Topic: ADI-2 Pro - AD/DA Filter Discussion

Hi,

I recently got the ADI-2 Pro and I am enjoying the superb sound quality a lot!
However, I would love to learn more about the Filter options and how people use those.
Usually I use the Sharp SD for DA because it's so precise and detailed. Why would somebody prefer the non SD version?
Then there is the slow filter option for the AD. Is this meant to be used for higher samplerates (because of the audible roll of in 44.1)?
Other than those questions I would love to hear howe people use their ADI-2 Pro regarding the filter settings!

Regards,

Michael

2 (edited by attilafaravelli 2017-01-13 02:37:22)

Re: ADI-2 Pro - AD/DA Filter Discussion

Hey Michael,
wondering the exact same as you do. I read everything I could find about it, there's even an interview with the Japanese designer of the ADI-2 Pro AD-DA's chips which delves deep into this same topic, but I still don't get it: first of all, and this will sound like a stupid question I know, but why is a filter needed in a converter? Could someone dare to explain it to me in plain words? Understanding this would help, I don't think the graphics on the ADI-2 Pro manual with all the different filter's curves convey this very basic information at all. I guess many people will wonder the same, otherwise just blame my ignorance..

I know from using linear or minimal phase equalizer plugins the differences in transients shaping from the 2, linear phase ones introducing some very subtle smoothing on some setttings (HP expecially). Is it the something similar with the ADI-2 Pro AD DA filters? I can hear that the sharp filters on the RME sound crisper and the slow ones lack a tiny bit of very high freqs.

I've been using the RME for listening to my own stuff, which is just tons of stereo unprocessed field recordings. I record with Sennheiser omni mics (they are more like baromethers than mics..) and know my sounds very well. As soon as I started listening to them with the ADI-2 Pro I discovered stuff I didn't know it was there. I'm enthusiast about how this little device sounds, I probably had heard a similar level of detail when doing the mastering of my stuff at a colleague's studio with Prim DAs.
BTW, even if I love it a lot, I don't consider the RME a neutral sounding device. I perfectly know the flaws and character in my field recording setup, Sennheiser MKH 8020's tend to sound a little boomy and dark, they pick up tons of low-mids and that's the reason I love them, they just enhance the rough organic side of a sound. I also know from years of experience that Sound Devices recorders, which I use, are tuned toward mid frequencies because they are mainly used and designed for dialog, the AD converters in their machines are no exception to this (when I tried to use my 633 for listening to music I was very disappointed to hear this subtle but clear focus on the mids).

Still, when listening to my recordings with the RME everything sounds more crisp and detailed, which is perfect for me and I wouldn't go back.. but I'd dare saying that it has its own sound character  which is oriented toward ultra high definition. I feel like there's a slight enhancement to the signal, like applying the Kush clariphonic but of course much much more subtle and natural sounding with the RME. Long ago I had the same kind of feeling when demoing some so called hi fi player apps for the mac, 'better' substitutes to Itunes, like Amarra etc.. They say (their developers) that their sound file reading gets rid of all the interferences from other processings going on in the machine and stuff like that but in the end they don't fool anybody with good hears.. it's clearly at play some enhancing algorithm which explains why all of these apps sound very different. I'm not saying that the RME is fooling me with enhancers or so, and the kind of improvement I hear from this device is worth every last bit of data.. but I wouldn't say it's a neutral sounding processor. That's why I'm very interested in understanding the filter options, given its NON neutrality..I don't think any AD DA will ever be transparent, even just because there's some analog components in them.. leaving apart the chips mess. I'd like to better be able to 'play' with the filter options and to do so I need to understand them better.

The very last nerdy check I did was this, I brought the RME into the field, I used an iphone with the camera connection kit and a portable 12 v battery. I plugged my mics into an SQN mixer I just got, it's an all transformers rather heavy indeed portable preamp from the 90s, one of the very top sounding coloured portable mixer around along with Nagra's and Cooper Sound's. I then captured the balanced out from the SQN into the RME, recording the digital sound with the Apogee Metarecorder app on the iphone. Again, the results are excellent, I'm not complaining.. but well, the sound coming out from the headphone amps in the SQN was one thing, and the one coming out from the RME was a completely different thing.. I know the headphone amp is different.. but come on, I'm working with sound since years, mostly on some very subtly textured low level sounds.. I sometimes use a Sound Devices USB Pre 2, which allows to monitor both the analog input and the signal after the conversion and the difference between the 2 is rather negligible. The 'converted' SQN mixer's sound sounds like a HD version of it, which is just great but I wouldn't call the RME a neutral device..

3

Re: ADI-2 Pro - AD/DA Filter Discussion

I see it the other way round. The ADI-2 Pro is not enhancing anything - the others are just damping/hiding it a bit.

Regarding the filters: it is indeed not our task to explain basic knowledge and techniques of digital audio. Every DAC has a filter, and the web is full of explanations how DACs work and how the oversampling filters in those operate.

The difference here is that you not only have one fixed filter, or two (as it was mostly the case so far, one low latency, one higher latency, and the higher latency is not even selectable in most audio interfaces, because everyone craves for lower latency only). But in the ADI-2 Pro offering all filters makes sense, as there are lots of applications for it where latency doesn't matter.

