S/PDIF output

[dominicperry]

Thanks for the new S/PDIF out at the ADAT ports.

I'm trying to get this to work - I've set both ADAT 1 & 2 to S/PDIF in the hardware -> Optical i/o dialog box.

I'm outputting MON to A1-2 and have the Carbon connected to an RME ADI-2 Pro fs. This is connected to my speakers. I know the RME ADI-2 works like this because I normally have my RME Babyface connected to it, so I've just moved the cable across from the Babyface to the Carbon ADAT1 out.

PT plays back - I can see the meters working - but the RME displays "SPDIF NON-AUDIO" on the sync page.
The explanation in the RME manual is:
"But SPDIF and AES can also transport AC-3 and DTS encoded surround sound. This signal sounds like chopped noise at full volume. Therefore the ADI-2 Pro receiver circuit checks the Non-Audio flag within the Channel Status. If found the signal is already muted directly in the receiver. An error message is shown in red colour in the lowest line, saying SPDIF NON- AUDIO, explaining why there is no sound at the analog outputs despite a valid input signal."

So, am I configuring something wrong with the output of the Carbon, or is it just not compatible with the RME ADI-2?

Thanks

Dominic

[Kyle Splittgerber]

Originally Posted by dominicperry

Thanks for the new S/PDIF out at the ADAT ports.

I'm trying to get this to work - I've set both ADAT 1 & 2 to S/PDIF in the hardware -> Optical i/o dialog box.

I'm outputting MON to A1-2 and have the Carbon connected to an RME ADI-2 Pro fs. This is connected to my speakers. I know the RME ADI-2 works like this because I normally have my RME Babyface connected to it, so I've just moved the cable across from the Babyface to the Carbon ADAT1 out.

PT plays back - I can see the meters working - but the RME displays "SPDIF NON-AUDIO" on the sync page.
The explanation in the RME manual is:
"But SPDIF and AES can also transport AC-3 and DTS encoded surround sound. This signal sounds like chopped noise at full volume. Therefore the ADI-2 Pro receiver circuit checks the Non-Audio flag within the Channel Status. If found the signal is already muted directly in the receiver. An error message is shown in red colour in the lowest line, saying SPDIF NON- AUDIO, explaining why there is no sound at the analog outputs despite a valid input signal."

So, am I configuring something wrong with the output of the Carbon, or is it just not compatible with the RME ADI-2?

Thanks

Dominic

Hi Dominic,

Looks like you just need to mult the MON L-R output mapping to ADAT 1-2 in I/O setup. See the steps starting on page 20 here, for info on how to do that.

[dominicperry]

Hi Kyle,

I've done that (mirror the output) and the error is the same - no output as the RME ADI2 is muting the signal because it sees the S/PDIF input as a non-audio source.

Any ideas?

Dominic

[Kyle Splittgerber]

Originally Posted by dominicperry

Hi Kyle,

I've done that (mirror the output) and the error is the same - no output as the RME ADI2 is muting the signal because it sees the S/PDIF input as a non-audio source.

Any ideas?

Dominic

Ahh, ok. How are the RME ADI2 and Carbon clocked to each other? And, are both devices at the same sample rate?

[dominicperry]

Originally Posted by Kyle Splittgerber

Ahh, ok. How are the RME and Carbon clocked to each other? And, are both devices at the same sample rate?

They're clocked over S/PDIF - there's a lock, I can see from the display of the RME that the Carbon is outputting 44.1 SPDIF over optical and it's pro level 16 bit. But it's also "non-audio" according to the RME-ADI2, implying a DTS or AC-3 stream.
The ADI-2 will chase the sample rate of the incoming signal from 44.1 to 768 and can cope with 16 and 24 bit, consumer and pro encoding.

[Kyle Splittgerber]

Originally Posted by dominicperry

They're clocked over S/PDIF - there's a lock, I can see from the display of the RME that the Carbon is outputting 44.1 SPDIF over optical and it's pro level 16 bit. But it's also "non-audio" according to the RME-ADI2, implying a DTS or AC-3 stream.
The ADI-2 will chase the sample rate of the incoming signal from 44.1 to 768 and can cope with 16 and 24 bit, consumer and pro encoding.

I see. Let me check in with the team on this. Thanks.

[Kyle Splittgerber]

Hi Dominic,

We're still looking into what the root cause could be for this issue. We tested a number of different audio devices before releasing the feature, but didn't see this problem. In the meantime, can you use ADAT format instead of S/PDIF? I see the ADI-2 Pro supports it:

"The optical SPDIF input is fully compatible with all ADAT optical outputs. The internal receiver detects the format and automatically switches between SPDIF and ADAT mode. RME's unsur- passed Bitclock PLL prevents clicks and drop outs even in extreme varipitch operation, and guarantees a fast and low jitter lock to the digital input signal. A usual TOSLINK cable is suffi- cient for connection.

To not break the concept and to simplify operation, only channels 1/2 of the ADAT input signal are taken. Even in multi-channel USB mode ADAT uses only the SPDIF input channels 5/6 – not more. Still the information of all 8 ADAT channels is used in two cases: in SMUX (96 kHz) and SMUX4 (192 kHz) operation, where channels 1/2 are built up from the information spread about 4 and 8 channels. And in Digital Through mode, where only channels 1/2 can be moni- tored, but all 8 channels are passed through to the output if set to ADAT."

[dominicperry]

Originally Posted by Kyle Splittgerber

Hi Dominic,

We're still looking into what the root cause could be for this issue. We tested a number of different audio devices before releasing the feature, but didn't see this problem. In the meantime, can you use ADAT format instead of S/PDIF? I see the ADI-2 Pro supports it:

"The optical SPDIF input is fully compatible with all ADAT optical outputs. The internal receiver detects the format and automatically switches between SPDIF and ADAT mode. RME's unsur- passed Bitclock PLL prevents clicks and drop outs even in extreme varipitch operation, and guarantees a fast and low jitter lock to the digital input signal. A usual TOSLINK cable is suffi- cient for connection.

To not break the concept and to simplify operation, only channels 1/2 of the ADAT input signal are taken. Even in multi-channel USB mode ADAT uses only the SPDIF input channels 5/6 – not more. Still the information of all 8 ADAT channels is used in two cases: in SMUX (96 kHz) and SMUX4 (192 kHz) operation, where channels 1/2 are built up from the information spread about 4 and 8 channels. And in Digital Through mode, where only channels 1/2 can be moni- tored, but all 8 channels are passed through to the output if set to ADAT."

Thanks Kyle.
I'll try using ADAT instead, although it didn't work before this firmware version, I didn't get a lock at all. I'll report back.

Dominic

[dominicperry]

Kyle, yes, that works as ADAT now, thanks.

It only works inside Pro Tools, which is a pity but I can work round that. Using channels 11+12 in "Configure Speakers" doesn't send normal output to those channels, so outside of PT I need to use the analog main outputs, but inside PT that works with the ADI-2 now, thanks.

Dominic

[Kyle Splittgerber]

Originally Posted by dominicperry

Kyle, yes, that works as ADAT now, thanks.

It only works inside Pro Tools, which is a pity but I can work round that. Using channels 11+12 in "Configure Speakers" doesn't send normal output to those channels, so outside of PT I need to use the analog main outputs, but inside PT that works with the ADI-2 now, thanks.

Dominic

Ok, glad that's a workaround for you.

And, yes AMS doesn't allow the Speaker assignment to be routed to multiple outputs like Pro Tools does. So, we'd need to add a true digital mirroring feature to get around this.