New RME ADI-2 Pro EX DAC

[rcstevensonaz]

I got a mixer just to add mic preamps to an ADC converter (ADAT breakout) for measurement purposes, the primary interface handling clocking as Master.

Does that seem a logical approach?

You mean like an Ashly LX-308B that I am currently using for this?

 

[rcstevensonaz]

In the digital domain, there can only be one clock master in a system.

ASRC and re-clocking can allow input from external device to be matched to the internal clock of a host device. That is what ADI-2 pro already does with one digital input.

 

[KSTR]

I am only asking for ASRC on all digital inputs. Not that hard to do with modern compute power. They already do it on either one of the digital inputs; so just enable on both with the newer model.

It is done with a hardware chip in the ADI-2 Pro, not in DSP, so they would need two of these chips... not attractive, given the very rare use case.

 

[KSTR]

ASRC and re-clocking can allow input from external device to be matched to the internal clock of a host device. That is what ADI-2 pro already does with one digital input.

Per common developer lingo you have a clock domain boundary with ASRC, and potential issues as the resampling is not lossless and prone to intersample overs etc. Things are not as simple. Inside a DSP system as implemented in devices like the RMEs you always are in the same single clock domain.
EDIT: and the RMEs are already very flexible in that you can freely select the clock source for DSP/USB clock.

 

[KSTR]

And by the way, you can use the ADI-2 Pro like that, to run two digital audio input streams simultaneously:
- ASRC on SPDIF COAX/OPT
- Clock source on AES
- USB Multichannel mode (clock rate must match what is applied on AES)
- Mix in software/DAW, and return the signal to the DAC section

Quoting from the manual:
"For example having the ADI-2 Pro synchronized to an AES signal, a CD player connected to SPDIF input can only be used when the SRC is set to SPDIF. It then decouples the clock of the non-synchronizable CD player, preventing clock problems and drop outs."

 

[rcstevensonaz]

It is done with a hardware chip in the ADI-2 Pro, not in DSP, so they would need two of these chips... not attractive, given the very rare use case.

I don’t know their hardware chip. But an rPi seems to be able to handle quite a few channels at the same time. Reclocking / or even frequency sample rate change on a second stereo stream doesn’t seem to be a heavy lift.

And; this is an interface converter — that is its role. And this device is designed for multiple simultaneous input streams across 3 channels (of which 2 are digital) that are touted out for offboard mixing. So to me, this is not an esoteric request or a far stretch.

 

[KSTR]

I don’t know their hardware chip. But an rPi seems to be able to handle quite a few channels at the same time. Reclocking / or even frequency sample rate change on a second stereo stream doesn’t seem to be a heavy lift.

And; this is an interface converter — that is its role. And this device is designed for multiple simultaneous input streams across 3 channels (of which 2 are digital) that are touted out for offboard mixing. So to me, this is not an esoteric request or a far stretch.

See my post above. You can have your two async digital stream inputs running at the same time and mixed together, also adding in the ADC input.
The only thing you can't do is running both Coaxial and Optical SPDIF connectors as the are the same input.

 

[rcstevensonaz]

See my post above. You can have your two async digital stream inputs running at the same time and mixed together, also adding in the ADC input.
The only thing you can't do is running both Coaxial and Optical SPDIF connectors as the are the same input.

Just to clarify: can the AES input run in S/PDIF mode along with the other S/PDIF (optical, coax) input?

Also, with that configuration, I can no longer have option of sending out to the Digiface for mixing?

 

[KSTR]

But an rPi seems to be able to handle quite a few channels at the same time. Reclocking / or even frequency sample rate change on a second stereo stream doesn’t seem to be a heavy lift.

rpi4 has only stereo I2S audio interface, and rpi5 has I2S with four data lines, so four stereo channels. Only one I2S common clock for everything.

 

[rcstevensonaz]

a CD player connected to SPDIF input can only be used when the SRC is set to SPDIF. It then decouples the clock of the non-synchronizable CD player, preventing clock problems and drop outs

Yep. But allow that decouple on both digital inputs. At least, that is what I want.

 

[KSTR]

Just to clarify: can the AES input run in S/PDIF mode along with the other S/PDIF (optical, coax) input?

AES and SPDIF is the same thing, the same basic protocol, except for minor details the hardware electrical interface.
You can always attach an AES source to the SPDIF input and vice versa, as long as the hardware interface is working which is typically the case even without the officially required level shifting and impedance matching.

Also, with that configuration, I can no longer have option of sending out to the Digiface for mixing?

