[goodyfresh]

Update: Okay guys so I did alter the title of the thread to better reflect my true intent in starting it, as well as the way the thread has "evolved" over time.
 
To be honest, guys, I never expected this thread to take-off the way it did and become something so long and drawn-out with so much debate, when I first started it back at the end of August!  It has really evolved and grown beyond my expectations and my control.  Certainly interesting, to say the least

 

[RRod]

  @RRod Where oh where did you find that?  And are there more like it?  Links, please!
 
Also, neat, just as I suspected the decay-rate is not constant across all the frequencies.  THIS COULD VERY WELL ACCOUNT FOR THE "COLORATION" THAT PEOPLE HEAR FROM DIFFERENT DAC/AMPS!!!!!!  HHowever, I do not know how to interpret that plot, exaclty.  What is teh signal being input to produce the plot?
 

 
That's an impulse at 44.1kHz interpolated up to 2.25792MHz in SoX (rate -v), then put through a spectrogram (STFT) in R with a window length of 4096 (~0.2ms), Hanning window. If you up the window length you'll get better frequency resolution but you'll lose time resolution, so there's a give-and-take. For instance here's what doubling the window length does:

 
Note how in this view, the content of the pre- and post-ringing is more concentrated in the higher frequencies (and indeed this is all related to the stopband characteristics of the interpolation filter). I'm far from an expert on this stuff, but if you have any measurements you want sent through these kinds of things let me know. Sure wish stv014 was still on

 

[astrostar59]

  @castleofargh
 
I give up, dude.  Seriously.  I give up.  I started this thread in order to ask a simple question:  Are R2R DAC's really as "superior" to DS as so many people claim, and if so, how can we test that and prove it?  ANd it has turned into a debate of science-vs.-subjectivity/faith instead.  Should have known this would frigging happen.

Ha Ha, I love this. Yes R-2R DO sound different. Get some homes for a demo, play the same track at the same volume, and you use your ears. Your brain will then tell you which sounds more accurate. If you look at the ways these 2 methods turn data to voltage, you will not be surprised by that. I can't be bothered to go into it, it is all on the web for you to find.
 
The very reason so many folk are clinging to the technical truth, is they have bought into the over sampling con for the last 20 years. I know, I did just that. Then one day, I thought, why do I not use my 8K DAC anymore, why do I think my 3K turntable (which I sold) sounded better? I then realised the technical stories and bull I was sold was just that, BULL. I went back to the drawing board, used my EARs, and listened to various DACs in situ in my system at the same time. Then I realised I liked R-2R best. I don't care a damb if it is not 'technically correct' or has no filtering, has a 'square wave' or has a dynamic range 100 db instead of 120 db. I am satisfied and happy what my brain is telling me. I know what music sounds like and I have decided an R-2R sounds closer to that trusty than DS. I don't care what anyone else says about that, I don't give two hoots if you all buy 30K Esoteric or dCs stack, don't bother me one bit.
 
If you really want to know more about how flawed the measuring tools are, and how the whole industry convinced itself that over-sampling was necessary, check out the story about TotalDAC. He goes into the flaws of that technology and the measuring gear everyone used as the digital bible, and and why he went back to the drawing board. Others have done that as well such, ditched the oversampling and the brick wall filter.
 
Regardless, if you really want a technical paper to convince you what you have bought is 'great' rather than what you are listening to sounds great, you will not find it, it does not exist....

 

[MacacoDoSom]

I came here to have an answer to this question "R2R/multibit vs Delta-Sigma - Is There A Measurable Scientific Difference That's Audible?" and I think I got it...(in the middle of lot of BS.
There are some measurable differences but they are not audible... like someone said, some people like the butter on one side of the toast, some like it on the other...
as I suspected...
Thank you all...

 

[Currawong]

From the Posting Guidelines:
 

 

DON'T reply If someone makes an off-topic, rude or otherwise inappropriate comment, or a post appears to be trolling or spam.

