Topic: Impulse response of ADI-2 DAC


     I'm relatively new in this region and trying to understand problems with pre and post-ringing, impulse response and some other artifacts in sound produced by DAC. My ears are quite sensitive and I like normal real-like sound :-) In the past I had some top end CD players from Pioneer and Denon and I liked their sound. I don't care some noise, but I care natural character of the sound (impulse)
Now I have expensive player with ESS Sabre 9038PRO and I don't like it very much :-(

Today I ordered ADI-2 DAC and I will test it in few days and I hope I will like it, because I'm looking for one great solution for D/A conversion, headphone amp, pre-amp with XLR output and remote of course :-) DSP and other features are great at this price...
And I'm tired from temporary Hi-End audio world full of marketing and snake oils.

And now my question: How can I understand of impulse response of this new Denon DCD 2500NE with Alpha processing?
Here is the link with measurements: … w_Test.pdf

And how to compare this perfect impulse with your unit? For me, it seems, that Denon must sound better, but I'm not sure if I'm correct and if some other parameters matters more. I don't have Denon home and I know that it is no versatile piece of gear, I don't care for money too much, but I care about my ears and natural sound. And I also don't want to have full house of equipment. :-)

Can you please comment this question and give me some advice for setting ADI-2 DAC with MAC and Audirvana+ (also new thing for me) and playing files from MAC (FLAC, WAW, ALAC and Tidal stream) for best sound possible? If I should upsample 44,1 files or not, if I should care about USB cables (length - is 3m too much?, isolation,...) Should I care about "Jitter" or how to set clock in RME unit, or leave it in default setting?

Thanks beforehand for help.


Re: Impulse response of ADI-2 DAC

If you have the ADI , don´t forget to try all the filter options, to see which you prefer. OTH it is difficult to know why you liked the Denon. Could be impulse or anything else. I doubt if the graphs are at the same resolution so I would not compare them. RME graphs are  for showing the effect of the different filter settings.

Don´t upsample as upsampling causes artefacts too.
USB is irrelevant as long as it works.
If you play from mac or PC clock will be internal, which is perfect.

Vincent, Amsterdam
HDSP9652+ADI-8AE  2X HDSP9632
Cubase pro10

Re: Impulse response of ADI-2 DAC

I know that I can change 5 filters, My Sabre player offers even more and no one is perfect. I don't understand why we have so many options for filtering and everyone has some problems. Why not one perfect?

Re: Impulse response of ADI-2 DAC

Because of the steep filtering needed for anti aliasing. For 44k sampling and  up to 20k audio you need to filter all audio in a range from 20k-to 22k to silence. That is steep! You need to understand how filtering works to know it is always a compromise. I don´t understand but I trust them.
Personally, as a musician, I am in awe, how good recorded audio sounds. For me it is up to the point that what goes in (record) comes out the same. That has not always been the case, having started on analogue tape and vinyl. On vinyl filtering was needed much much more and people do seem to like it.
Plus maybe, your taste in audio, must coincide with that of the mix engineer and producer. I would guess that if you had the audio files, that would be of much more influence then any dac, if you could mix and eq to your taste. No master of any music is not already a compromise.

Vincent, Amsterdam
HDSP9652+ADI-8AE  2X HDSP9632
Cubase pro10

Re: Impulse response of ADI-2 DAC

I disagree Vinark,

I don't trust easy, I'm not a believer. And I know that we need to filter audio above 1/2 of sample rate. And because of that I enclosed measurements data from Denon, which also filter all audio above 1/2 of sample rate and has no pre or post-ringing, has perfect rectangle and impulse response, no intermodulation etc., etc..... And I'm just asking PRO people from RME for explanation why Denon behaves this way and ADI-2 DAC different way and how it influence the sound.

I'm not looking for the magic, just want natural correct sound, where strings sounds like strings and singers "S" like "S" and not like "tSSSSSsssss" and I don't want to "hear" any other artifacts even in "inaudible" spectrum. I think, that somebody can feel and hear differences in sound, when one is clear and other has added strong distortion above 20kHz.

And may be I don't understand you correctly, because of my English... But I don't think, that any master is not compromise. I think, that many modern masters and remasters of great old releases are disaster. There is no dynamic range, no quiet passages, most of peaks are cut and everything is around full 0dB, but it is another sad topic for another debate. We have all great technical solutions and we are producing garbage good maybe for cellphones and radio...


Re: Impulse response of ADI-2 DAC

I am not familiar with that magazine and its test methods. But I can see that the square wave is very bandwidth limited (skewed edges) and won't look different on an ADI. See also here: … s-dac.html

The impulse response looks like Slow or NOS. Doesn't matter much as you won't hear any ringing anyway, or does your music sources have significan't 22 kHz content, and you are able to hear that frequency?

Matthias Carstens

Re: Impulse response of ADI-2 DAC

Hello MC,

    thanks for reaction. I know archimago too :-) and I saw all measurements. But I'm still not sure, how to understand it.

For example here is another measurement from same magazine and same guy and now it is very expensive and "famous" Yamaha with Sabre chip. And here the impulse don't look so good. And Steve Holding said, that Denon is a stellar piece of gear.

Look at: … w_test.pdf

And I also don't understand why Denon's impulse looks like slow or NOS in that case, when there is no intermodulation like is common in slow and NOS filters. I see it in archimago graphs of ADI-2 too. This all confuses me totally. They measure 19 and 20kHz and slow and NOS filters makes big intermodulation on 24 and 25kHz, am I right?
Of course my music has no significant 22kHz content. I just want to understand how it works and why to spend some money.
I like ADI-2 DAC's features and most parameters very much and so I ordered one and I hope it will sound good, but I'm still afraid a little bit because when I listened OPPO UDP-205 for example I heard some strange artifacts in very high frequencies and unpleasant sibilants. It was heard in both through amp and speakers and also with PRO headphones directly from OPPO DAC.
May be bad source and some masters in combination with extremely detailed OPPO. May be I need some ALPHA Processing from DENON. Who knows? Do you know the "magic" of Alpha Processing from Denon?

I'm not an electrical engineer and I don't understand all problematic in deep details. I just thought that in these days is possible to achieve precise impulse response with no significant side effects. And I want to enjoy music without stress and harshness. And may be I will achieve it with your DAC :-) Will see in next days...



Re: Impulse response of ADI-2 DAC

i prefer to set NOS for more "easy touch of music" and don't care about non-filtered ultrasonic noise
maybe its some kind of euphony effect but its works and i happy with my adi