This is topic Robo Sound bug with CP650 in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.


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Posted by Eric Robinson (Member # 2966) on 05-26-2012, 09:44 AM:
 
I heard mention of the CP650 exhibiting "Robo Sound" when processing an AES input signal. Is there a thread here that addresses this? I would like to know more about it and how it may or may not have been patched by Dolby.
 

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Posted by Brad Miller (Member # 2) on 05-26-2012, 10:55 PM:
 
This is exclusive to running the audio from a server into a CP650 digitally (meaning not via the "dts input/format 11").

It happens. There is something on the cat790 that causes the issue. Dolby does not yet have a fix. Avoid this route. The only fix is to reboot the processor.

Unlike Steve's experiences, I can confirm it does happen in the middle of a movie as well as upon switching to the digital input.
 

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Posted by Eric Robinson (Member # 2966) on 05-26-2012, 11:58 PM:
 
Avoiding feeding digital AES straight from the server to the CP650 AES decoding input seems only possible if you decode the digital from the server with a DA converter and then input it into the CP650 analog in True?
 

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Posted by Steve Guttag (Member # 268) on 05-27-2012, 06:05 AM:
 
I'll defer to Brad on this one...he was the one that told me it could (would) happen. Thus far, it has only happened on one of my CP650s. We ended up changing the CAT 790 board and the problem has not returned. However, it has spooked me enough to avoid wanting to use the CAT 790 as my DCinema input.

The problem is, if one has as combination film/DCinema booth, the CP650 is a VERY attractive unit since the theatre often already has the CP650 and possibly already has the CAT 790. If the theatre was wired for Surround-EX (as most mine were after it came out because it just didn't cost more to do it that way) then Surround 7.1 was/is essentially free too.

I'm still thinking that if one were to interrupt the pair-1 of the AES feed (e.g. have a relay in-line) that it would resync. However, my exposure to the problem has been minimal and I don't have any current systems exhibiting the problem to experiment with (the one I had was a new CAT 790...still in warranty so it was changed immediately).
 

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Posted by Joe Elliott (Member # 4006) on 05-27-2012, 07:46 AM:
 
I assume this is different from what we used to call "tin can sound" which was when the cp650 would change inputs, the sound did kind of sound robotic, but to me it sounded like a radio playing inside of a tin can. We had 2 650's that would do that very infrequently. One had a 790 card, one did not (the other was a film system). The way to get rid of it, was to switch to a different style of input. If it was in NS, switch to format 10 and back, if you switched to another analog format, it would not stop. If it was an analog input, switch to digital, if it was a digital format, switch to analog. We had 10 650 units, and only the two ever did it.

I wonder if the two problems could be related. Bad revision of motherboard perhaps? Does it seem to only happen on certain units?
 

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Posted by Brad Miller (Member # 2) on 05-27-2012, 10:54 AM:
 
I've not seen a pattern, but it happens much too frequently for me to recommend anyone use the digital input on a 650. (Keep in mind my sample of 650s is significantly greater than Steve's, and also many times a manager may simply reboot the processor and never let their tech know.)

The DMA8, 750, ECI-60, and all other D-A converters do not suffer this issue. So long as the format 11 analog input is used on the 650, it won't happen.
 

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Posted by Marco Giustini (Member # 4544) on 05-27-2012, 11:33 AM:
 
Brad, is it just my impression or the 6ch input of the CP650 is much more noisy than, say, a CP750?
 

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Posted by Manny Knowles (Member # 1171) on 05-30-2012, 08:25 AM:
 
Yeah, I've had the Robo-Sound here once or twice.

Unfortunately all of my DMA8 inputs are occupied with other devices.

Originally, our DCI sound went to the DMA8 via an AES router, but that seemed to cause clocking errors (which caused "snits" in the surrounds). So, given my options, I'd rather have Robo-Sound once a year than to have clocking errors 100% of the time.
 

