DOLBY CP750

[Alleorla11]

Hi everyone, I found a Dolby processor without a power supply for 80 euros and I bought it immediately. I already know that the power supply will cost me above 100 euros, hoping that the card won't have any problems either, but I wanted to take a risk. Unfortunately I'm not a cinema person and I'm passionate about audio and I'm learning as I go. I made this post because I would like to use it in my room, for the moment I have a 5.1.2 home system using an onkyo nr-tx545 and even if I lose the atmos channels since there are no great films anyway I would like to use the dolby processor with 8 amplifiers that I have, I would need the audio cable that goes from dolby to the amplifiers, I know that the cable is already ready but I'm not sure which one would be suitable. Furthermore, I would like to understand how I can use it while also watching the film on TV. I have a truenas server available (maybe there is a way to switch only the audio to dolby), plus I can understand how to watch the video part too. Then I have nvidia shield pro available. Or is the only solution to send the audio via optical cable from the TV to Dolby? Although I don't know if good audio comes through. Tell me what is best to do to be able to use it in the room, thanks

 

[mdsimon2]

If you want to get 8 channels into the CP750 the only way is 4x AES in PCM format. BNC and optical inputs can do Dolby AC-3 (5.1), but no more and it will be compressed.

Some retail options for 4x AES.

VanityPro (HDMI to AES): https://audiopraise.com/projects/internal/vanitypro/
MiniDSP U-DIO8 (USB to AES, discontinued): https://www.audiosciencereview.com/...dsp-u-dio8-usb-to-aes-converter-review.10919/

There are a lot of DIY options that can do USB to 8 channel I2S (miniDSP USBstreamer, miniDSP MCHStreamer, Raspberry Pi 5) but you will need I2S to AES boards and probably a clock buffer (https://kaamostech.com/product/clock-buffer-1-4/).

Michael

 

[Alleorla11]

If you want to get 8 channels into the CP750 the only way is 4x AES in PCM format. BNC and optical inputs can do Dolby AC-3 (5.1), but no more and it will be compressed.

Some retail options for 4x AES.

VanityPro (HDMI to AES): https://audiopraise.com/projects/internal/vanitypro/
MiniDSP U-DIO8 (USB to AES, discontinued): https://www.audiosciencereview.com/...dsp-u-dio8-usb-to-aes-converter-review.10919/

There are a lot of DIY options that can do USB to 8 channel I2S (miniDSP USBstreamer, miniDSP MCHStreamer, Raspberry Pi 5) but you will need I2S to AES boards and probably a clock buffer (https://kaamostech.com/product/clock-buffer-1-4/).

Michael

I don't want to use an external DSP, I would like to use the Dolby connected to 8 outputs, the best thing is to have the signal from the TV enter the Dolby, I was thinking about the optical but as you said it is compressed, I don't have any other ways from HDMI and go to Dolby?

 

[staticV3]

I don't want to use an external DSP, I would like to use the Dolby connected to 8 outputs, the best thing is to have the signal from the TV enter the Dolby, I was thinking about the optical but as you said it is compressed, I don't have any other ways from HDMI and go to Dolby?

If you want to use all eight of the CP750's output channels for surround sound, then you need to decode the surround sound format externally and feed it into the CP750 as LPCM via AES3, or as Analog Line signal.

The only way to get 8ch surround sound with internal decoding is via Dolby Surround EX, which AFAIK is not available to consumers.

Edit:
It's possible that the CP750's Surround EX decoder also supports the consumer version of that format labeled Digital EX, but this is not stated explicitly.
Even then, Digital EX is hardly a common surround format.

 

[mdsimon2]

I don't want to use an external DSP, I would like to use the Dolby connected to 8 outputs, the best thing is to have the signal from the TV enter the Dolby, I was thinking about the optical but as you said it is compressed, I don't have any other ways from HDMI and go to Dolby?

None of the devices I mentioned are DSPs, they are ways to get 8 channels of digital output in AES format from USB or HDMI from your Shield Pro.

Michael

 

[Alleorla11]

If you want to use all eight of the CP750's output channels for surround sound, then you need to decode the surround sound format externally and feed it into the CP750 as LPCM via AES3, or as Analog Line signal.

The only way to get 8ch surround sound with internal decoding is via Dolby Surround EX, which AFAIK is not available to consumers.

Edit:
It's possible that the CP750's Surround EX decoder also supports the consumer version of that format labeled Digital EX, but this is not stated explicitly.
Even then, Digital EX is hardly a common surround format.

And if I wanted to get 5.1, therefore 6 channels, would it be the same thing? At this point, would it be better for me to connect all the devices with HDMI to the TV and then exit the TV with an optical cable and connect it to the Dolby? Even though it will unfortunately be compressed, right now I'm using an Onkyo TX-NR545 5.1.2, which I would like to replace with the Dolby processor.

 

[Alleorla11]

None of the devices I mentioned are DSPs, they are ways to get 8 channels of digital output in AES format from USB or HDMI from your Shield Pro.

