Topic: SRC Questions

When integrating the ADI-2 Pro FS BE (which I'm about to purchase) into a multitrack studio I have a workflow question as to how best to set up the converter for multitrack mixdown.

The stereo mix audio will be coming to the ADI as analog stereo audio and sent back to computer via UFX AES. The audio is a combination of in the box processing @ 44.1khz but soon to be 96 Khz (using Raydat card ) and then sent out to 16 channel analog summing where about 10 of those 16 channels have analog  transformers, eq, compressors and other "colour' type processing. It all gets summed together and sent to ADI-2 Pro FS BE analog input.

Since even at 44.1khz there's a fair bit of analog colour going on I'm thinking the mixdown audio would benefit from being sampled at higher than 44.1Khz. According to the ADI manual, optimal setting for ADI input record is 192 Khz.

So I can either achieve 192Khz for the ADI-2 FS BE recording while not sync'd to the rest of my audio system (UFX & 2 x Cranborne Audio Adat500 converters) or I can connect the ADI-2 to a second computer via USB and run internal clock on ADI and just record mixdown at 192Khz that way.

Will I hear a difference? I know I can test this when I get the box but would be good to get some other views on this.

Additionally if Idid try to use ADI SRC and mixdown using just one computer how is it even possible to send back 192Khz audio to a UFX AES input for recording when the UFX MUST be sync'd to 44.1Khz with the rest of the system?

Kind regards

__________________________
Paul Najar
Jaminajar Music Production
www.jaminajar.com

Re: SRC Questions

connect the ADI-2 to a second computer via USB and run internal clock on ADI and just record mixdown at 192Khz that way.
I would do it this way. And I have that feeling it is not possible other way.
is it even possible to send back 192Khz audio to a UFX AES input for recording when the UFX MUST be sync'd to 44.1Khz with the rest of the system?
From my poor knowlege, no, not possible, but I don't have those devices and can't say 100%.
in general every digital audio unit must be synced to the masters samplerate.

M1-Monterey, Madiface Pro, Digiface USB, Babyface silver

3

Re: SRC Questions

paulnajar wrote:

Since even at 44.1khz there's a fair bit of analog colour going on I'm thinking the mixdown audio would benefit from being sampled at higher than 44.1Khz. According to the ADI manual, optimal setting for ADI input record is 192 Khz.

The manual mentions this for Preamp mode, means AD and DA serially. The AD side is more open (to say it in an easy way) and will not limit or colour the recording even at 44.1 kHz. For peace of mind save some resources and use 88.2 or 96 kHz instead of 192 kHz.

paulnajar wrote:

Additionally if I did try to use ADI SRC and mixdown using just one computer how is it even possible to send back 192Khz audio to a UFX AES input for recording when the UFX MUST be sync'd to 44.1Khz with the rest of the system?

Correct, that won't work. And the SRC only works as clock decoupler for the digital input. I don't see the use case in your setup.

Regards
Matthias Carstens
RME

Re: SRC Questions

Thanks for the replies wadi and Matthias.

One other use example i would appreciate advice on please. I also plan to use ADI-2 FS BE as control room monitor feed for speakers. During tracking and editing input is fed via UFX AES running at 44.1 or 48Khz. Is it worth using SRC here so I can set ADI to 96 or 192 Khz and would this improve reproduction in this example by moving anti aliasing filters further away from audible spectrum?

__________________________
Paul Najar
Jaminajar Music Production
www.jaminajar.com

5 (edited by KaiS 2021-03-06 12:02:35)

Re: SRC Questions

paulnajar wrote:

I also plan to use ADI-2 FS BE as control room monitor feed for speakers. During tracking and editing input is fed via UFX AES running at 44.1 or 48Khz. Is it worth using SRC here so I can set ADI to 96 or 192 Khz and would this improve reproduction in this example by moving anti aliasing filters further away from audible spectrum?

In my experience, yes, there is a tiny advantage if you start with 44.1 kHz.
It‘s by no means night and day!

And no, I don’t hear any difference with different cables of any type smile - just to show where I’m coming from.

6

Re: SRC Questions

paulnajar wrote:

One other use example i would appreciate advice on please. I also plan to use ADI-2 FS BE as control room monitor feed for speakers. During tracking and editing input is fed via UFX AES running at 44.1 or 48Khz. Is it worth using SRC here so I can set ADI to 96 or 192 Khz and would this improve reproduction in this example by moving anti aliasing filters further away from audible spectrum?