 Report it by clicking on the red flag and filling in the box explaining what the problem is and let the moderators take care of it. If something is inappropriate or rude, what is the point of giving it more attention by replying to it and/or quoting it?!? If nobody replies to or comments on a trolling or abusive post 100% of the time the person goes away!

 

 

[goodyfresh]

 
Ha Ha, I love this. Yes R-2R DO sound different. Get some homes for a demo, play the same track at the same volume, and you use your ears. Your brain will then tell you which sounds more accurate. If you look at the ways these 2 methods turn data to voltage, you will not be surprised by that. I can't be bothered to go into it, it is all on the web for you to find.
 
The very reason so many folk are clinging to the technical truth, is they have bought into the over sampling con for the last 20 years. I know, I did just that. Then one day, I thought, why do I not use my 8K DAC anymore, why do I think my 3K turntable (which I sold) sounded better? I then realised the technical stories and bull I was sold was just that, BULL. I went back to the drawing board, used my EARs, and listened to various DACs in situ in my system at the same time. Then I realised I liked R-2R best. I don't care a damb if it is not 'technically correct' or has no filtering, has a 'square wave' or has a dynamic range 100 db instead of 120 db. I am satisfied and happy what my brain is telling me. I know what music sounds like and I have decided an R-2R sounds closer to that trusty than DS. I don't care what anyone else says about that, I don't give two hoots if you all buy 30K Esoteric or dCs stack, don't bother me one bit.
 
If you really want to know more about how flawed the measuring tools are, and how the whole industry convinced itself that over-sampling was necessary, check out the story about TotalDAC. He goes into the flaws of that technology and the measuring gear everyone used as the digital bible, and and why he went back to the drawing board. Others have done that as well such, ditched the oversampling and the brick wall filter.
 
Regardless, if you really want a technical paper to convince you what you have bought is 'great' rather than what you are listening to sounds great, you will not find it, it does not exist....

This is. . .wow. . .you're really not understanding the point.  Can you identify which is R-2R and which is DS in blind AB/X testing with better than random-chance rates of accuracy?  If so, how do you know the differences aren't just due to the different analog implementations between two DAC/amps?  Once again, somebody is giong off of subjective impression rather than actual scientific methods of testing, and then try8ing to dress-up their claims in the guise of science in order to seem like they are making a valid point.

You also completely do not understand the theory behind DS, that is obvious to me.  In-theory it is JUST AS CAPABLE AS R-2R of completely and 100% accurately reproducing the original wave-form.  But I guess that for people who don't have a Master's Degree in math (or similar qualitfications) like myself, it is hard to wrap their minds around all those technical details, and so they read that DS "is only approximating the signal by rapidly switching on-and-off one or six bits via upsampling, rather than doing things directly, therefore it is only a crude approximation at best" and just took that at face-value.  Tell me, do you also take the talk of "quantum spirituality" from Deepak Chopra at face-value, as well?  *facepalms, again*  Learn to ACTUALLY understand what the Nyquist Sampling Theorem is saying in the language of Fourier-Analysis, then come back and talk.

 

[]eep]

@castleofargh


I give up, dude.  Seriously.  I give up.  I started this thread in order to ask a simple question:  Are R2R DAC's really as "superior" to DS as so many people claim, and if so, how can we test that and prove it?  ANd it has turned into a debate of science-vs.-subjectivity/faith instead.  Should have known this would frigging happen.

Well, DUDE, you threw in quite a few quarters yourself. Dude.

I mean posting a video of Jack Nicholson shouting: "You can't handle the truth". The real truth, or better irony, is that this gifted actor was playing an arrogant beyond belief SOB killer who was lying through his teeth and was proud of it. By this attitude this whole thread became an invitation to flame and troll. Or in the common language: it became a peeing contest. Or a contest on the longest member.

