Film-Tech Forum ARCHIVE: CP650 issue?

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

»	Film-Tech Forum ARCHIVE » Operations » Film Handlers' Forum » CP650 issue? (Page 1)

This topic comprises 2 pages: 1 2

Author

Topic: CP650 issue?

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-28-2002 06:50 AM

Hi everyone

Yesterday a strange thing happened to one of our CP650 on a Minority report print.
Ushers called that the voices has disappeared. From the booth monitor I can heard an "echo" of the voices from all the channels, like the surrounds was connected to the LCR channels. The CP was regularly in format 10, no problems. I was going to bypass when I pushed format 5 to see if the problem was only for Digital decoding. The CP select again Format 10 (it is normal, auto digital!) and the problem was disappeared.

I don't know Cp650, I know CP500 and it has some strange problems sometimes, nothing to be warried.

Do you know if CP650 has some known problem or perhaps our unit is defective?

Ciao
Antonio

| IP: Logged

Ray Derrick
Master Film Handler

Posts: 310
From: Sydney, Australia
Registered: Sep 2001

posted 10-28-2002 07:22 AM

Antonio it may be just one of those software bugs that seem to haunt digital equipment. I have heard a similar thing on a CP500 on the movie "South Park". Every so often the centre channel would drop in level and the left and right channels would start reproducing the dialogue at the same level as the centre but slightly delayed. Very annoying. It may have been that the unit was reverting to analog but the software was sending the analog to the left and right channels whilst still playing digital from the centre (or vice versa). I didn't have the opportunity to investigate it at the time.

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

| IP: Logged

Michael Schaffer
"Where is the
Boardwalk Hotel?"

Posts: 4143
From: Boston, MA
Registered: Apr 2002

posted 10-28-2002 08:18 AM

The problem is likely to have been a software hang-up in the ProLogic Decoder. As Ray described, the decoder is responsible for the channel routing. By selecting SR, you changed the decoder input source and so reset it. Those problems are very difficult to track, as you can`t reproduce them at will.

| IP: Logged

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-28-2002 08:56 AM

Thanks for your replies.

I worked for 4 years with two CP500 and I known that sometimes something strange would happen! Was normal! Just reset the unit and go on! Like the "SW" bar dancing with no sound...

Should I think the same thing with the 650 or not? Of course the unit will be serviced if it will happen again in the same screen.

Bye
Antonio

| IP: Logged

Wes Hughes
Expert Film Handler

Posts: 175
From: Raleigh, NC, USA
Registered: Aug 2001

posted 10-28-2002 10:13 PM

I have problems similar to this on occasion with some of my 650's. They usually take the form of extremely "tinny" sound, even in non-sync. Dialogue would sometimes be totally distorted. A reboot always fixed it. A software upgrade a few months ago almost solved the problem (only happened once in the last 5 months instead of once a month before the upgrade).

| IP: Logged

Don Sneed
Master Film Handler

Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001

posted 10-29-2002 09:53 AM

I had a few of these Cp-650 lose it's memory, I had to to reinstall all the saved settings from a floppy disk I leave at the theatre after the install...two of these units work normal again after uploading the settings, one was so bad the theatre had to upload the settings every day, the memory would not keep it after turning off for the night, Lonnie at Dolby sent the new CP-650 software to install to correct the problem...all was ok after that, so there is a software issue in some of the older CP-650....

| IP: Logged

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-29-2002 11:30 AM

Don,

I knew about the memory loss of CP650. All of our CP has been upgraded when installed. I do not remember the software version right now.

Bye
Antonio

| IP: Logged

Michael Schaffer
"Where is the
Boardwalk Hotel?"

Posts: 4143
From: Boston, MA
Registered: Apr 2002

posted 10-29-2002 07:23 PM

All that is probably not Dolby`s fault. I understand they use Motorola DSP chips, is that correct? What brand of memory? It may be that some of the components which are delivered by the manufacturers in batches were faulty. That doesn`t apply to the problems which were solved by the firmware upgrade, of course.
Antonio, I checked the Field Bulletins. There is no recent one about the CP650 which describes that problem.

| IP: Logged

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-30-2002 05:45 AM

Thanks Michael for your help.