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Posted by Joe Redifer (Member # 3) on 05-30-2012, 05:04 PM:
 
Ug. Rebooting a CP650 takes significantly longer than rebooting a computer (or maybe even assembling one). It's something Dolby kind of might want to look at. Or perhaps they'll just leave it be, hoping everyone will buy new CP750s. But when the 750 develops a bug, don't hope for a fix on that one, either. Instead you'll have to get a new 850.

Dolby: hard at work on your side!
 

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Posted by Jerome Holmes (Member # 5013) on 05-30-2012, 08:59 PM:
 
So when saying robo sound, are we still talking distinguishable dialog, just robotic sounding? Just so I'm clear, I'm asking because one of my screens here has been giving off what almost sounds like white noise. We tried rebooting the 650, which would sometimes make the issue disappear...
 

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Posted by John Thomas (Member # 6509) on 05-30-2012, 09:42 PM:
 
I've heard it happen on only one surround channel, but also on center. It sounds like the audio has been "bit-crunched" or "decimated." Sort of like at a very low bit-rate, but not exactly. Certainly distinguishable, but by no means listenable.
 

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Posted by Tony Bandiera Jr (Member # 2365) on 06-18-2012, 10:03 PM:
 
So far, in the few screening rooms I have dealt with (one with a setup that has been in a home for over three years) haven't had this happen yet.

I hope it doesn't crop up at all because all the rooms I have done so far have to use the external 6ch input and I really don't want to go back and add a DMA8 (and rewrite the AMX code, and install extra serial cards for the AMX too.)

Fingers and toes crossed.....
 

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Posted by Tony Bandiera Jr (Member # 2365) on 06-20-2012, 06:35 PM:
 
A thought on this issue:

What version(s) of the software does it crop up with?

With the other issue I am having with my CP650 at UCI I am wondering if this is another possible software bug.

Brad, have you considered "downdating" the software to 2.3.4.4 to see if the issue goes away?

Seems like a software issue since it only affects some processors and not others, and that a reboot cures it.
 

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Posted by Manny Knowles (Member # 1171) on 06-21-2012, 11:27 AM:
 
I've experienced this with CP650 v 2.3.6.6
 

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Posted by Tony Bandiera Jr (Member # 2365) on 06-21-2012, 07:07 PM:
 

quote: Manny Knowles

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I've experienced this with CP650 v 2.3.6.6

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quote: Steve Guttag

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Robo sound is NOT software dependent. It is Cat 790 dependent...if you have it, only changing the Cat 790 will cure it (if the one you get is a "good one").

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That isn't the current story from Dolby. Now they are blaming software.
 

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Posted by Steve Guttag (Member # 268) on 06-22-2012, 12:30 PM:
 
Dolby doesn't seem to blame anything...they almost seem to ignore it. If it was software (and they thought it was) they would revise the software (a relatively minor thing to do, resource wise).
 

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Posted by Tony Bandiera Jr (Member # 2365) on 06-24-2012, 12:41 PM:
 
Brad, what versions have you seen this happen on? And if you can say so publically, who at Dolby told you that it is software?

Steve, sadly you are right, Dolby just doesn't seem to care about anything anymore, their support has diminished in quality a lot as of late. I can remember when if you had a problem with any processor, not only could they narrow it down over the phone but they would next-day ship replacement cards to get you running again...and if that didn't work they'd send a replacement processor. (Now I have heard that support for the DSS-200 is still at that level....for now.)

My changeover issue......well no one at Dolby seemed to have any clue as to what is wrong, though I do give credit to Norm Cerda for trying, but when the boards he sent didn't work they ran out of ideas and seemed to lose interest in solving the problem. No one I have contacted there even knows who wrote the software to try and see if there is a bug in this latest version. So I am left to keep trying "downdates" to hopefully fix the problem.

And I am now hoping I don't end up with the robo sound bug....


 

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Posted by Steve Guttag (Member # 268) on 06-24-2012, 12:54 PM:
 
Tony,

I had the issue with a CP650 running 2.3.6.6 on a NEW CAT 790...Dolby immediately swapped the CAT 790 and the problem has not returned. If it was software, this would seem less likely. Dolby was very proactive on it.