The answer has come by several times. No pun intended. Or is it? Oh, yeah, time domain. Loops. Pre-ringing, caused by feedbackloops. Or fruit loops. Whatever you prefer to believe.

I haven't even read the last two days worth of reactions, just such a waste of time. I'd rather play Tchaikovsky's 6th symphony. Oh, there's another clue...

 

[goodyfresh]

Well, DUDE, you threw in quite a few quarters yourself. Dude.

I mean posting a video of Jack Nicholson shouting: "You can't handle the truth". The real truth, or better irony, is that this gifted actor was playing an arrogant beyond belief SOB killer who was lying through his teeth and was proud of it. By this attitude this whole thread became an invitation to flame and troll. Or in the common language: it became a peeing contest. Or a contest on the longest member.

The answer has come by several times. No pun intended. Or is it? Oh, yeah, time domain. Loops. Pre-ringing, caused by feedbackloops. Or fruit loops. Whatever you prefer to believe.

I haven't even read the last two days worth of reactions, just such a waste of time. I'd rather play Tchaikovsky's 6th symphony. Oh, there's another clue...

Me posting that clip was uncalled-for, I acknowledge that, which is why I was totally fine with it when Castleofargh deleted the post.
 
You, on the other hand, are coming in here blatantly trolling despite at the same exact time criticizing the act of trolling; if there's one thing I really can't stand, it's hypocrisy like what you are exhibiting here.  You also seem to forget that this was a thread meant to ask a question and one that I started, and as such, I just want some answers from people which I myself can accept.  I am a scientific person who puts my money on the scientific-method 100% of the time in life, whenever I can, and as such the answers I have been hoping for from people to the question I started this thread with are ones that are backed-up sufficiently by actual scientific methods of some kind (blind testing, measurements, etc.) rather than just subjective impressions of "well so-and-so DAC sounds more transparent to me and the bass is tighter, believe my subjective evaluation and statement of that as being a fact despite me just being some random stranger on the internet who is making no actual effort to back up his claims with evidence other than 'this is what I hear.'"  This is the sound-SCIENCE forum, buddy, and as such, it is to be expected that people remain scientific and maintain proper skepticism without ever taking people at-their-word "just because."
 
As such, I have flagged your post as trolling, so that it will probably be removed soon by someone like @castleofargh, as was suggested in a previous post by @Currawong.  I do realize that in that same post he suggested that we not actually respond to trolls.  The only reason I am responding to your bogus post which mocks the pursuit of scientific truth with your mocking tone and your mention of "fruit loops," is to inform you that in the future, I will no longer be the least bit tolerant of blatant trolling in this here thread of mine, nor of posts that attempt to drag the discussion off-topic or derail it by being blatantly non-scientific.  I didn't want to have to do that, because as someone who tries to be scientific I also like to keep an open mind, but this is all seriously starting to drive me nuts and it is becoming a huge waste of my time as well as that of others who just want to actually discuss what real science might be able to do to address these issues.  Any posts in the future that attempt to derail this discussion with claims of "my subjective impressions that so-and-so sounds better than whatchamahoosit trump whatever controlled scientific tests you can perform, because my ears and brain and audio-memory are somehow so much better than an actual controlled experiment of some kind" as well as any which are simply blatant trolling, will be immediately flagged by me for what they are.  This includes, of course, posts like yours here which includes blatantly mocking and sarcastic language, as well as an oh-so-eloquent-and-sophisticated reference to contests involving the size of certain male-specific anatomical features.
 
