Film-Tech Forum ARCHIVE: CP55 vs. CP65

my profile | my password | search | faq & rules | forum home

»	Film-Tech Forum ARCHIVE » Operations » Film Handlers' Forum » CP55 vs. CP65 (Page 2)

This topic comprises 2 pages: 1 2

Author

Topic: CP55 vs. CP65

Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 11-30-2007 05:41 PM

I don't know that the 650 has "Real SR". It is a digital representation of the real SR on the 280 and 300 series which were analog cards. We don't know what model Dolby used as the golden example, but the task of getting it perfect to the original is daunting. IMO, real SR is analog 280 or 300 series.

Someone should ask Ray Dolby his opinion.

[ 11-30-2007, 09:12 PM: Message edited by: Sam D. Chavez ]

| IP: Logged

Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 11-30-2007 09:22 PM

And would he give a answer [Big Grin]

| IP: Logged

Lyle Romer
Phenomenal Film Handler

Posts: 1400
From: Davie, FL, USA
Registered: May 2002

posted 11-30-2007 09:28 PM

At 74 years old I'm not sure if Ray's ears are still sharp enough to tell the difference. If they are then I want to know what diet he eats and what vitamins he takes.

| IP: Logged

Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 11-30-2007 10:01 PM

Just to drive the point home....the Cat 222"SR"/A has much more wrong with it than mistracking at the high end. Its frequency response is notably wrong and its dynamics are wrong and many frequencies and at varying levels. It has SR like characteristics but so does every other SR knock off to varying degrees...some do it better than others. SR is a complicated system that has a self-adjusting transfer function. It is essential that the encode/decode are identical, above and beyond any other noise/harmonic concerns.

I've never had a problem with either Cat 280s or the 300 series not sounding natural with a well set up system...I can't make that same claim from most if not all of the others. Panastereo does really well as does the CP650's digital clone of the SR. Nothing on either has ever jumped out and and waved a flag saying it was mistracking on the occasions that I have heard them running in SR. I've also found that optical stereo and its inherent random noise floor will really show off bad SR decoding more so than say a Mag track that tends to have steady-state noise floors.

And the CP65 is by far the better choice over the CP55...way more flexible and still very usable in today's cinema. The CP55 just needs too much money thrown at it to bring it up to psudo-CP65 capabilities. Now, if the CP55 is fully updated, that is another story...then your functionality is much closer.

| IP: Logged

Sebastian Binz
Film Handler

Posts: 32
From: Cologne, Germany
Registered: Nov 2007

posted 12-01-2007 05:26 AM

Hi again,
it seems like the CP65 is already sold and the only option left is the cp55.
It is updated to SR though, containing the crappy 222 SR/A card as well as a Cat 441.
It comes wired within a rack with DA20 and DTS6, so I suppose I will stick to the deal. Maybe some time in the future I will throw out the processor and put something better in that place, but with our house from 1938 and the poor accoustics I guess we are within a region that no one will be able to tell the difference between real SR and fake. Plus, the price of the rack is within a range that some other companies were asking just for the DA20.

Theres just one thing: The rack comes out of a cinema that was running a platter on a FP30D. Now we will put it into our changeover house. What kind of modifications are necessary to get the processors running with two projectors?

(I know that we will have to put in a motor switch, although I'm not quite sure how we are gonna accomplish that for now. Maybe we'll just have a simple switch for the projectionist to throw at the beginning. Are there any drawings or something how that is done elsewhere?)

best rgrds

Sebastian Binz

[ 12-01-2007, 09:12 AM: Message edited by: Sebastian Binz ]

| IP: Logged

Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 12-01-2007 08:53 AM

Since the CP55 has the Cat 441 and the 222SR/A...you have most of the functionality of most CP65s...it isn't a bad deal. Is the SR as good as it should be? No but it is better than nothing.

As for 2-projector...not to worry...most every cinema processor is 2-projector capable and the CP55 is no exception (nor is the DA20). A simple held contact closure is all that is needed to send the CP55 to projector #2. If using toggle switches for sound changeovers, then wire them up a 3-way switch to the "C/O" terminal. If you want something more automatic....in the States it is most common to use a latching relay like the P&B "KB" or "KBP" series (still available but EXPENSIVE). One is hooked up to the changover coil (open and close as the relay is a dual coil relay) so when the changeovers energize, it will follow it.

If you have Kinoton or like changeover, most people use a relay or use a provided contact that follows when projector #2's C/O douser is open (it is common in non-US machines for the c/o douser to funciton as the fire douser too and thus is held open by its own electronics and closes if the machine is turned off). For my Kinoton installations, I made a PC board with relays on it that will monitor each projector's motor and changeover functions so that the cinema processor is only told to look at a machine that is running and its dowser is open.

Steve

| IP: Logged

Brian Guckian
Jedi Master Film Handler

Posts: 594
From: Dublin, Ireland
Registered: Apr 2003

posted 12-02-2007 10:17 AM

How about:

a) Selling the CP55 on again to partially fund a CP65;

b) Raising more funds to buy a CP65 and if necessary Cat. 300 / 350 cards, make modest improvements to your room acoustics and hire a local projection engineer to install the new equipment ?

Just some suggestions...consider doing it for your Audience and have it that they will indeed be able to tell the difference in the quality of the SR, etc.

| IP: Logged

Martin Brooks
Jedi Master Film Handler

Posts: 900
From: Forest Hills, NY, USA
Registered: May 2002

posted 12-02-2007 10:47 AM

quote: Sam D. Chavez
Someone should ask Ray Dolby his opinion.

I believe the erstwhile Mr. Dolby has been quoted as saying that he didn't even think Dolby C or S (in the consumer world) was necessary. He says it was produced for marketing reasons. I'd bet he thinks that SR was not necessary beyond A, although that's obviously a different question than as to whether analog SR or digitally represented SR is better.

| IP: Logged

Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003

posted 12-02-2007 11:27 AM

Digital representation of SR can not be better than the Analog original, only an aproximation. It's how close one can get that is at issue.

Ray Dolby was late in moving to Digital as he was not done with SR development either in technical or emotional terms.

It was only the introduction of CDS and the legs it showed that got the company fully engaged. The fact that CDS screwed the pooch gave Dolby some breathing room.

| IP: Logged

Paul Gordon
Jedi Master Film Handler

Posts: 580
From: Ottawa, Ontario, Canada
Registered: Aug 2005

posted 12-02-2007 11:35 AM

Since you've got a CP-55 and its all wired up, use it. In the mean time look for a SRA5 or Ultra Stereo SRM-10 frame that can hold Cat 280T cards. You can even buy Cat 280 cards and cut the jumper so they act like Cat 280T. This stuff is around and more and more of it will come up with Digital Cinema taking over.

| IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1 2

Printer-friendly view of this topic

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.