Upsampling DACS: Take the Pepsi Challenge

Gthirteen, you are more than welcome. Wonderful thing about this forum is that, with the collective knowledge and experience to draw upon, greater understanding will result in the truth. In my line of work, we use quite a bit of very sophisticated algorithm development. MUCH more sophisticated than that found in audio. But it is really hard to make digital theory easily digestible and therefore hard to bring it to a point where it makes sense to everybody. I think the author did a magnificent job in his explanation. Coming around full circle, you can see why Carl was right - digital has the infinite capability to produce more dynamic and "lifelike" quality of music than analog. But, as always, the science lags behind the enabling technology. Therefore, we will have to wait about 5 years, by my estimate, to begin to fully realize the promise of the CD. Biggest thing to remember is that the science of hearing and how the brain distinguishes sounds, transients, harmonics, etc. is really not well understood at all. Therefore, you and I hear (and "understand" music) differently. So it is catagorically incorrect to hold to one's opinion of perceived sound as an unassailable truth. It is THEIR truth but you and I might hear it much more differently than they did. Just take part in a speaker or interconnect cable double-blind study sometime. You will hear differences, sometimes, between various products. But can you really differentiate to the point whereby you say that "Number 1 is Nordost" and "Number 2 is Radio Shack"? Try it sometime. The results are going to amaze you and reveal new truths heretofor undiscovered. Therefor, you are the ultimate judge of the truth and you can only do that by comparing different equipment in your system. NEVER go by reputation. ONLY go by what pleases your ears. Music should just be equated with joy (not ego) whether you cry at an opera or bang your head with Kiss. I've done both and I am the better for it.

Gmkane, thanks very much for that info... Best answer yet to the question that drove me to start the thread. Thanks...