THe specific original question still has not been definitively answered, nor has a definite means of addressing the question been proposed, despite what you are saying to the contrary.  The stuff you are bringing up (the pre-ringing, decay, whatever) can possibly explain the reported audible differences that exist beteween different DACs/amps which seem to all measure just as "transparent" as one another, and such things should certainly be tested in blind-testing to see if such audible differences really do exist, and if so, measurements need to be developed for quantifying that.  But we have NOT reached a definite consensus on the SPECIFIC question of whether R-2R vs. DS are audibly different when implemented in an identical fashion (nor the issue of HOW one could test that question given the equpiment available today, eg. a Bifrost Multibit vs. a DS Bifrost) and if so (as-in, once again, if that can be demonstrated via blind testing of some sort) what kinds of measurements of the DAC component, specifically, could be used to quantify those audible differences.  Finally, at the end of the day, if such differences can actually be conclusively demonstrated to exist, and measurements can be found that quanitfy those differences, the question finally becomes "which is truly capable of the best transparency and most natural sound reproduction: R2R or DS?"
 
Again:  My own trolling post from a few pages back which you mentioned, is one which I am fine with ahving been deleted, because I realize it was uncalled-for and petty.  And, again, I am the one who started this discussion and want it to be a valid scientific forum to discuss a very real question which can be addressed in a well-controlled scientific fashion, and as such, any more off-topic posts which I see along the lines of "subjective impressions are better" will be flagged as off-topic, and any trolling posts will obviously be flagged as well.

P.S.  You know damn-well how much of a smartass you are being by actually giong ahead and pointing out the technicalities of who Jack Nicholson's character was in that movie and what that quote actually meant in the context of the film.  Seriously.  What the heck, man?  It's just a clip/quote that is often used on the internet to jokingly tell people what it is saying, that "they can't handle the truth."  And here you go getting all technical just to try to prove a point and be a smart-aleck.

 

[Articnoise]

   

 

I understand that you are looking for a simple answer like it is 42 – case closed. But I have to tell you ones again that not all R2R are equally and the same goes for D-S. Even if we only use measurements (which you seems to hold as the truth) all R2R DACs or dac chips do NOT measures equally, very far from it. The same goes for S-D DACs and their dac chips, they do NOT measures equally.

 

The fact is that the better R2R DACs are more similar in measurements (meaning lower crosstalk, lover THD, lower jitter, better squarewaves, better DNR etc.) to modern good DACs that are using hybrid D-S dac chips than older ones that uses older R2R chips.

 

http://www.ti.com/lit/ds/symlink/pcm1704.pdf

http://www.ti.com/lit/ds/symlink/pcm63.pdf

http://www.ti.com/lit/ds/symlink/pcm1792a.pdf

http://www.esstech.com/index.php/products/dac/

 

[astrostar59]

 
This is. . .wow. . .you're really not understanding the point.  Can you identify which is R-2R and which is DS in blind AB/X testing with better than random-chance rates of accuracy?  If so, how do you know the differences aren't just due to the different analog implementations between two DAC/amps?  Once again, somebody is giong off of subjective impression rather than actual scientific methods of testing, and then try8ing to dress-up their claims in the guise of science in order to seem like they are making a valid point.

You also completely do not understand the theory behind DS, that is obvious to me.  In-theory it is JUST AS CAPABLE AS R-2R of completely and 100% accurately reproducing the original wave-form.  But I guess that for people who don't have a Master's Degree in math (or similar qualitfications) like myself, it is hard to wrap their minds around all those technical details, and so they read that DS "is only approximating the signal by rapidly switching on-and-off one or six bits via upsampling, rather than doing things directly, therefore it is only a crude approximation at best" and just took that at face-value.  Tell me, do you also take the talk of "quantum spirituality" from Deepak Chopra at face-value, as well?  *facepalms, again*  Learn to ACTUALLY understand what the Nyquist Sampling Theorem is saying in the language of Fourier-Analysis, then come back and talk.

 
redacted by the FBYofargh, let's try and respect each other so that I don't have to just delete entire posts.
I DO understand the theory of DS, and spent shed loads of money over 20 years because of that (in part). I didn't stop there, i moved forward, and as in medicine there are new advances, even re-visited routes where some question the original theories. Read the TotalDAC story, the Audio Note papers, there are tons of stuff on the web challenging the DS theories. Your best bet, and the only way you will calm down, is to demo some good R-2R DACs against your current DS DAC, and YOU decide. Forget the theories, the measurements, they were flawed anyway.
 