The only interface that allows multi-channel is USB, so no. Regardless of any configuration of the ADI-2 Pro.

 

[KSTR]

But allow that decouple on both digital inputs. At least, that is what I want.

Why?

 

[rcstevensonaz]

Why?

External AES would be master clock, and then ADI-2 would be slave clocked to that. When I then route digital out from the ADI2 to the Fireface USB, the Fireface would be slave to the slaved-ADI-2 pro… and that doesn’t work.

On other hand, I would be able to route via USB to a PC, and from there out to a the Fireface. Which works and is what I did for a while. But hoping to avoid the PC in the routing stream.

 

[KSTR]

External AES would be master clock, and then ADI-2 would be slave clocked to that. When I then route digital out from the ADI2 to the Fireface USB, the Fireface would be slave to the slaved-ADI-2 pro… and that doesn’t work.

I cannot follow, what is the transmission means you want to use to get your 4-channel data from the Pro to the Fireface? It can only be USB, obviously, and that requires a host that does the mixing and sends it to the Fireface via USB. And that still will not work, as one cannot run two USB devices that are not hardware-synced (external to the USB domain) so that they have the same clock, otherwise you'll get buffer over-/underruns after some time.

 

[john61ct]

You mean like an Ashly LX-308B that I am currently using for this?

I was talking to @KSTR

> so the solution is that one source remains the clock master and the other sources undergo a resampling to that master clock

asking a very specific question

I got a mixer just to add mic preamps to an ADC converter (ADAT breakout) for measurement purposes, the primary interface handling clocking as Master.

Does that seem a logical approach?

...

nothing to do with your use case, which I know near nothing about, nor mixers.

 

[ShiZo]

There are only two digital inputs, SPDIF and AES, is ASRC manual switching between the two (perhaps using presets for convenience) too complicated?

I always thought it would be a cool feature to automatically switch to native sample rate too. Hate to say it for such a menial task, such as day to day music (like youtube), movies, shows, podcasts etc

 

[KSTR]

I always thought it would be a cool feature to automatically switch to native sample rate too.

Well, for playback via USB this is already the case, the OS does that for your you (or not and chooses to resample the data).

If you meant that USB should adapt to what is present on an external SPDIF input for recording, this would require an extra mechanism to tell the host that the device wants to set a new sample rate, USB itself has no mechanism for this.
But it would not be RME if they didn't had a backdoor, the MIDI remote software protocol. You could read out the incoming SPDIF sample rate and tell the host software (if it has a software API, that is) to switch USB to that sample rate.

 

[BassTinker]

I found a belarusian DJ webshop in which the ADI-2 Pro EX and ADI-2/4 Pro EX are listed with a price difference of ~75€. Weirdly, the bigger version (2/4 Pro) is listed at 2.125€ while the smaller one (2 Pro) is roughly 2.220€. They are both ready to pre-order.

Even though the shop seems legit, they seem to have mixed up the models and I also cant really imagine such a small price difference.
I really don't want to get into politics here, but I am surprised to see Belarus sell new German products since the sanctions are in full operation. Of course, big amounts of sanctioned products still end up in Russia by ominous ways, in which the original manufacturer have no influence.

So....don't really know what to make out of that info

 

[rcstevensonaz]

> so the solution is that one source remains the clock master and the other sources undergo a resampling to that master clock

This seems to be the answer — a reclocker combined with sufficient buffer so that the output is sychronized to that master clock.

Obviously, that is not a useful solution if trying to capture simultaneously music sources from vocals and various instruments that are playing together and require precise clock aligment. But, a buffer-induced delay is no issue at all when playing back audio from various local and network sources when it does not matter if the audio starts a few milliseconds (or even seconds) late due to the buffering.

P.s., that is essentially what is already happening when I put a DAC in front of the analog stereo mixer for my audio sources anyway.

 

[BassTinker]

Two days ago (18th of June), RME released their first USB drivers that include not only the ADI-2 Pro EX, but also the ADI-2 DAC EX and the ADI-2/4 Pro EX.
To see it, go to https://rme-audio.de/adi-2-pro-fs.html --> DRIVERS --> USB --> Flash Update --> "Mac OS Flash Update Tool" and there you can find the following entries (amongst others):

ADI-2/4 Pro EX (Hw Rev 7): FPGA 314, DSP 100
ADI-2 Pro EX (Hw Rev 7): FPGA 418, DSP 128
ADI-2 DAC EX: FPGA 81, DSP 62

So the release announcement of the other devices shouldnt be too far away if they already released the first drivers for them