Film-Tech Forum ARCHIVE: no sound out from ims3000 to cp750 source from apple tv

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Posted by Adnan Hijazi (Member # 10814) on 04-03-2019, 03:40 AM:

Hi All,

I have IMS3000 installed on Christie i have problem with sound if the source from alternative like apple TV .

first i will describe the connection and then solution i was try.

the connection between IMS3000 to dolby audio proccessor CP750 using Shielded cat6 from AES 1-8 & AES 9-16 to 4x AES IN on CP750 using RJ-45 to DP25 Adapter .

Information for devices it was installed on location :
(The amplifier model WSS 1400 ) & The sound system is 5.1 & Speaker model JBL & Audio monitor is crown DSi-8M .

The Problem :

IF the source from DCP there no problem with sound it's out well on Digital 1 in CP750.
But if the source From alternative like Apple TV using HDMI IN on IMS3000 by make Live Show from WebUI the picture out to screen well without problem but the sound not out to cp750, but on WebUI the sound meter its moving but on cp750 screen the sound meter not moving and no sound out from Digital 1 or another source else if i try use Gefen HDMI switcher i get the audio out from it using SPDIF output to CP750 on Digital 2 input there sound out without any problem .

Solution i was try :

Change Cat6 cable and same problem (if the problem from cable the sound from DCP should not out, but the sound from DCP out without any problem. ) but i was to try this solution.

change HDMI cable same problem

remove cat6 cable from AES 9-16 on IMS3000 and try same problem no sound from HDMI source.

try another source not apple TV i try Samsung Blu-ray player same problem no sound out from speakers .

i try run Macro and same problem picture out to screen but no sound out to speaker.

So some one tell me to make Routing with Dolby atmos Destinger because the IMS3000 the default output is AES67 so need to routing it to 5.1 this solution i not try it .
( i don't know if this solution correct or not and i don't know how make it on DAD software )

Another one said : need Dolby Software Feature Activation Licence to fix this problem

So did IMS3000 out the sound to speakers from HDMI source ?
any solution for my problem ?

Thanks
Best Regards

Posted by Leo Enticknap (Member # 534) on 04-03-2019, 09:13 AM:

The most likely explanation seems to me that you need to make up a DAD file that routes the alternative content channels correctly.

The problem clearly is not that the IMS3000 cannot decode the HDMI audio, because you are seeing its signal on the IMS's VU meter display. That also rules out an EDID or HDCP issue. It also isn't your RJ45 to DP25 adapter, because you're hearing the DCP sound in the auditorium (presumably with the right channels in the right places).

I have got HDMI audio working OK on an IMS3000 on at least two installs that I can recall, but both were Atmos installs, with a full DAD file being worked up for them.

My guess is that the AES outputs from the IMS have the regular DCP channels routed to them by default (i.e. what will happens if you don't upload a DAD file into it at all), but not the HDMI channels, and that you need to "hard route" these channels in a DAD configuration. However, the last time I set up a 3000 from scratch for alternative content playback was last September, so this guess comes with no guarantees!

However, one potential gotcha is that the IMS3000's HDMI input can deal with LPCM and Dolby-encoded audio only - no DTS. So your alternative content sources should be forced to LPCM and/or Dolby output (not bitstream). If they start to output DTS for any reason, your VU meters will go blank and there will be no sound. But, to reiterate, that doesn't appear to be the problem in this case, because you write that you can see the input signal on the web UI.

Posted by Dave Macaulay (Member # 813) on 04-03-2019, 10:01 AM:

I suggest you call or email Dolby support with your question. You may not get a quick reply today as they are all probably gone to Cinemacon for a few days.
It's probably something simple, Leo is probably right but it seems a bit much to need to create a DAD file just to get HDMI audio working.

Posted by Carsten Kurz (Member # 5396) on 04-03-2019, 10:05 AM:

Try playing an audio only source, make sure the audio setup of the AppleTV is set to LPCM. That could give a first hint towards what is going on.

- Carsten

Posted by Dave Macaulay (Member # 813) on 04-03-2019, 01:47 PM:

I'm not familiar with the IMS3000 (yet) but for audio processors the channel level display is generally signal level, not output level. Dolby processors work this way, the bars dance with fader at zero. So there's a signal path problem either muting the output, or the signal isn't routed to the outputs... for a reason I do not know.