I have something for you to think about. In DS we have a 16 bit signal that is up sampled in the chip to be 18 bit, 24 bit even 32 bit. Now consider, where is this 'new' information coming from? Is it embedded in the original? Is is in a new sub layer. No, it does not exist. 
Now consider the real reason they up sampled in the first place. It was to make it easier to implement a brick wall filter that removed 'artefacts' or 'ringing' in the data. The original 22.05khz of space (half of the 44.1hz) left to do that they say, was close to the human hearing limit. So they only had lets say for an example, 2Khz of space to filter out the 'artefact'. This is where the problems began, and why the whole DS oversampling ethos began and magnified. The better DACs remover there artefacts by other methods, mostly in the analogue domain.
 
There are many building ladder DACs which have NO filtering, and no apodizing or 'guessing' what the gaps in the waveform should be. These ladder DACs convert digital to voltage or 'bit perfect' as many call it with no processing. Some don't even have a c
 
So, we can see there is an 'issue' with DS architecture from day one. Yes, it is cheaper to implement, but that does not stop some manufacturers charging 30K for a top tier DS DAC. There are very good DS DASs about, I have heard some, but i made my choice to go R-2R. You make your choice, I have no issue with that. What I have an issue with is you are clinging to the technical theories to justify that. I try to put that to one side, and mark performance on what I hear, and how it makes me real about the music. It is a personal thing, thus we will never agree..... you read the tech specs, I will stick to what I hear.

 

[OddE]

 
You are a fool my friend. I DO understand the theory of DS, and spent shed loads of money over 20 years because of that (in part).
 
(...)
 
I have something for you to think about. In DS we have a 16 bit signal that is up sampled in the chip to be 18 bit, 24 bit even 32 bit. Now consider, where is this 'new' information coming from? Is it embedded in the original? Is is in a new sub layer. No, it does not exist. 
 
(...)
 
you read the tech specs, I will stick to what I hear.

 
-So, as you DO understand the theory, you DO understand that 'upsampling' does not increase the bit depth, and also that increasing the bit depth as you are alluding to does not add new information, it simply provides more headroom for you to manipulate the data stream? (Now, oversampling, on the other hand, leaves the bit depth intact but interpolates new values inbetween the existing ones.)
 
Besides, this is getting old. This forum more or less in unison suggest that you use your ears - not your other senses. Still you manage to make it appear that you are the one using your ears, not the rest of us...

 

[castleofargh]

I take a small 11hours nap(^_^) an here is what I come back to. I believe most of us can agree currawong did the right thing that I failed to do.
ok castleofargh sucks at diplomacy could be the other title of this thread. but my now ancient life as moderator on gaming forums showed that I can be a very realistic dictator. I'm counting on you all to tell me when one should become the other. the line is still blurred in my mind.
 
 
 
Quote:

 

   

 

I understand that you are looking for a simple answer like it is 42 – case closed. But I have to tell you ones again that not all R2R are equally and the same goes for D-S. Even if we only use measurements (which you seems to hold as the truth) all R2R DACs or dac chips do NOT measures equally, very far from it. The same goes for S-D DACs and their dac chips, they do NOT measures equally.

 

The fact is that the better R2R DACs are more similar in measurements (meaning lower crosstalk, lover THD, lower jitter, better squarewaves, better DNR etc.) to modern good DACs that are using hybrid D-S dac chips than older ones that uses older R2R chips.