The sound differences between these filters are subtle, definitely not night and day. Some people will not hear any difference at all. In the studio I would not use the ones that negatively impact frequency response, for obvious reasons. That leaves you with SD Sharp and Sharp. As you can see in the DSO pictures you then have the choice between pure post ringing (default) and reduced ringing, but both pre and post. Choose whatever you like!

The typical HiFi listener loves perfect transients. He will gladly accept reduced treble and ultrasonic noise to have that. NOS is therefore very popular among those customers.

Regards
Matthias Carstens
RME

4 (edited by ramses 2017-01-13 08:16:19)

Re: ADI-2 Pro - AD/DA Filter Discussion

MC> I see it the other way round. The ADI-2 Pro is not enhancing anything - the others are just damping/hiding it a bit.

Fully agree. I think that you are a very good "listener" and know your material very well. But at the end you are simply used to the presentation and limitations of your old equipment.

In terms of Quality of ADI-2 in general: I compared the ADI-2 Pro to am Accuphase E-600 Class A amplifier with build-in D/A converter module (DA-40). It was difficult to hear differences between the ADI-2 Pro and the DA-40.

In both cases you hear a detailed room with the instruments on their positions. For my ears the ADI-2 Pro sounded slightly more detailed in the default filter mode "SD sharp". Its not "black and white" as MC tells, only subtile changes and required many comparisons to find something in the sound material where you think there is a slight difference. What I want to tell It was really not easy to find differences.

When I used NOS to compare ADI-2 Pro and DA-40 I had the feeling it sounded more or less the same.
Maybe it requires other Music Material to be able to recognize the differences better maybe also other listening volumes.

In terms of DA-filters, simply enjoy that they are there, maybe in the future you will have a use case for this.

At the end you will find out that the ADI-2 Pro is a really high end reference class DAC. Use the default filter for best presentation of music material. The other DA filter are there, but I would ignore them for now if it doesnt bring to you an evident benefit.

Also with an HiFi Amplifier you need to take pragmatic decisions. Do I want to use Loudness, Bass or Treble ? Me usually not.
But .. the dynamic Loudness function of the ADI-2 Pro.I will definitively miss with any HiFi Amp wink

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: ADI-2 Pro - AD/DA Filter Discussion

Hey MC and Ramses, thanks for expressing your opinion! You probably are right when you say that I'm used to the limitations or anyway lower definition in the AD DA section of my old equipment.

As a less technical consideration I resist in my opinion that there's specific choices made by specific people when designing a chip like the one used in the ADI-2 Pro, or when implementing it. The interview with the Japanese crew is indeed very interesting, there's a lot more than specs going on, listening sessions, almost esoteric briefings:) Not only we don't hear just specs.. nor the people who design stuff only have hears for specs.. also, specs themselves must be so interrelated that at some point a choice has to be made.
To my hears, and I can be wrong of course, I feel like with the ADI-2 Pro there's the specific intention to show the high definition of a sound and not so much its organic qualities, but again my experience with other high end Dacs is very limited. Also, I really like the RME for my stuff, which is what finally matters:)

Re: ADI-2 Pro - AD/DA Filter Discussion

Can you pls explain the difference between "high definition" and "organic qualities" ?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: ADI-2 Pro - AD/DA Filter Discussion

I am still wondering about the slow AD Filter...
If you are doing an analog roundtrip I guess you would'nt want that because of the HF Rolloff (if you are capturing at 44.1), but I wonder if it could be used to tame harsh Instruments/Microphones on the way in.

8

Re: ADI-2 Pro - AD/DA Filter Discussion

I think the EQ would be a better way to do that. Actually I will try to examine the input filter's impulse response and phase to give more information why and when it could make sense. After NAMM, that is.

Regards
Matthias Carstens
RME

Re: ADI-2 Pro - AD/DA Filter Discussion

MC wrote:

I think the EQ would be a better way to do that. Actually I will try to examine the input filter's impulse response and phase to give more information why and when it could make sense. After NAMM, that is.

That's great news! Thank you for your efforts and have a good time at NAMM!

10

Re: ADI-2 Pro - AD/DA Filter Discussion

NAMM was phantastic, and now back in Germany I measured the impulse response behavior of the AD filters Slow and Fast (which are Short Delay Sharp and Short Delay Slow at this time). The new manuals version 1.5 include a new chapter about it. They are available for downlad here:

https://archiv.rme-audio.de/download/adi2pro_d.pdf

https://archiv.rme-audio.de/download/adi2pro_e.pdf

The topic is quite interesting and allows to raise the audio quality of the whole unit even more. That's why we will add two more filters with the next firmware update, bringing AD to the same filter functionality as the DA side (except for NOS, which is not possible on AD).

Regards
Matthias Carstens
RME

Re: ADI-2 Pro - AD/DA Filter Discussion

See chapter 34.10.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: ADI-2 Pro - AD/DA Filter Discussion

MC wrote:

NAMM was phantastic, and now back in Germany I measured the impulse response behavior of the AD filters Slow and Fast (which are Short Delay Sharp and Short Delay Slow at this time). The new manuals version 1.5 include a new chapter about it. They are available for downlad here:

https://archiv.rme-audio.de/download/adi2pro_d.pdf

https://archiv.rme-audio.de/download/adi2pro_e.pdf

The topic is quite interesting and allows to raise the audio quality of the whole unit even more. That's why we will add two more filters with the next firmware update, bringing AD to the same filter functionality as the DA side (except for NOS, which is not possible on AD).

That's great to hear! I look forward to test out the SD Filter against the non SD!