Cp950

[Carsten Kurz]

If I remember right, Dolby even called the CP950 a 'drop-in replacement' for the CP750. Well...

I figured out it wouldn't even be so complicated to make a 6ch analog input card using the AES inputs. A/Ds are cheap nowadays, but they would need to be synchronized, and these are a lot more expensive than a couple ordinary stereo converters.

- Carsten

[Steve Guttag]

The thing is...there is pretty much NOTHING drop-in about it for replacing a CP750. None of the cables (save the 1x AES) are the same and as an added insult to injury, they transpose the connectors, down to the power cord so any wire-dress you may have done, has to be redone too! If you used Toslink (as some satellite and cable boxes use), that is gone and the obvious 8-channel analog input. You do get an HDMI in/out though, which is nice, though it is allergic to DTS for obvious reasons.

[Marcel Birgelen]

I think that Dolby not shelling out a few bucks for at least a basic set of DTS licenses for the discrete channel formats offered by DTS is kind of stupid though, especially due to the lack of a 6ch analog-in option. Besides someones notebook, BluRay is most likely one of the most common alternative content sources and some only come with an AC3 mix and only with lossless version of the soundtrack in DTS-HD. Yes, it is the competition, but how can you beat the competition? By offering either a cheaper or a better product than they offer, this often includes embracing standards by the competition, so you can actually compete...

I figured out it wouldn't even be so complicated to make a 6ch analog input card using the AES inputs. A/Ds are cheap nowadays, but they would need to be synchronized, and these are a lot more expensive than a couple ordinary stereo converters.

There are very low-latency stereo analog to AES DACs, I guess a bunch of them, even unsynchronized, would work pretty well. Actually, as long as the jitter in latency between the channels is in the miliseconds, it should be "good enough".

[Ioannis Syrogiannis]

... On female connectors, the standard says "Connectors mounted on equipment shall be female (socket) type. Connectors on free cables shall be male (pin) type." "NOTE equipment-mounted connectors may be difficult to replace in case of damage, and female connectors are substantially less likely to suffer mechanical damage. The risk of deformed pins in a cable-mounted male connector is offset by the ability to repair or replace a cable at lower cost."

I don't know which standard that is, but I am happy that it's finally there.
I haven't got to bend a pin on an audio processor (yet), but I have found one or two that needed to be fixed or were bended and I was trying to straighten, praying not to be the lucky guy with the bomb blowing in my hands. One CP750 had a problem with two channels and a fast inspection showed that a pin was pushed half way back (and others less than that, for the sake of data transfer, I won't upload photos). Makes you wonder for how long that was in that state and how hard the guy that was trying to connect the audio output was pushing, instead of pausing and having a better look.
Using a male connector is an intuitive way to define an output, but I very much welcome such standards.

... None of the cables (save the 1x AES) are the same...

Yes, you can hardly add the non-synced sources in the list. I guess that if the P/A microphone wasn't mandatory on (some?/all?) cinemas, all analog inputs would have been long gone by now.

[Steve Guttag]

I'll tell ya Harold, I can't remember the last time I had a chassis mounted Dsub with a crushed/bent pin. Chassis mounted Dsubs tend to also use machined pins, making them tend to be straighter and less likely to be in a bending situation. So are you going to get all microphones to use female connectors for their or is this just a Dsub thing? Is it better to be in a world where we have uniformity due to established methodology or is it better to have complete inconsistency due to a perceived benefit decades after the established? We are not talking about any performance benefit to the new method but we are introducing inconsistency.

Yes, Ioannis, I did, accidentally, omit the Non-Sync and Mic inputs, thanks for the catch!

[Marcel Birgelen]

Dolby needs to realize that professional audio, up until this very day, largely remains an analog affair. Or, at least, the analog part of it will remain an important part for the foreseeable future.

For professional video, you have SDI in its various bandwidths as the de-facto standard for interconnects (yes, I'm oversimplifying a bit), but for audio, there is not really such a thing. We've had AES/EBU for years, but balanced analog over XLR remains the de-facto standard up to this very day. And even in professional audio, you can't always avoid the occasional unbalanced analog interconnect...

The difference already starts in how we nowadays capture video versus audio and subsequently play it back. For video, an all-digital pipeline certainly makes sense. In modern video-cameras, everything that comes after the sensor is essentially purely digital. The same is for "presentation", whether it's an LCD/OLED screen, a video-wall or a projector, the signal remains digital up until it hits the very sub-pixel. Yes, "the signal" certainly gets transformed many times, but all those transformations, whether it's compression, decompression, encryption, decryption, scaling, color correction, etc. etc., they're all digital algorithms.

This is different to how we capture audio, whether it's via microphone or on a transducer in e.g. a musical instrument like the pickup in an electric guitar. And it's also different to how we produce audio, by converting an analog electric signal into moving air.

While mixing and editing audio is nowadays almost always a digital affair, the analog chain in audio remains longer. While stuff like Q-Sys renders most analog interconnects superfluous, it's still not the norm and certainly not for small scale cinema deployments. And up until this very day, you can't simply buy a microphone that plugs directly into your HDMI port...

[Ioannis Syrogiannis]

Yes, you can hardly add the non-synced sources in the list.

Now that I think about it, I should have used "one" instead of "you", Steve.
I would have avoided misunderstandings and unnecessary tentions.
(Where is the "V sign" smiley in this forum?)

[Mark Gulbrandsen]

The short answer on the CP950 is NOTHING is the same as the CP750...not even the power cord is on the same side!

Because the CP-750 is such a dinosaur the engineering team retired long ago!