Michael

Is there anything cheaper that converts HDMI to 6-channel AES?

 

[staticV3]

And if I wanted to get 5.1, therefore 6 channels, would it be the same thing?

5.1 is super easy via Dolby Digital from any TV, BD Player, game console, Apple TV, Roku etc using Toslink.

At this point, would it be better for me to connect all the devices with HDMI to the TV and then exit the TV with an optical cable and connect it to the Dolby?

As long as the TV supports Dolby Digital pass-through, yes.

 

[Alleorla11]

5.1 is super easy via Dolby Digital from any TV, BD Player, game console, Apple TV, Roku etc using Toslink.


As long as the TV supports Dolby Digital pass-through, yes.

Yes, it supports it, so is it better to use an optical cable? I was looking for a converter where I connect the HDMI and then it converts to AES.

 

[staticV3]

Yes, it supports it, so is it better to use an optical cable? I was looking for a converter where I connect the HDMI and then it converts to AES.

AES offers no advantage over Toslink for sending Dolby Digital 5.1, so you can save the money and connect straight to your TV.

 

[Alleorla11]

AES offers no advantage over Toslink for sending Dolby Digital 5.1, so you can save the money and connect straight to your TV.

I understood that the audio is compressed using the optical cable. Regarding a power amplifier, what do you recommend that has 6 XLR inputs?

 

[staticV3]

Regarding a power amplifier, what do you recommend that has 6 XLR inputs?

Alsozone PAM156/PAM256 would work.

Otherwise you can buy MCH Amps from VTV Amplifier, Nord Acoustics, Buckeye Amps, Monoprice, Apollon Audio, Audiophonics etc.

Just see what fits your budget, power needs, and location/service/warranty expectations.

They all are audibly transparent.

 

[Alleorla11]

Alsozone PAM156/PAM256 would work.

Otherwise you can buy MCH Amps from VTV Amplifier, Nord Acoustics, Buckeye Amps, Monoprice, Apollon Audio, Audiophonics etc.

Just see what fits your budget, power needs, and location/service/warranty expectations.

They all are audibly transparent.

OK, do you think it makes sense to lose some of the audio formats I have with my Onkyo to install Dolby CP750? Let's say that with Dolby I would have more audio settings, hoping that the Dolby software will let me access them. I also wanted to ask you, to send the audio I use the optical cable but to send the audio to the speakers I would need the DB25 to XRL cable I imagine, can you link it to me?

 

[staticV3]

OK, do you think it makes sense to lose some of the audio formats I have with my Onkyo to install Dolby CP750? Let's say that with Dolby I would have more audio settings, hoping that the Dolby software will let me access them.

I have no experience with Dolby hardware, so cannot answer that unfortunately.

I also wanted to ask you, to send the audio I use the optical cable but to send the audio to the speakers I would need the DB25 to XRL cable I imagine, can you link it to me?

Sure, here's the cable: https://www.google.com/search?q=db25+to+xlr

 

[Alleorla11]

I have no experience with Dolby hardware, so cannot answer that unfortunately.


Sure, here's the cable: https://www.google.com/search?q=db25+to+xlr

So are they already ready or do I have to modify some cables? What else can you tell me? Do you have that Dolby and do you recommend using it in my room at home with normal front speakers and JBL 8330 surround speakers, i.e. there is no problem with 8 ohm speakers.

 

[staticV3]

So are they already ready or do I have to modify some cables?

The are ready. No need to modify.

What else can you tell me?

What else do you want to know?

Do you have that Dolby

See my previous message.

do you recommend using it in my room at home with normal front speakers and JBL 8330 surround speakers, i.e. there is no problem with 8 ohm speakers.

It's a surround processor with Line out. Why would the type of speakers matter? The CP750 does not interact with any speakers. That's the job of your Amplifier.

 

[Alleorla11]

The are ready. No need to modify.


What else do you want to know?


See my previous message.


It's a surround processor with Line out. Why would the type of speakers matter? The CP750 does not interact with any speakers. That's the job of your Amplifier.

Oh, okay, I'm a little new. Is it worth switching from modern lossless audio formats to Dolby Digital/Dolby Surround?

 

[staticV3]

Oh, okay, I'm a little new. Is it worth switching from modern lossless audio formats to Dolby Digital/Dolby Surround?

You'll just have to give it a try and decide for yourself.

Your priorities and preference play a major role here, so this is not something that others can answer for you.

 

[Alleorla11]

You're right, I'll have to test and figure it out. Do you have a theater? Do you have or had that processor? What would you install or use at home?

 

[staticV3]

Do you have a theater?

I do not.

Do you have or had that processor?

This is the second time now that you've asked me if I own the CP750, after I've already told you twice that I have no experience with Dolby hardware:

I have no experience with Dolby hardware

See my previous message.

I don't understand. Is this a language barrier issue? Or reading comprehension?

What would you install or use at home?

That depends entirely on the listening environment (room size, neighbors, etc) and the budget.