I have read many of the discussion boards here over the past year or so and I was especially interested in this particular discussion as well as the analog vs. digital discussion found in another emotionally-charged confluence of differing opinions. Below my preamble I have included a plagerized excerpt from a Soundstage review. I think it is very noticable that many people understand what they themselves have learned but have trouble conveying it to others with the same depth of understanding that they themselves enjoy. Whether they are right or wrong is irrelevant to them because they KNOW the gospel according to them. That being said I offer this thought for consideration: What sounds great to your ear might be mud to another's ear. It is the perception of the truth and not the truth that matters to us when listening. Do you hear some things for the first time when changing cables or do you just notice them for the first time because you have gone into a VERY active listening mode instead of a somewhat passive listening mode because you heard the source so many times before? I agree with Carl that digital is theoretically better at sound reproduction than vinyl, but keep in mind that CD technology is relatively new as music reproduction time lines go and it is really almost barbaric when compared to what will be heard from that technology within 10 years. Remember seeing the first Edison recordings that were made on the laquer tubes? Compare that to today's vinyl. Problem with vinyl is that, although it can still be optimized, it is a technology whose time has come and gone. It will be surpassed by the digital domain. I do disagree with Carl however in his observations about women, finding them overgeneralized and sophomoric (and yes I am a guy). There are differences between brain usage between women and men, to some degree, and women might be more attuned to certain areas of stimulation than men. However, I take exception with anyone who thinks that a man and woman can not be moved just as passionately by music or hear/appreciate the same dynamics. Just not true. Totally gender neutral. There are women who are just as scientifically curious as any man - ever hear of Madame Curie? I work with them every day and they are EE's and physicists. Depending on your system, you might not be able to tell the difference between those drums being played across the street for real or being played on a good recording through an optimized system. You know they are real because that kid is banging away, making msitakes, playing along to music he has playing, etc. You can tell from the acoustics right away. But if a really talented recording engineer went into that space, recorded that kid banging away with all the echo, attack, and decay - then you did an A/B listening test - I think you'd be hard pressed to tell the difference. The reason we know this is true is that it has been done before and more than not were fooled. But the music reproduction system would cost you upwards of $100k. As the digital technology advances, the breakthroughs in software and hardware will bring much of that front end cost down. The problem with digital vs. vinyl is that most people hear a pure "streaming" data set when listening to vinyl. It is infinite in its attack, transients, harmonics, etc. So vinyl picks up the harmonics and decay from transients better than digital - up till now. As you read through the information below, you will see why Carl is right in theory but the author teaches the lesson with great KNOWLEDGE and the ability to impart his knowledge to others. Here it is: Data-word length Some background. Here’s what a random 16-bit data word looks like for CD audio: 0011011000101110 There are 65,536 different values represented by the 16 digital bits (2 raised to the 16th power). Each of these values represents a voltage in the analog output signal. If the DAC IC outputs two volts maximum, then each different value for the 16 bits represents .0000305 of a volt (this isn’t a precise analysis, just a general conceptual overview). 0000000000000000 = zero volts 0000000000000001 = .0000305 volts 0000000000000010 = .0000610 volts 0000000000000011 = .0000915 volts 1111111111111111 = 2 volts If you increase the word length from 16 bits to 24 bits, the number of different voltages you can represent increases from 65,536 to 16,777,216 (2 raised to the 24th power). Each step in a 24-bit word would represent .00000006 volts, still using our 2-volt output model, compared to the .0000305 volts for each step in a 16-bit word (using the same 2-volt output example). You can see that the granularity in voltages representing the musical signal is incredibly fine when the data words are 24 bits long. Take an example where the audio signal wants to be .0000455 volts (still in our 2-volt example). With 16 bits available, software has to decide whether to make this voltage become .0000305 or .0000610 volts. There is no way with 16 bits to make a voltage that is .0000455 volts. But in the 24 bit world, you have an extra 256 different voltages available between .0000305 and .0000610 volts. One of them will be almost exactly .0000455 volts. Twenty-four bits is really higher in resolution than any consumer analog or digital audio products can achieve due to limitations in current electronic technology. Most digital products with claimed 24-bit performance lose probably three to four bits in the noise floor. But nevertheless, it is advantageous and comforting to have a digital standard that actually exceeds the capabilities of performance in consumer audio components. I’m not sure you would want to listen to music that requires all 24 bits to reproduce anyway; the loudest sounds would be as loud or louder than the loudest noise you ever heard in your life, well beyond the threshold of pain. The quietest sounds would require the total silence of an anechoic chamber to be able to hear them. What 24 bits brings to the table is headroom and footroom, which make digital audio more forgiving and easier to work with and offers an improvement in resolution even if limited to 20 or 21 bits of effective resolution. The circuitry in the D2D-1 creates a higher resolution digital audio bitstream by analyzing sequential groups of 16-bit data words and generating interpolated (best guess) 24-bit data words to replace the original 16-bit words. The process does have some margin for error, but it is vanishingly low. Keep in mind that in converting 16-bit audio to 24-bit audio does not increase the resolution of the reproduced audio. You can’t have more than 16 bits of resolution when you start with 16 bits of data, but the higher resolution digital bitstream can be more optimally transmitted and processed to make small improvements in sound quality.

It's not that I dislike Wadia, I like the company. They are superb in most respects, as many of you know.

Someone deleted the whole Resolution Audio thread? That's a shame...

Why does Carl dislike Wadia so much???

I see that some posts were deleted from this thread as well as the "What the heck is Res Audio" thread. Did someone cry to mommy?

For anyone interested, please see my 8/6 post under "what the heck is resoluion audio"....I'm tired of writing the same thing over and over again with regards to Carl.

You are a petty human, Deborah. I'll pray for you.

Deb; I didn't even mean for the above Garfish 8/5 post to be posted. And it is of course only a partially composed message in any event. I thought I hit "reset" and thus erased it. Sorry. Craig

Yep Garfish, it's all in good fun. I'm glad someone finally caught on. I find allot of the stuff on these threads "chow" for thought. And I'm glad my humor was not totally lost. Ciao, for now.

Hi Deborah1; Perhaps you're just humorously playing with words when you end your , but perhaps not. And It's not my intent to be demeaning in this observation: "chow" = food, but "Ciao" (also pronounced "chow") is an Italian? word usually used to express a pleasant Good bye. for goo

Carl, what are you talking about? My name is Deborah, and my husbands name is Robert. We are both professional musicans who reside in NY. My husband and I share many of the same viewpoints, and sometimes we even share this audiogon accout, but I assure you, these thoughts are my own. My husband has enjoyed all this very much however, and he especially enjoyed the post from Skohli on 8/3. It had him laughing for days. Chow!

