Film-Tech Forum ARCHIVE: Sound processor analog inputs?

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Posted by Harold Hallikainen (Member # 5405) on 08-26-2015, 03:56 PM:

How frequently do you end up using the 8 channel analog input on a sound processor? If you use it, what do you typically drive it with?

What about pin out? We currently use a THX pin out for analog. However, there's now AES 59-2012, which is a standard pin out for both analog and digital audio on a DB25. This is the same pin out used for AES/EBU on a fair amount of equipment (USL JS-100, etc.).

Note that the CP850 moved away from the THX pin out to AES 59-2012 for the analog outputs.

Thanks!

Harold

Posted by Scott Norwood (Member # 30) on 08-26-2015, 04:09 PM:

If you are talking about a "normal" cinema, it is probably never used.

This becomes important, though, for special venues. I would like to see at least two analog 8-channel intputs--one for a film processor (assuming that the box in question has no support for film) and one for a Blu-Ray player (or similar) with discrete outputs. A third might be nice for a DMA8 or something else, but that can be dealt with as needed.

Assuming a digital processor, is there any reason why the pinout cannot be configured in software?

(Is the AES pinout the same as the Tascam one, or do we now have a third DB25 to multichannel analog configuration?)

Posted by Harold Hallikainen (Member # 5405) on 08-26-2015, 04:20 PM:

Thanks for the comments! The AES 59-2012 is the same as the Tascam pin out.

Because analog inputs need to drive analog circuitry, a software configurable pin out would be quite expensive (a 25x25 analog matrix switch).

Again, thanks for the comments! Any more on use of the analog input? I note that the CP750 has it, but the CP850 does not. It's a fairly high cost item to manufacture. But, it IS nice to handle bitstream decoding in a Blu Ray player instead of having to incorporate it in the cinema sound processor. Decoder license fees go down with volume, and the volume on Blu Ray players is much higher than the volume on cinema sound processors.

Harold

Posted by Steve Moore (Member # 4753) on 08-26-2015, 05:32 PM:

We feed the 5.1 from our CP65 for film into the Multi in on the CP750. This input is also wired via a relay to switch so we can also feed in the analogue out from a DTS processor (which converts optical to 5.1 analogue) to get 5.1 from a bluray with DTS only sound.
It's a useful and much used input for us, especially for festivals and running 35mm about once a month.

Posted by Gordon McLeod (Member # 33) on 08-26-2015, 06:19 PM:

I still use it fairly frequently for alternate content inputs

Posted by Stephen Furley (Member # 1277) on 08-26-2015, 06:26 PM:

Apart for more typical uses, we use it all the time for the DMA8 plus, odd channels in it can be useful for other things, the centre channel for the line out from a 16 mm machine, and the left and right surround channels for the output from a mic mixer. We have no PA speakers and it's almost impossible to put mica onto the main film speakers without getting feedback, so it's sometimes useful to provide a small amount of sound reinforcement for those sitting towards the rear of the auditorium this way.

Posted by Steve Guttag (Member # 268) on 08-27-2015, 12:13 PM:

I see the multichannel analog inputs used ALL the time in all sorts of venues. Typical uses include Blu-Ray as well as most any video sources or any legacy film type equipment. Not having one is a BIG, BIG mistake.

Posted by Brad Miller (Member # 2) on 08-27-2015, 01:08 PM:

Harold, not having a 6 channel analog input is pretty much a blacklist to the product in my opinion.

Posted by Marco Giustini (Member # 4544) on 08-27-2015, 02:48 PM:

I agree, it is used pretty often. Some setup won't need it but many others will. Not having a 6ch input is a big issue.

Posted by Harold Hallikainen (Member # 5405) on 08-27-2015, 04:53 PM:

Thanks for the comments! Just checking. I'm thinking the most popular usage would be Blu Ray since you could rely on the decoder in the player.

Again, thanks for the comments!

Harold

Posted by Carsten Kurz (Member # 5396) on 08-27-2015, 05:35 PM:

We would always prefer a processor with a multichannel analog input. But, we hardly ever use it. In our case, it is fed by the CP65 for (rare) film applications.
BluRay seems obvious, but there are hardly any players with discrete analog outs on the market now. It's easy to pinpoint the Oppos as the only real deal for cinema use, but they are nearly the only ones left.

I know you have your HSW-602, but I think ANY new cinema sound processor needs a HDMI input. It would probably not need all the expensive decoding options, as there are a lot of BluRay players now that will decode to multichannel LPCM.
But clearly, a lack of bitstream decoding will always be a problem to communicate.

- Carsten

Posted by Steve Guttag (Member # 268) on 08-27-2015, 07:13 PM:

HDMI is a scary input...too easily disturbed by HDCP. What I'm surprised that Dolby never made for the CP850 is an analog 8-channel to HDMI converter. It would let the people that want/need it have a means without having to do heroics by other means without coming up with the real estate on the back of the unit and putting in all of the A-D converters.

Having a professional processor that will take any form of audio encoding on HDMI and making high-quality audio would be nice. Currently, Crestron sits alone with their HD-XSP, which would need a multi-channel analog input to use.

And contrary to Brad's 6-channel requirement, for me, now, it is 8-channel. 7.1 is so prevalent now in cinemas and more so in the home.