Review and Measurements of RME ADI-2 Pro (comparison to ADI-2 DAC)

[JohnPM]

the point is that specific "signature" of the chip will now "draw" the graphs of measurements of other equipment ((

It should be very consistent measurement to measurement, just calibrate it out as part of your reference response so it is subtracted, leaving the response of whatever you are trying to measure.

 

[Jimster480]

@Thomas savage

I understand your "we don't know anything" attitude when there's absence of solid facts. But in this case we do have facts.

What drew my attention was this quote from member @Dro :

"According to this, there are no differences between the Pro and Pro FS besides Auto Dark and new clock".
Source: https://www.audiosciencereview.com/...-pro-comparison-to-adi-2-dac.2682/#post-75929

According to RME: "I am surprised that Thomann treats this as totally new product, when there are only two smaller (minor) changes. For us it is a slightly updated ADI-2 Pro".
Source: https://www.forum.rme-audio.de/viewtopic.php?pid=129982#p129982

So I am not speculating here. I am basing my reasoning on RME's own words.

And because "fs" is featured on the front of the RME box, I think that may be the most important update of the two. A third possible change is the somewhat altered PCB board, but RME doesn't say that this change is material for sound or measurements.

In other words, we have pretty good reason to speculate that the femto clock is the most significant driver behind better measurements.

Interestingly, it seems like lots of "objectivists" are not very interested in clocks. Despite for example Paul Miller documenting a clock's contribution to significantly better performance in this review:

https://mutec-net.com/downloads/manuals/MUTEC_MC-3plusUSB_-_HFN.pdf

See the middle graph on page 2 of that review. It's the Oppo BDP-105D with and without reclocking.

According to Geoff Martin, "[t]hese days the weakest links in a digital audio signal path are typically in the signal processing software or the clocking of the devices in the audio chain". Source: http://www.tonmeister.ca/wordpress/2018/03/25/typical-errors-in-digital-audio-wrapping-up/

I think that statement is worth spending some time on.

I can understand Clocks being a source of jitter especially in modern products where there are often many devices connected at once and data flowing in all directions.
Nevermind the abundance of products themselves, if clocks don't match up then it will cause jitter.

 

[DonH56]

Hmmm... Normally a PLL is used so the clock and data are in synch for each device, and I think the majority of DACs these days run asynchronously so input clock jitter is not passed on to the output. Different clock frequencies will cause buffer over- and under-runs but not jitter, unless cycle slips cause problems. They can cause data loss, however, and that is usually a Bad Thing.

 

[Jimster480]

Hmmm... Normally a PLL is used so the clock and data are in synch for each device, and I think the majority of DACs these days run asynchronously so input clock jitter is not passed on to the output. Different clock frequencies will cause buffer over- and under-runs but not jitter, unless cycle slips cause problems. They can cause data loss, however, and that is usually a Bad Thing.

Well wouldn't that fall into jitter or be interpreted as such by the analyzer?

 

[DonH56]

What would be interpreted as jitter and by what analyzer? If you are looking at the output using an audio analyzer then data loss will add distortion and/or raise the noise floor. If you are using a signal analyzer it should separate random from deterministic jitter, and from actual data loss, though a device that does not "know" the data might not know when a bit is captured wrongly. A signal analyzer (dedicated or DSO package) can also show clock variation by various means (we use them to check the SSC - spread spectrum clock - profile, for example). An RF analyzer will capture phase noise and integrate it to produce a jitter number (and may or may not distinguish random from deterministic). I guess for me the short answer is "it depends".

 

[Jimster480]

What would be interpreted as jitter and by what analyzer? If you are looking at the output using an audio analyzer then data loss will add distortion and/or raise the noise floor. If you are using a signal analyzer it should separate random from deterministic jitter, and from actual data loss, though a device that does not "know" the data might not know when a bit is captured wrongly. A signal analyzer (dedicated or DSO package) can also show clock variation by various means (we use them to check the SSC - spread spectrum clock - profile, for example). An RF analyzer will capture phase noise and integrate it to produce a jitter number (and may or may not distinguish random from deterministic). I guess for me the short answer is "it depends".

I am talking about an analog external analyzer like a Dscope.
I think it would depend on the type of data corruption, I have seen data corruption happen over USB even onto USB flash drives. While it has only happened a few times in the last 14 years of me using flash drives.... And I know in external video devices that jitter is interpreted differently.... I have a software for my tablet that makes it into an extra screen and jitter can get quite interesting with the screen itself flickering, losing quality, disconnecting or color/data artifacts. So considering the broad number of outcomes with video, if you apply the same to audio I think it would safe to say that there could be jitter determined in the analog output specifically from data communication failures due to clocking.

