Film-Tech Forum ARCHIVE: Dolby CP750 vs CP650

This is topic Dolby CP750 vs CP650 in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by William F Green (Member # 3192) on 08-06-2012, 07:44 AM:

Hi all, I've been offered a used CP650 (with all options installed for digital cinema sound) but as this is to be used purely with a server and no film at all (at least for the foreseeable future) I'm wondering if we should in fact opt for new CP750 which would seem to come in at around the same price.
Which is regarded as the better/more flexible processor for an all digital install?
Thanks.

Posted by Tony Bandiera Jr (Member # 2365) on 08-06-2012, 01:14 PM:

It really boils down to this, since your pricing is comparable:

Is there even the slightest chance you will need to run film now or in the future? Get the CP650.

If you are 100% and I mean totally 100% POSITIVE that you will NEVER, EVER run film again (I hope I emphasized that enough) then get the CP750 as it is a great processor and has a few features that the 650 doesn't.

Based on those conditions you won't go wrong.

Posted by William F Green (Member # 3192) on 08-06-2012, 01:29 PM:

Thanks Tony,
Well never say never. I'm certain we will never ever run any film in this venue as that's virtually a physical impossibility - the NEC will be mounted on the front of the balcony due to lack of space.
But if we had to move venue again it's not impossible that we might want to run film, but then we already have a CP45 and a CP55 so that's not a big issue I think? What sort of facilities does the 750 have that the 650 does not by the way?
Thanks.

Posted by Tony Bandiera Jr (Member # 2365) on 08-06-2012, 01:41 PM:

William, thanks for the extra info. Since you have the CP45 (which I would toss in the bin) and the CP55 then a 750 would be your best choice.

The 750 has one feature which I think is the best: It has an optical toslink input which is compatible with consumer gear for feeding audio from say a blu-ray or dvd player. It provides Dolby Digital and Dolby Pro-Logic and Pro Logic II decoding depending on the data stream coming in.

It also has 8 ch. analog audio input, (2) AES single inputs and (1) 4xAES input (For use with the server.)

It is basically like having a CP-650 and DMA-8 combo in one box.

Here's the scoop: CP 750

Posted by William F Green (Member # 3192) on 08-06-2012, 01:48 PM:

Thanks that's really useful info - I'm not that familiar with the 650 so was not sure of the extra features the 750 had in comparison. We will be running DVD & BluRay alongside DCP so will certainly bear this in mind.

Posted by Tony Bandiera Jr (Member # 2365) on 08-06-2012, 01:52 PM:

You're welcome. And another thing which may be helpful for your venue, you can buy optical Toslink switches so you can connect more than one player to that same input without having to swap optical cables.

Posted by Dave Macaulay (Member # 813) on 08-08-2012, 10:30 AM:

I think the 750 has enough extra features to make it the right choice. The 650 also has some problems with the AES digital input (occasional but nasty, and with a used unit you won't be under warranty - and you don't want to pay ~$14,000 for a new 650 I'm sure). CP750 ethernet control is pretty much effortless, the 650 version is not so simple if you want to use it (unless you use a Dolby server).
If you want to go film again: just use the CP55 for film optical, flatten or bypass the EQ, and feed it's 5.1 output into the CP750 8 channel analog input. Getting SR-D is a bit less simple but you would connect a DA20 to the CP55 just like always and still go through the 750.

Posted by William F Green (Member # 3192) on 08-14-2012, 09:14 AM:

Thanks Dave for adding to Tony's input. Yeah, I'm pretty much certain that for the foreseeable future the 750 would be the wisest choice as no 35mm is on the agenda for this venue at all. Prices here are pretty fair at the moment for a 750 and having spent a shed-load of money on just a lens the cost of the 750 seems quite modest in comparison really..
Thanks again for the opinions - it's helped me make up my mind.

Posted by William F Green (Member # 3192) on 08-25-2012, 12:52 PM:

Just as an update - a new CP750 is now on its way to us!

Posted by Carsten Kurz (Member # 5396) on 08-25-2012, 02:51 PM:

So it seems you now have moved from your original site to a new location, thus a new lens and new sound processor? What's different to the old location now? New amps/speakers as well? I remember in the previous location you had a stereo speaker setup?

- Carsten

Posted by William F Green (Member # 3192) on 08-25-2012, 05:33 PM:

Good memory Carsten! Yes, we had to leave the old location when our 10-year cinema business was hijacked by a local film club in collaboration with the town council, but that's another story...

The NEC NC800 and server package was originally bought with the first venue in-mind but due to the complications mentioned above was never installed (by the way I now have a spare very long-throw lens if somebody needs one!)

The new venue is a fairly comfortable 150 seat theatre in the same town. It has a balcony and absolutely nowhere to mount any 35mm equipment - hence the move to digital now (which would have happened anyway at some point soon).

The proj is to be mounted on the front of the balcony (which makes for a very short throw to the screen) and controlled/fed from a control room on the ground floor under the balcony. It's what you would call an 'intimate' venue in dimensions.

What else is new? We have a new 5m wide perf electric roll-down screen masked to 2.39.
We also have two additional amps on the way and some new but fairly modest stage speakers. The venue is pretty dead acoustically (the exact opposite of the last venue) and I don't anticipate any problems getting good sound in there. Sound will be 5.1 via the new CP750

This is all funded by me so finances are tight and much of the basic installation is being done by us and theatre staff. Once everything is lined-up and working we will have an engineer for a day (one of Pete Naples colleagues) to calibrate the sound and colour etc.

The screen is being fitted this week - wish me luck!

Posted by Pete Naples (Member # 761) on 08-26-2012, 04:38 AM:

I heard my name, don't wear it out!

I reckon the CP750 is the right choice for you, just to echo the sentiments above.

Good luck with it all William, I'm not sure who's coming to your gaff. I'd come myself but Brighton is a hell of a way. Although it's a place I've always fancied visiting. Maybe I'll do the London-Brighton run one of these days in whichever old car I've got on the road at the time.