 

http://www.ti.com/lit/ds/symlink/pcm1704.pdf

http://www.ti.com/lit/ds/symlink/pcm63.pdf

http://www.ti.com/lit/ds/symlink/pcm1792a.pdf

http://www.esstech.com/index.php/products/dac/

you're very right, clearly one of the voices of reason in the topic.
measurements are the very best, I have no doubt about that, but that doesn't mean all measurements give real life values, and that's why knowing how the measures are done is as important as knowing how to read them. when I see the measurement of an amplifier into 10kohm and nominal output, it would be silly to expect the same when I plug a 16ohm IEM in it to listen at comfortable loudness. almost every specs will fall.
but a DAC measured with 10kohm, that's very close from real life usage. all amps will have a several thousand ohm input. and about the max output, well as long as we don't attenuate the volume digitally on the computer, we'll also be very close. so I do trust measurements for a DAC to give a pret realistic vision of the signal in real life usage.
 
but as you say, we do get DACs with pretty great measurements for both techs(thanks to the engineers doing a nice implementation job). as Baldr said, usually the way to get the best signal out of a sigma delta chip is to follow the manufacturer's guideline to the letter. does that mean it's bad? I don't think so, just that it's cheap and require less R&D.
but still, we didn't answer much. can we make using both techs, 2 DACs that exceed human thresholds in resolution? my own experience would push me to say yes, but then you get Astrostar saying no and that R2R is better(at least to his ears without serious controls).
 
unless we can get a clear answer, a demonstrated one, the rest is a futile exercise sadly. "I got better distortions thanks to linearity", "yes but I get lower noise". nobody knows how audible are those differences, so we become religions, thinking the phase is super important while being unable to pass a blind test. or we decide that noise is always audible and should be at -200db when we actually fail to notice a dithered sound at -90db.  if it's science just to use a rocks to fight our cult wars, it's a sad waste of science. too often that's exactly what happens and most likely one of the reasons why headfi went all "no blind test talks" on the rest of the forum.
what I would like to know is if we can get transparency with both techs? or if, as many people seem to believe, R2R sounds different. not in general, but with some of the best measuring DACs of both kinds. the question being really to know if we can achieve transparency. not at all to say that all DACs are transparent, or that any crap with a R2R resistor ladder will have those characteristics. I'm sure some people will interpret it as such because audiophiles love nothing more than to turn a "it happened once" into a godly rule. but the more informed and reasonable people, could take the information for what it is. and that would be something like:
1/ we can get transparent at the DAC with both techs
or 2/ one behaves better because the hard limit of the component is this and that and so the very ultimate DAC should use XXXXX tech.
or 3/ the limiting factor of the DAC is the analog part and R2R or SD don't really matter on their own.
I would be ok with any of the answers for that matter.
 
on a money per performance standpoint we already very much have our answer, sigma delta gives the best value. that is a manufacturing fact. so we're not totally in the dark. but I sure would love to know if investing in a great R2R is more than just deciding to use the expensive stuff for the sake of it being expensive and becoming rare.
 on a personal level, I would take any and all factual information, be it anecdotal on a given model, or about the technology or the difficulties of implementation. I like to learn, that's science for me.
 
for the ESS chips, I find the 2 videos done at RMAF to be full of interesting information. probably not all it to take at face value because the guy is still there to tell how great his chip is, but I learned a lot when those vids came out. https://www.youtube.com/watch?v=8Mn5PrnZV-k  and https://www.youtube.com/watch?v=JYjHKv2_OqQ
 of course it doesn't tell much about what R2R can do. having so little choice in the chips does simplify the questions about products variations.

 

[arnyk]

   
I have something for you to think about. In DS we have a 16 bit signal that is up sampled in the chip to be 18 bit, 24 bit even 32 bit. Now consider, where is this 'new' information coming from? Is it embedded in the original? Is is in a new sub layer. No, it does not exist. 
Now consider the real reason they up sampled in the first place. It was to make it easier to implement a brick wall filter that removed 'artefacts' or 'ringing' in the data. The original 22.05khz of space (half of the 44.1hz) left to do that they say, was close to the human hearing limit. So they only had lets say for an example, 2Khz of space to filter out the 'artefact'. This is where the problems began, and why the whole DS oversampling ethos began and magnified. The better DACs remover there artefacts by other methods, mostly in the analogue domain.
 