No problem with Dolby, this is the first time we had problems with our 16 CP650 installed!

Bye
Antonio

| IP: Logged

Ray Derrick
Master Film Handler

Posts: 310
From: Sydney, Australia
Registered: Sep 2001

posted 10-30-2002 06:28 AM

Michael, don't be so eagar to dismiss Dolby's blame in any malfunction of the CP650. As the guy who built the world's first serious microprocessor controlled cinema sound processor, I can assure you that 99.99999% of the time it is the software (or more correctly the "firmware") that is to blame. This is not to say that Dolby are lax or less than diligent in their attempts to produce a very high class product. The simple fact is that the DSP and microprocessor hardware from companies like Motorola is exceptionally reliable, in fact, considering the complexity of the wafer designs, remarkably reliable. Firmware hiccups WILL happen, it is just too much to ask that firmware be written perfectly every time. Be thankful that software engineers get it right MOST of the time. Given the massive potential for error in such a complex environment, that in itself is a miracle.

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

| IP: Logged

Michael Schaffer
"Where is the
Boardwalk Hotel?"

Posts: 4143
From: Boston, MA
Registered: Apr 2002

posted 10-30-2002 11:23 AM

It may be a simplistic way to think, but since I am not a sound hardware designer myself, I arrived at this conclusion simply (or simplistically) by thinking, if the problem is in the firmware, why does it seem to affect only specific units?

| IP: Logged

Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 10-30-2002 11:50 AM

If the problem is in the hardware itself, wouldn't it still be Dolby's fault for selling equipment made with substandard parts?

(Note that I basically like Dolby products and I'm not trying to single them out. Any company which knowingly sells defective equipment should have the decency to admit the problem, apologize to its customers, and replace or repair the equipment.)

| IP: Logged

Ray Derrick
Master Film Handler

Posts: 310
From: Sydney, Australia
Registered: Sep 2001

posted 10-30-2002 08:07 PM

Michael, if the same problem is occuring in more than one unit it would seem unlikely that a hardware fault is the cause. There is always the chance of a bad solder joint or faulty component on a printed circuit board, but usually faults of this type will be different for each faulty unit. In contrast, if the same problem is occurring over a number of units it suggests an error in the firmware. So why do all units not have this problem? Well you often have different versions of firmware in different units. Also bugs usually only show up under very specific circumstances, (which is why they are missed in the first place) usually when the processor is called on to do something unusual. Microprocessor and DSP processor chips are really very simple devices (only on grand scale) that either work or they don't. In my experience, any fault, however small, in such hardware will usually cause catastrophic results.

------------------
Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

| IP: Logged

Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 10-30-2002 09:03 PM

More, I believe that not all Dolby has the same card inside... There are many revision of components and perhaps a problem can be present with one particular revision...

However, the sound issue is continuing (the only one on 16 CP), so we believe that our unit is defective.

A thought: it is Minority Report (EX) on non ex screen. Can be the EX bit causing some problems?

Bye
Antonio

| IP: Logged

Steve Guttag
We forgot the crackers Gromit!!!

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

posted 11-01-2002 09:49 AM

I'm much more generalistic in my blame of things...If I am dealing with an entity (sound company) and a component inside their product fails...I don't care why it failed, I blame the company I'm dealing with. They got to choose what they used and how they implemented it...it is all on them.

One problem I'm seeing within this industry are the dabblers...those companies that built their reputation on making a particular type of product but have decided to branch out to seem like more of a one-stop-shop...the problem is, their other products don't have the same quality as their old stand-bys.

One thing I have learned over some time...don't dabble into the digital realm...Digital almost always involves software and hardware and each requires very talented people to pull it off. More often than not, I'm disappointed with the results. Furthermore, it is flakey. With digital, things either work or they don't.

BTW...my specialy was always hardware.

Steve

------------------
"Old projectionists never die, they just changeover!"

| 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.