I had a client that had the issue on 2.3.5.3 (before the CP750 came out).

I must admit, my personal encounter with it has been very small (and quickly addressed). We have several CP650s out there running combo DCinema and Film and only one unit that I personally service that it showed up on (again, right after we put in the CAT 790).
 

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Posted by Brad Miller (Member # 2) on 06-24-2012, 01:00 PM:
 
Tony, anything above 2.3.4.4 for certain has done it. Dolby has been working hard to resolve it. Initially it appeared the culprit was the board, but as I understand it now they are looking into the software. Intermittent things, particularly rare ones, are extremely difficult to track down as I'm sure you are aware.
 

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Posted by Tony Bandiera Jr (Member # 2365) on 06-24-2012, 01:13 PM:
 
Brad and Steve thank you for your quick answers.

Let's hope Dolby can figure it out now.

And yeah, intermittent problems are always a pain to solve.....
 

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Posted by Steve Guttag (Member # 268) on 06-24-2012, 05:56 PM:
 
My bet is that they are looking for a software solution to a hardware problem...that is...if it determines that it is in robomode...resync to get out of robomode.
 

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Posted by Manny Knowles (Member # 1171) on 06-24-2012, 06:25 PM:
 
AKA...cheaper than recalling Cat. 790 cards -- follow the money!
 

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Posted by Steve Guttag (Member # 268) on 06-24-2012, 10:59 PM:
 
Recall nothing...it would likely require a redesign. I'm sure they don't want to put engineering time on a product that primarily supports a dying format.
 

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Posted by System Notices (Member # 2357) on 09-13-2013, 04:17 PM:
 

It has been 445 days since the last post.

 

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Posted by Harold Hallikainen (Member # 5405) on 09-13-2013, 04:17 PM:
 
Does anyone have a consistent method of reproducing robosound? If so, I'd like to send out a new piece of hardware to put in the AES/EBU line to see if it solves the problem.

THANKS!

Harold
 

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Posted by Steve Guttag (Member # 268) on 09-13-2013, 06:19 PM:
 
Not that I'm aware. Since it only syncs on channels 1/2...I was debating if interrupting that line until the source is needed would cause it to always re-sync itself.
 

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Posted by Harold Hallikainen (Member # 5405) on 09-13-2013, 07:49 PM:
 
Thanks! We have a little 8 channel sample rate converter that I was hoping would solve the issue. If anyone can reproduce the issue, I'd like to see if this fixes it.

THANKS!

Harold
 

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Posted by Steve Guttag (Member # 268) on 09-14-2013, 06:50 AM:
 
Dolby does/is working on a software fix that I've tried...it seems to work or work to some great degree. Where I've tried it...I don't recall getting any complaints.
 

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Posted by Brad Miller (Member # 2) on 04-08-2014, 09:51 PM:
 

 

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Posted by Pete Naples (Member # 761) on 04-11-2014, 04:20 PM:
 
I've tried it too Steve, it still happens.
 

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Posted by Steve Guttag (Member # 268) on 04-11-2014, 07:25 PM:
 
Yeah, but how often?
 

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Posted by Ken Lackner (Member # 1002) on 07-16-2014, 01:41 PM:
 
It seems I may have witnessed my first occurrence of CP650 Robosound today. Thing is, I'm not certain, and wish to seek clarification. I gather from reading about it on this forum, that it when the issue occurs, audio sounds "choppy," as if you are talking into a fan. (Just like the pic Brad posted above.) That's not really what happened. It sounded more like a staticky distortion. But I do know that power cycling the CP650 cured it. Was this, in fact, "Robosound?" Are there different manifestations of it?

Steve, what software version are you running?
 

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Posted by System Notices (Member # 2357) on 10-30-2016, 02:13 PM:
 

It has been 837 days since the last post.

 

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Posted by Manny Knowles (Member # 1171) on 10-30-2016, 02:13 PM:
 
On 6/21/12, I wrote:

quote: Manny Knowles

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I haven't had robo-sound in over a year -- i ain't about to change a thing! -- unless it happens again...

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