 

Wow, what a collection of misapprehensions!
 
When data is upsampled, no new data is added. Well obviously samples are added, but the added samples are zeroes, so no new data as such is added.
 
Why is the signal upsampled? Yes, it is upsampled to facilitate digital filtering, but the digital filtering is not gratuitous. It is part of the design of a proper DAC. A proper DAC has a brick wall filter, and any DAC that lacks one is improper or broken. Call it what you want, but it is not a proper DAC. It is a broken DAC. Its like a 4 wheel automobile with the rear wheels missing. The back bumper is dragging on the ground.
 
The brick wall filter is not there to remove ringing. In fact it is usually the cause of ringiing.  So why add something that causes ringing?  The reason the brick wall filter is there is that a larger more important purpose needs to be served.  The purpose that needs to be served is that the DAC is supposed to only output signals in its defined band of operation, such as 20-20 KHz. Without the brick wall filter, the incomplete DAC will produce signals that are outside that defined band, and that may or may not cause other problems. Do it right and there are in general no problems no matter what. 
 
Does it matter whether these spurious signals are removed in the analog domain or the digital domain? If you are a fan of removing spurious signals in the analog domain, take heart because proper DACs with digital filters still have analog filters that remove spurious responses in the analog domain. It is just that the analog filters operate at a far high frequency where their design and operation is vastly less critical so they can be relatively simple.
 
The removal of spurious responses in the digital domain is just a refinement to the process that allows us to further exploit the benefits of being in the digital domain in the first place. If you like throwing away benefits for no reason, then by all means avoid digital filtering!  But, it will cost lots of money and provide no audible benefit.  You pays your money and you makes your choice.
 
well enough explaining the true story for now!

 

[astrostar59]

Quote:

  Wow, what a collection of misapprehensions!
 
When data is upsampled, no new data is added. Well obviously samples are added, but the added samples are zeroes, so no new data as such is added.
 
Why is the signal upsampled? Yes, it is upsampled to facilitate digital filtering, but the digital filtering is not gratuitous. It is part of the design of a proper DAC. A proper DAC has a brick wall filter, and any DAC that lacks one is improper or broken. Call it what you want, but it is not a proper DAC. It is a broken DAC. Its like a 4 wheel automobile with the rear wheels missing. The back bumper is dragging on the ground.
 
The brick wall filter is not there to remove ringing. In fact it is usually the cause of ringiing.  So why add something that causes ringing?  The reason the brick wall filter is there is that a larger more important purpose needs to be served.  The purpose that needs to be served is that the DAC is supposed to only output signals in its defined band of operation, such as 20-20 KHz. Without the brick wall filter, the incomplete DAC will produce signals that are outside that defined band, and that may or may not cause other problems. Do it right and there are in general no problems no matter what. 
 
Does it matter whether these spurious signals are removed in the analog domain or the digital domain? If you are a fan of removing spurious signals in the analog domain, take heart because proper DACs with digital filters still have analog filters that remove spurious responses in the analog domain. It is just that the analog filters operate at a far high frequency where their design and operation is vastly less critical so they can be relatively simple.
 
The removal of spurious responses in the digital domain is just a refinement to the process that allows us to further exploit the benefits of being in the digital domain in the first place. If you like throwing away benefits for no reason, then by all means avoid digital filtering!  But, it will cost lots of money and provide no audible benefit.  You pays your money and you makes your choice.
 
well enough explaining the true story for now!

http://www.audionote.co.uk/articles/reviews/DAC-5_June_2000.pdf

 

[arnyk]

  http://www.audionote.co.uk/articles/reviews/DAC-5_June_2000.pdf

 
That was 15 years ago, and its a whole article not a reasoned response to my post.  The guy had some hardware to sell and said whatever he thinks he must. Next!
 
What is your response to a thoughtful response to your post?