And regarding "Deborah", I feel it is he who should apologize, for hiding behind his wife's name, because he's afraids we'll all know his real name. My observatiuons on women need no apology, because they are factual observations. I love them very much, but the two genders are different, and no one need apologize for that.

Jordan, your need to "call me" anything seems to highlight anger issues on your part. It looks like I will be e-mailing Jeff Kalt, and perhaps someone else as well.

After reading Carl's recent post in "What the heck is Resolution Audio" I reached the point (that I'm sure all of you have at one point or another) that I have to call a spade a spade so to speak. Carl is full of crap!! At least on the upsampling/oversampling topic he is. He may be even more than that! I noticed he took this topic over to the "What the heck is Resolution Audio" thread and started spouting about things (upsampling) he obviously does not understand. I tried to be gracious on this thread when his hero Jeff Kalt of Resolution audio confirmed to me by e-mail (posted above) that there is NO difference between upsampling and oversampling AND that mfg's were just using the new terminology to draw interest. However, I lost it a little on my recent post on "What the heck is Resolution Audio". Sorry guys (and girls) if you feel I'm polluting the thread with a little anger, but someone has to call him out on this one! Live the good life. Jordan

Ahem. Ok. Guys. Enough. Lets be adults here. Carl is entitled to his opinion, just as we all are. But really, guys, can't we all just get along?? Carl, be nice, too, please, there's lots of good knowledge on this thread, but you keep gettin the newbies all riled up. Thanks.

Carl, I think you missed the point about the apology thing. None of us doubt your views on audio, and although we all might not agree with each other all of the time, well, that only makes things more interesting. And yes, you are very rational AND knowledgeable, at least when it comes to this audio hobby. When it comes to women, well that is another story. And I believe it was your remarks about WOMEN that Onhwy61 was refering to when he said I deserved an apology; nothing to do with audio at all. But keep defending your view point(s), and if you read between the lines, you'll see that most of us are on the same page as you.

Hi Carl; I certainly hope you don't think (that I think) that your opinions are irrational on this subject-- we're all doing our best to understand it and its significance. You actually understand many of the details of this complex engineering subject, whereas I never will. I respect you, your views, and enjoy your posts. As to this subject; as a result of responses from Jeff Kalt (by Greysquirrel), Theta Digital, and Madrigal Audio, I've concluded that I was totally wrong about over-sampling vs upsampling-- these industry leaders apparently consider them the same thing, and I for one am glad to finally know this. My ego wasn't bruised at all when I found that my perceptions were wrong. As to differences in sound quality of digital components, I'll say again that Theta Digital is probably right when they say "implementation techniques vary". And that also explains why dCS gear may be so good (and so expensive) while others are building "up-sampling" components for a few hundred dollars. I'm looking forward to seeing Madrigal's position paper. Cheers. Craig.

There are those of you who seem to relish in your opinion that my views on this subject are irrational, and for that, you owe me an apology...not the other way around. I'm only defending my own viewpoints, here, afterall. And if you persist in harping about Jeff Kalt, I may just e-mail him myself, to see if the above comments from him are even real. I am a skeptic, afterall, at least as much so as you think you are...

I also emailed Madrigal Audio with the question of upsampling vs oversampling. I think it's fair to say that Madrigal also makes some pretty fine digital products, and I have their ML 37 transport and ML 360S DAC. Their response-- from Customer Relations: "We're actually about ready to post a position paper on this very subject on our (web) site. You'll see it there soon. To help our Mark Levinson customers understand more about what's going on inside their processors (already), we're about to release new software that will allow the customer to see the output sampling rate (versus the input rate, which is what they see in the display now) with the touch of a few buttons. Mind you, this is all the new software does; add a feature not a capability, as OUR DACs HAVE BEEN DOING THIS UP-SAMPLING (OVER-SAMPLING) FROM THE VERY BEGINNING. Stay tuned and thanks again for asking about the facts versus the hype." Todd Sutherland, Madrigal Audio. (emphasis mine re: capital letters). As to the differences in music quality/character among different CD players and DACs, I think the Theta Digital response summed it up best: "implementation techniques vary". Madrigal has a nice web site, and I recommend that anyone interested in this subject check out their position paper. I don't know exactly when it will be posted. This whole thread has been very informative-- well mostly. Thanks. Craig