 

[watchnerd]

At these extremely low levels, isn't this all rather like counting angels on a pinhead?

I've used the non-FS Pro for recording and can't hear any audible artifacts...I hit the noise floor of the rest of the chain first. Same thing for playback using the DAC.

I don't like the UI, but overall I still find it better than my previous reference interface, an Apollo Twin Duo.

 

[Jimster480]

At these extremely low levels, isn't this all rather like counting angels on a pinhead?

I've used the non-FS Pro for recording and can't hear any audible artifacts...I hit the noise floor of the rest of the chain first. Same thing for playback using the DAC.

I don't like the UI, but overall I still find it better than my previous reference interface, an Apollo Twin Duo.

Basically you are right, none of this should be audible. But its all about being objectively better.

 

[svart-hvitt]

Basically you are right, none of this should be audible. But its all about being objectively better.

At one point «objectively better» means «better for idiots».

Part rant and part reflection on which part of the chain we would better focus on.

 

[amirm]

Well, in my case I need a pristine reference to test against. If something generates random jitter, I like to see it and not doubt that it is due to my DAC.

FYI, RME USA confirmed that the new clock in FS fixes that random jitter I am seeing.

 

[Sythrix]

Well, in my case I need a pristine reference to test against. If something generates random jitter, I like to see it and not doubt that it is due to my DAC.

FYI, RME USA confirmed that the new clock in FS fixes that random jitter I am seeing.

That's great, but are they going to let you replace it with the FS?

 

[amirm]

Unfortunately they made no such offer.

 

[svart-hvitt]

Well, in my case I need a pristine reference to test against. If something generates random jitter, I like to see it and not doubt that it is due to my DAC.

FYI, RME USA confirmed that the new clock in FS fixes that random jitter I am seeing.

Agree.

Measurement device and adequate playback gear are not always the same.

And I take my hat off for engineers who go the extra mile in terms of measurements.

 

[svart-hvitt]

Unfortunately they made no such offer.

Seems like you got yourself a nice playback gear then

 

[Sythrix]

Unfortunately they made no such offer.

Ridiculous. I would sell the pro for the DAC version unless the ADC portion turns out to be phenomenal.

 

[amirm]

Yeh, the ADC part is what is keeping it on my bench right now. I plan to test that soon.

I am wondering if RME got upset at me with our discussion of headphone performance (and driver issue). Regardless, I did expect them to want me to have their best product given the use it is getting on this site.

 

[watchnerd]

Basically you are right, none of this should be audible. But its all about being objectively better.

At one point «objectively better» means «better for idiots».

Part rant and part reflection on which part of the chain we would better focus on.

As an amateur recorder / mixer, I guess my attitude is probably closer to that of professionals:

It's a tool.

The difference between the FS and non-FS version isn't apparent until you hit like -120 dB, which won't make any difference in my recordings / mixes, and I'm far better off worrying about microphones, the mix itself, and calibrating my playback monitors / headphones.

Being a "gear slut" can have pretty serious diminishing returns.

 

[Jimster480]

As an amateur recorder / mixer, I guess my attitude is probably closer to that of professionals:

It's a tool.

The difference between the FS and non-FS version isn't apparent until you hit like -120 dB, which won't make any difference in my recordings / mixes, and I'm far better off worrying about microphones, the mix itself, and calibrating my playback monitors / headphones.

Being a "gear slut" can have pretty serious diminishing returns.

That's how it always is. I am a software developer and I am the same with my computers.
I get what is great for my work and handles my workload, but I won't spend money for something I won't use.

 

[watchnerd]

That's how it always is. I am a software developer and I am the same with my computers.
I get what is great for my work and handles my workload, but I won't spend money for something I won't use.

Which is why on this "objectivist" site it would be good to remind ourselves what actually matters and makes a difference to the sound.

I feel like sometimes people chase measurements for the sake of epeen.

So many of the DACs measured here are more than "good enough", sometimes it feels like it may be a disservice to the naive reader to spend so much time obsessing over sub-audible minutiae.

It's cool that we all benefit from Amir's willingness to make full use of his AP, but measuring competently designed DACS these days does feel like a bit of a bikeshedding exercise when compared to things that really move the audible needle, like DSP.

 

[AudioQuality777]

Well, in my case I need a pristine reference to test against. If something generates random jitter, I like to see it and not doubt that it is due to my DAC.

FYI, RME USA confirmed that the new clock in FS fixes that random jitter I am seeing.

Hi amirm. Tell me about the graph of jitter. In numbers, how many pico, nano, femto seconds?