Not at all. The SRC itself has to use a very similar filter, based on the basic sample rate. Technically it is not possible otherwise, without getting aliasing style distortion effects.

To illustrate that I measured the filter of the ADI-2 Pro DAC side set to Sharp at 44.1 kHz. Then I activated the SRC and set the sample rate to 88.2 kHz Int.. Yes, the filters of the DAC chip are now completely out of the way as they try to act at 44 kHz - where nothing is happening (no content). But the filter that one might hope to get rid of is still there - this time within the SRC. Not 100% identical (it has its own filter that does not duplicate one of those available in the DAC), but the difference is irrelevant. Point is there will always be such a low filter and there is no reason to believe anything gets better when upsampling.

https://archiv.rme-audio.de/images/adi2pro_da_filter_comparison_dac_src.png

Note this a zoomed view 10 kHz to 30 kHz, and the grey line is at 22.05 kHz.

Regards
Matthias Carstens
RME

Re: SRC Questions

I have to admit that I used strong EQ treble boost when I noticed - by chance and without knowing what happened in the first place - there is a difference.

Signal came in via optical, CD source.
Sample rate switching happened through USB connection.


I’ve already reported this here and was told by Matthias that EQ works with internal oversampling anyway.


I have some ideas what happens technically, but don’t want to speculate here.

Not enough sound difference for me worth to use this on a regular base - switching DA-filters has a bigger effect.

Re: SRC Questions

Thank you again Matthias and KaiS for your concise answers. So it seems like a pretty clear case for syncing the ADI-2 Pro with the studio wide sample rate for this situation.

Before long I will move to a Raydat card and the whole studio will move to 96Khz for recording and mixing. Then it seems the transition to 2 x sample rates will be complete for me and having to mixdown with the ADI connected to a second device will not be required.

Kind regards

__________________________
Paul Najar
Jaminajar Music Production
www.jaminajar.com

9 (edited by hasan.ay386 2022-08-06 22:07:45)

Re: SRC Questions

MC wrote:

To illustrate that I measured the filter of the ADI-2 Pro DAC side set to Sharp at 44.1 kHz. Then I activated the SRC and set the sample rate to 88.2 kHz Int.. Yes, the filters of the DAC chip are now completely out of the way as they try to act at 44 kHz - where nothing is happening (no content). But the filter that one might hope to get rid of is still there - this time within the SRC. Not 100% identical (it has its own filter that does not duplicate one of those available in the DAC), but the difference is irrelevant. Point is there will always be such a low filter and there is no reason to believe anything gets better when upsampling.

https://archiv.rme-audio.de/images/adi2pro_da_filter_comparison_dac_src.png

Note this a zoomed view 10 kHz to 30 kHz, and the grey line is at 22.05 kHz.

I wanted to set the internal sampling rate to 96khz and use it with a slow filter with SRC On, so that the fall of the frequency response is above 20khz and for a better impulse response than with sharp filters. So this makes no sense and will not work?

For example, the Cranesong Avocett always upsamples the incoming Digital signal and the upsampled signal goes to the DAC. Is this the same principle in the ADI-2 with SRC on?

10 (edited by KaiS 2022-08-07 08:55:14)

Re: SRC Questions

hasan.ay386 wrote:

I wanted to set the internal sampling rate to 96khz and use it with a slow filter with SRC On, so that the fall of the frequency response is above 20khz and for a better impulse response than with sharp filters. So this makes no sense and will not work?

For example, the Cranesong Avocett always upsamples the incoming Digital signal and the upsampled signal goes to the DAC. Is this the same principle in the ADI-2 with SRC on?

I don’t exactly know how the Cranesong handles this, but yes - and yes, it can make sense (compare to direct by yourself), besides that the filter type doesn’t matter anymore at 96 kHz.

I cannot tell if there is a better sound, when I did this the whole setup was different, not comparable.


Personally, as 95 % of my music is from streaming through USB I’m just using the Slow Filter, straight, as with USB there is no SRC option.

Streaming services replace the original tracks with fake (SRC’ed) 96 kHz versions more and more, which sound slightly inferior to me.
If available I usually prefer the original 44.1 kHz version tracks.