Thanks Onhwy61, but no apolpgy necessary from Carl. His remarks were so outrageous that I just had to laugh. I guess I did get SOME retribution: it seems us "less curious" types are not as easily swayed by what in the end is MARKETING HYPE! (see my post on 7/31) And this from Carl's FAVORITE digital guy, Jeff Kalt @ Resolution Audio! BTW Carl, kudos to you for sticking to your guns: I've seen on another thread ("What is Resolution Audio") that you even DISAGREE with MR. KALT on this topic of upsampling! Seriously though, we must all remember one thing, and this just might come to aid Carl's position in this matter (is that ironic or what)....Just because we have no rational explaination for how or why something affects sound reproduction, that does not mean it has no real effect; especially if "skilled" listeners hear a difference. Our brains seem to be able to perceive HUGE differences in sound quality where none exist on the test bench or in the designers lab. So maybe upsampling falls into this catagory; it can't be justified from a technical point of view, but it still somehow improves our perception of the quality of reproduced sound. But I do think Jeff Kalt made a valid point in his e-mail to Greysquirrel: different is not always better, or more accurate. And thanks Greysquirrel: this has been one of the most heated thread topics I can remember!

Thanks Megasam, the HFNRR article was most interesting. Thanks Greysquirrel for going to a source with cred. I agree with Carl's first 8/2 posting -- yes, you are not the real expert here. BTW, you really do owe Deborah1 an apology. Your 8/1 comments are way out of line, IMHO.

Check out the MSB site's description of their new Platinum DAC where they take a stab at describing the differences. BTW this is an excellent unit. I replaced by Theta Pro Gen Va upraded to 96k with the MSB Platinum unit. I directly compared the Perpetual Technologies upsampler with both DACs and thought the result was inferior. I actually had the dCs units in my system on a borrowed basis earlier this year. In my opinion (but from my memory) while they gave better sound the Platinum covers more than half the distance from the Theta to the dCs. The Platinum's balanced outputs are able to drive my power amp directly from the DAC without an intermediate analog buffer stage. I think good comparison to heat the effects of the digital processing, if you have an excellent analog rig, is to compare the RCA Reiner recordings of Bartok's Concerto for Orchestra and Music for Strings Percussion and Celesta on the Classics Records vinyl to the most recent remaster on CD. These recordings are some of the most realistic recordings of a symphony orchestra ever made. The difference with upsampling jumps out. (The vinyl is still better but not so much that really bothers me)

Again I advise reading August HFNRR, which describes the two techniques, although they can acheive the same end result, the "process" is different......read and find out the differences, they claim they can hear the difference

I guess Jeff Kalt is a better man than me. That's why I bought his CD player over a year ago. I guess since there's no difference in upsampling and oversampling, then there'd be no difference between my CD50, and the new CD55. I'm ok with that, too. Why aren't you, you little squirrely thing, you?

Hi Greysquirrel-- excellent post, and thanks. Finally an answer to the oversampling versus upsampling question from someone who really does know. And I now admit that my original perception, that the two were different, was wrong. You may be interested to know that I emailed Theta Digital with essentially the same question. I got a reply from their Customer Services Rep. (not an engineer or designer); the Rep. asked their digital designers, and they flatly told him that "over-sampling and upsampling are the same thing", but implementation techniques vary. Cheers. Craig.

Carl, it seems that Resolution Audio wasn't frustrated by my question. Why must you?

