Posted by Phil Hill (Member # 371) on 05-11-2009, 07:28 PM:

quote: Gordon McLeod
The 6 channel external input should not require any NR cards only the standard cat 685 should be needed and treat it as if it was a DTS player

Only if using external NR like the Cat 363.

Posted by Gordon McLeod (Member # 33) on 05-11-2009, 07:39 PM:

For 4 track mag you typically don't need Noise Reduction as it was rarely used on 35mm mag prints

Posted by Louis Bornwasser (Member # 3063) on 05-11-2009, 10:12 PM:

Gordon is right, unless you need NR. Louis

Posted by Don Furr (Member # 1469) on 05-12-2009, 09:59 AM:

I believe I now have my issues resolved.
I'm sending the 4 track mag through Format 11 in the CP500 which bypasses NR and EQ just like it was a DTS unit. Seems to be working great. This was after I found I had the Center channel wire in the wrong position on the 6-track external plug!!! I'm feeling sorta stupid right now.
Thanks for all of the folks who offered there ideas and help.

Posted by Louis Bornwasser (Member # 3063) on 05-12-2009, 10:43 AM:

Don: notice that you would have needed 2-222 cards, not another 222-sra card. This gives you 2 channels of sr and 6 possible channels of A nr. Louis

Posted by Frank Angel (Member # 248) on 05-12-2009, 11:14 AM:

Congrats, Don. Your efforts will be well rewarded the first time you play a 4trk mag feature. Now you will be able to see for yourself how spectacular 35mm mag can sound, even on the earlier stuff; listen to a few films and it will put to rest Mark G.s highly questionable statement that 35mm mag is not much better than AM radio(?!) I don't know what he was listening on, but not to be impressed with mag after having to endure listening to mono optical all those years means something had to be amiss with his playback system.

I have mag prints of very early titles like CAROUSEL and THE KING AND I and they sound nearly as good the DVD transfers. I have a few reels of CIMMERON (circa 1960), rejected because of over modulation which caused very mild distortion (analog distortion -- actually quite listenable compaired to the fingernails-scraping-on-a-blackboard digital distortion). And even those reels, distortion and all, simply sound great -- the recording engineer was the very accomplished Franklin Milton (UNSINKABLE MOLLY BROWN, ICE STATION ZEBRA, MUTINY ON THE BOUNTY, HOW THE WEST WAS WON), no slouch, he. The Franz Waxman score with the Roger Wagner Chorale has superb spacial depth with beautiful, delicate highs, bearing out what Steve already pointed out -- 35mm mag is quite capable of robust bottom and top end.

True, I find that it's best to tweak the eq for each film you play to get the most pleasing sound in your particular room -- not much was standarized back then ala Ray Dolby referencing, so there can be quite a difference between mixes. But unlike Mark who seems to only be impressed with things digital, I think you will be very quite satisfied with what 35mm mag will deliver.

PS -- anyone who questions whether or not 35mm mag can consistantly get out to 12hz only need listen to the damn 12khz trigger tone on the surroundtrack. If the recording engineer recorded high end in his mix, the system will play it back.

Posted by Sam D. Chavez (Member # 1841) on 05-12-2009, 12:18 PM:

It's always amazing to hear mag tracks. I did a lot of 70mm setups in the '70's and 80's and even without NR they sound amazingly good. This despite worn, low quality and misaligned (both for height and azimuth) heads, the tracks just want to sound good.

35mm is not quite as good, more noise, older tracks, warped film stock, etc., but sometimes it can still do amazingly well.

Posted by Louis Bornwasser (Member # 3063) on 05-12-2009, 03:57 PM:

35mm-4 tr mag: "poor man't 70mm"

Instead of picture and track, I once had my premieres printed on Fox hole film, striped and sounded mono on all 4 channels. I could fly in with one penthouse and a Dolby MPU and go: the operators were relieved that picture & track were not needed. (I know, I'm a chicken!) Louis

Posted by John Hawkinson (Member # 1135) on 05-12-2009, 05:47 PM:

Do I read Phil's chart correctly as saying the CP500 does NR (SR-type?) on non-sync inputs? Is that an option or something [what's it for?].

--jhawk

Posted by Steve Guttag (Member # 268) on 05-12-2009, 07:19 PM:

It is certainly possible though dubbers would be a potential source. Note, however, one should use the CP500/300 for such things as the Cat 222SR/A has too many limitations.

Steve