Mark

[Stefan Scholz]

AES67/ blue link output. Great. Finally networked audio, that is standard for years. There's compatibility for legacy power amps with balanced in, and you can even do a active xovers.
Analog multichannel in, ok, but this box is basicly a video switch box, and not a main gear. For more than 3 auditoriums QSYS is the better alternative. How many of the older theatres with a few screens actually do film ? The last we did, I kept the CP 650 in place, and used a relay switchbox in front of the power amps. But how many movies are these non profit people really goin to screen. Film rapidly became an archival artefact, the borders for screening actual film prints are extremely. And one of my friends in a museum institution is so pissed about the archival habitat, the wants to quit, stating, those are copies, not originals.
So the demand is very limited for analog sources.
In the theatres it is targeted for, it does a good job.
The cons are in setup, you need the DAD program and the web browser based setup screen. The DAD requires a complete definition of the auditorium, so it is not that easy to "just rush in and do a quick, dirty job".
The auto EQ with the plexer does an oK job, when in a hurry, and that compensated for some time I would have spent otherwise. Even though it does not fully replace a manual tuning day with R2/ D2.
But for those with outdated 2 way speakers and small surrounds…
The bass management can do good, but adjustment of the LFE is tricky, it's lacking a steep LPF, which I need in my theory. I do not trust sound designers. It takes time, but possible.
And the thing with the Tascam out, finally, the THX standard that was based on the CP200 ribbon cable to DB 25 is history. All other gear has always relied on the Tascam/ Yamaha, … pinout. So finally I was able to use off the shelf connection cables, and not sit there soldering DB 25 THX to Yamaha cables. But that depends on individual system setups and other gear. Mainly my sound systems are based on Yamaha DME as main gear, and then, you get a different image.
For some 10+ years now, you weren't really interested in analog feeds betwen equipment, A/D, D/A, A/D, D/A is not the goal. So EBU 3 was a viable option. Today AES 67 is simplier and these or BluLink inputs can be found on many professional audio gear.
The CP950 is a design from around 2020, and not 2000. 20 years have lead to new standards. Accepting that, it is ok.

[Steve Guttag]

THX standard that was based on the CP200 ribbon cable to DB 25 is history.

The THX standard was NOT based on the CP200 ribbon cable. The unbalanced pinout was based on the CP200 ribbon. The THX pinout was always balanced.

For your reading pleasure, Odyssey has a sheet of the various analog pinouts used: https://c3f18fc2-65b9-4e62-8935-5869...f7c52039c6.pdf

The Tascam "standard" is nothing new...just wasn't used in cinema until recently. There just wasn't a need to add another pinout to the mix of things and using the same gender for inputs and outputs is just plain bad engineering. Ever seen an analog system feedback on itself...it is harder when one has M/F cables than M/M and all of the chassis connectors are Female.

As to analog inputs (multi-channel), They do tend to get used by us on the overwhelming majority of our systems...be it because of a film processor upstream or a Blu-ray player to something else. I do consider it a mistake to not include it on the CP950 and it will/has limited it usability for us. We have put the CP950 in and it has done what we have expected of it. An oddity though is the lip-sync delay for non-DCP sources...it starts at 80msec or so and we ran into a case with a dish system that it wouldn't lock onto the S/PDIF signal until the lip sync was raised to 100 (it is a know bug that I suspect will be fixed on the next release, but still, 80msec is long).

[Leo Enticknap]

Because the CP-750 is such a dinosaur the engineering team retired long ago!

It might be a dinosaur as far as Dolby's development and support teams are concerned, but it is still very current for, likely, tens of thousands of movie theater auditoria. I was also given the "drop in replacement" line during the CP950 seminar, only to discover that it actually isn't, in many ways. Power cord on the wrong side (admittedly a minor issue, but having to snip zip ties, re-run the cable, maybe even replace it if it was cut to a certain length and there is no slack, and then put new zip ties in, is a few minutes that you wouldn't have to spend if the C14 jack were on the same side), no multi-channel analog input, you can't take a tuning settings backup out of a CP750 and upload it into a 950, you've got to work up a DAD design, even for a regular 5.1 or 7.1 house ... as of now, the only truly drop-in replacement for a 750 is another 750.

[Steve Guttag]

...you've got to work up a DAD design, even for a regular 5.1 or 7.1 house

I've yet to do a DAD program for a 5.1 or 7.1 house (done both). You only need to use the DAD if you are using internal crossovers (if you are going to use the second analog output).

[Scott Norwood]

Out of curiousity, do these things work for analog audio?

http://www.cablesonline.com/rsdbmajubox.html

This is an "RS232 jumper box" and is used for connecting cables to things with different pinouts. It has two DB25s and a number of jumpers that can be soldered between them. This sort of thing seems like an easier option for converting from, say, the THX to Tascam pinout than re-making a cable. I have used them before for serial lines, but can see them being useful for audio, too, unless there is a reason not to do this (hum, interference, noise, etc.). Is there?

Also, I kind of agree with the standard that chassis-mount connectors should always be female (which is why the male DB9 serial port on PC hardware has always annoyed me), but Steve makes a good point that this doesn't really make sense for audio signals. Hmm....

[Bruce Cloutier]

Just remember that the really good thing about standards is that there are so many to choose from.

[Steve Guttag]

Scott, have you ever had the serial port on a computer fail because the pins got bent? I've never had one fail...ever and that is with 1000s of cycles. The arguments for all female chassis DSubs is a fix for a non-existent problem. Sure there are going to be cases in point but their are not going to be significant numbers.

Odyssey Products already has the Tascam to THX adapter board done


I swear it is a conspiracy to keep Odyssey Products in business. Their slogan could be: "If manufacturers knew how to make their products interface well, they wouldn't need us." My hat is off to Odyssey Products, about as fast as new products hit the streets, they are churning out boards/cables to make them easier/better to install.