CP950 Bass Management Caballing

[Rob Jeromson]

Evening, our new build is using Dolby CP950's in a 7.1 set-up and were intending to use the 1-8 & 9-16 analog outputs for connection to the amplifiers. My question is related to caballing and routing to use bass management on the surrounds. Is there specific pins to connect on the DB25 connector, and how is this routed in the processor? Many thanks.

[Marcel Birgelen]

If you use bass management on the processor itself, there should be no extra cabling involved, as the processor routes the selected frequencies below cutover to the selected bass management speaker internally.

If you use other bass management solutions independent from the processor, the situation may be different and dependent on that particular solution.

[Rob Jeromson]

Thanks for your reply, how do you cable the crossover frequencies to a dedicated subwoofer?

[Marcel Birgelen]

The routing is done internally and digitally inside the processor. There is no extra cabling involved. The idea of bass management is that the processor summons all the frequencies of all the selected sources (to be "bass managed") below the selected crossover frequency to one or more speakers that can handle the frequency range at the required power level. In a 7.1 setup, this is usually your already existing "LFE speaker" or subwoofer.

[Rob Jeromson]

Thanks again, we have two subwoofers, a dual and a single, does that change anything?

[Marcel Birgelen]

Thanks again, we have two subwoofers, a dual and a single, does that change anything?

I'm not sure if the 950 supports it without the Atmos upgrade (need to check on that one), but you could designate one of the subwoofers to be the subwoofer that receives the bass management from the surrounds. This could improve the clarity of the lower end of the frequency band. But if that's desirable and possible also depends a bit on how those subwoofers are located in the room and on your amplifier configuration, although I suspect you have independent amplifiers for both subs.

[Rob Jeromson]

Yes, independent amps.

[Elia Orselli]

If you use DAD for CP950 configuration and tuning, in a 5.1/7.1 setup you can add more than 1 LFE channel (populate section > screen wall tab > LFE channels). After that, in the define section you'll set speaker type, output routing and you'll enable bass management for that LFE

[Steve Guttag]

Note, you do not have to have a dedicated bass management channel. You have have the subwoofer function as both the LFE and the bass management speaker. Leave the number of LFE channels at 1 and when you get to the bass management tab, you then assign the speakers you want bass managed to that subwoofer and define the crossover point on a speaker-by-speaker basis. You could have a different center speaker than left and right, for instance, and pick different crossover points for the different types of speakers.

Screen Shot 2023-06-13 at 8.08.58 AM.png

In the example above, I left it at the default frequency of 80Hz for all three screen channels.

For sure, "DAD" is an awkward program and, in my opinion, should not be necessary for a typical 5.1 or 7.1 installation. Dolby should have such a mode already in the CP950, including allowing for setting up crossovers and bass management. Alas, this is not the case. About all one can do, out of the box, with the CP950 is hook up a straight up 7.1 system without crossovers. The moment you want to do anything special (e.g. crossovers), you are stuck with configuring in DAD first. Again, they could have sped the process up by having a 5.1 and 7.1 mode that just wipes out half the questions. It is clear that DAD (Dolby Atmos Designer) was thinking "Atmos" and has all of the steps and configuration to deal with a 64 (individually assigned) speaker system. And even that, after one spends a fair amount of time on the design in DARDT (the spreadsheet for Atmos), DAD can't directly import the result (current DARDT does give the x,y coordinates on one of the tabs). Again, DAD is clunky/awkward and this extra program one has to deal with on the CP950 and is the "Auto-Tune" program too.

I should point out, Dolby does have a "preconfigured" file for DAD for a 7.1 system. From that you can delete off the rear wall speakers for a 5.1 and still define bass management. You can also modify it for screen channel crossovers in a multi-way system. The idea is, they are starting you off with much of it configured as you would want and you just have to massage it to what you need. I, still, would prefer just defined 5.1 and 7.1 modes but this is easier for them as it remains just the one program and it is up to the user to define the room correctly.

[Stefan Scholz]

It works quite nice, it is configured using the Dolby Atmos Designer to configure it. And that's some task, for somebody not familiar with the software. It will be frustrating. AS you have to enter a project first, than make your settings and adjust.
Combining it with their auto tune algorithm, 8 mic solution, it was the first time, I actually liked auto calibration.

[Jim Cassedy]

Make Sure You Use The Right Adapter Plug!
AtmosAdapter.jpg
JimC

[Marcel Birgelen]

Now, that's what I call a... plug.

Want to see the XLR version of it?

[Jim Cassedy]

Now, that's what I call a... plug

In technical nomenclature it's a T-R-R-R-R-R-R-R-R-R-R-R-R-R-R-R-S !