The following is the actual e-mail (in entirety) sent to me (this morning) by Resolution Audio in response to my question concerning upsampling / oversampling (the question was almost verbatim to my original question above). Indeed, there is no technical difference between upsampling and oversampling. The only difference I can discern is in the marketing. Indeed, digital filters can be very aggressive above the audio band without the adverse effects that analog brick-wall filters have. This is possible because of FIR (finite-impulse response) filters, which have constant group delay (zero phase effect vs. frequency). There is no physical realization of an FIR filter in analog. Using FIR digital filters allows the analog filter to be relaxed significantly, because the first "images" are located at much higher frequencies. In our cd55, we use a passive third order filter which is down only 0.2 dB at 20 kHz, yet the rejection of the images at 700 kHz is about 60 dB. And indeed, the digital filters do not create information that may have existed before the mic feed was converted to digital. Some external "upsamplers" may by their nature apply some other filter/eq, but this is independent of the a/d - d/a process. You are also correct regarding the delta-sigma dacs. These dacs are rated for maximum input rate, currently as high as 192 kHz. These converters all run at the output at much higher rates -- typically 12 MHz or thereabouts. The better ones from Analog Devices use extra filter stages when the input rate is lower. Essentially, the dacs run, say, 256x at 44.1 or 48 kHz, 128x at 88.2 or 96, and 64x at 176.4 or 192. This puts the noise modulator heart of the converter at the same frequency regardless of input. The best multi-bits, including the PCM1704, run upwards of 800 kHz, which allows 16x at 44.1 (and 8x at 96, and 4x at 192 input rates). In sum, your perception of "market jargon to draw interest" is dead-on. In addition to preying on the consumer base which generally does not have engineering degrees (and some manufacturers as well), these products offer the opportunity to sneak in digital eqs which will absolutely sound different. Better? That's a different story. Finally, we have just started talking to a dealer in Indiana. If all goes well, I'll pass along the info in a couple of days. Regards, Jeff Kalt Resolution Audio resaudio@ix.netcom.com

Carl, that was very helpful.Thank you for taking the time to offer such a clear summary. I'll get back to you all after I hear the Bel Canto DAC1 next week.

I thought I'd done the laymen thing already, and as you'll probably see, I may still fail at that yet...........As said above by MSB (posted by perhaps an F-14 pilot?), interpolation occurs when voltage amplitude values are APPROXIMATED during this up-conversion from CD resolution data, to much HIGHER resolution data. It's sort of like a line doubler for video projectors...sort of, but not exactly..................I think of it in this simple way: the conversion of the audio data, in the digital domain, to a higher bit and sampling rate (upsampling), allow the high performance DAC to do its conversion on this LARGE amount of data, thus making full use of the DAC's superior resolution. IT'S NOT A MATTER OF CREATING NEW DETAILS IN THE RECORDING that were never there to begin with, it's a matter of getting the most out of what was always there...just like everything else in this hobby.......................It's also not merely "digital" we're talking about, but rather how the digital data gets turned into the analog voltages/waveforms...before it goes to your amp, or preamp. THAT'S ALWAYS THE MOST IMPORTANT THING IN DIGITAL AUDIO. Otherwise, you're making assumptions like my smug, MIT graduated, aeronautical engineer uncle. He's said the cliche right to my face, "but digital is digital; how could one CD player possibly sound different from another one?" You know, the old/stupid "bits is bits" argument, only he didn't even bother to think of it on that level............No DAC is perfect, but it is the critical "roadblock-weaklink" in the digital playback chain. Therefore, if you can make use of a "superDAC" on "mere" CD audio, it's much better than using DACs that operate only on the level of "CD quality" data................Anyway, audio is always about maximizing your UPSTREAM performance, in order to make full use of what you have DOWNSTREAM. UPSAMPLING "guesses" at many extra millions of possible "loudness" levels (and frequency "pulses" in time) in the digital data, BEFORE IT EVER GETS TO THE DAC (that needs all the "help" it can get)..............As perhaps most who'll read this know, SACD uses a different digital process, that samples at nearly 3 million times a second, and only uses one "loudness" bit, to tell if the waveform is rising or falling. It depends on the sheer density of those 2.8 million pulses every second, to describe how quiet or how loud the music is...............It's all much more complicated than this, but oh well, I'm not the real expert here...either from a designer's viewpoint, or from a journalist's viewpoint.

I emailed MSB yesterday regarding the Link DAC III's ability to INTERPOLATE AND UPSAMPLE. The response was as follows:

Thomas, We do have this available, we call it our upsampling upgrade. It does smart interpolation and upsamples the signal to 24/96kHz as well as 24/132kHz.

This upgrade is $199.00 and can be installed by the customer at any time.

Thank you for your interest, Scott Rust MSB TECHNOLOGY This information lead me to order a Link DAC III with the upsampling and interpolation chip. When I asked the Scott why does MSB not state anything about Interpolation on their website, he said "Nobody Knows what Interpolation is". Anyway. I have Pioneer DV-414 as the transport and the Link DAC III will complement it. I just thought I would interject my ignorance or 2 cents which ever is worth more!

WOW! Lets get back to the topic(s). I too am very curious about the latest developments in DAC technologies. Carl, maybe it would help us layman if you could explain upsampling using an analogy (like when math teachers use a pie to help students visualize the concept of division)... it might seem silly but it would help get us out of the abstract world and into the physical world where things are easier to understand. You would be doing us all a great service if you could find a way to clarify this once and for all. Anyway, I do have a friend coming over this weekend with the Bel Canto DAC1, so I might have some more to say about that product early next week.

All I did was try to stick to the thread topic, and yet it seems someone using a woman's name doesn't like that most audiophiles simply like "gadgets" and how things work, besides their love for music. I won't apologize for this, and I am even proud of it! It's in the nature of most men to be curious about the workings of the physical world (and it doesn't seem to be that way for most women). It helps them appreciate it better...whereas those who aren't curious about these "tidbits" very often seem to have little or no appreciation for them. (I.e., on interstate highways, women driving their SUV's...aren't thinking about how heavy an 18 wheeler is, so they very often drive in their large blindspots, only thinking about staying around the speed limit...rather than foreseeing the possibility that the trucker might suddenly need to change lanes. Don't tell me any of you haven't seen this a billion times, as well!) It's all a question of personal prioroties and observatonal logic/natural curiousity). And, I feel that my views on audio in general are representative of perhaps 80% of "audiophiles". Also, we don't listen to music because we don't love it...

OK, guys, read the thread topic, and please stick to it. ALso, BE NICE! Otherwise, I'm gonna put all of you in "time out"

It's interesting, the emotional truth at the core of music has nothing to do with the quality of the sound. Maybe that's why alot of musicians don't have audiophile quality systems. The music really is only in your head. Deaf people have composed symphonies and I bet they "hear" it better than most people.

It's interesting, the emotional truth at the core of music has nothing to do with the quality of the sound. Maybe that's why alot of musicians don't have audiophile quality systems. The music really is only in your head. Deaf people have composed symphonies and I bet they "hear" it better than most people.

I know this thread has gotton way off base, and is now a bit out of control. I suppose I'm as much to blame for this as anyone, so I apoligize, especially if I offended any readers. I have no doubt that most of us are passionate listeners and lovers of fine recorded (and live) music. If you read my previous post carefully, I specifically state that this new technology (upsampling) might in fact be better. And I also state that I plan to find out for myself one day. I'm not down on upsampling or any new development in the audio world. I just think we (myself included) can get carried away with the gear and audiophile thing. Home music reproduction has gotton so good, that most of these (or any) new developments are MINUTIA. True, many years of minutia will add up to a worthwhile improvement in sound. And maybe upsampling is the culmination of many years of 16/44 research. But has anyone checked out SACD? I had a player and 30 or so titles for about 2 months. Was the wait worth the hype? NOT AT ALL! Yes, it is in some ways a step forward, but not a HUGE step closer to musical (read emotional)truth, at least not IMHO. If we call ourselves CAREFUL listeners, I hope we mean carefully listening to the MUSIC. Not the wires, speakers, upsamplers, etc. In the end, we should just forget all this and enjoy ourselves, which I'm sure most of us do, most of the time. Anyway, my crack about forgetting how to have fun (again, read my previous post) was really NOT aimed at the listeners, it was meant to be aimed at the name calling, frustrated replies, and snide remarks found in many of these threads; and it's usually the same handful of culprits who seem to do it. Anyway, someone should have the right to ask a question without having to worry about getting beat up for asking it. And if it is explained to them and they still do not get it, either patiently try again, or let it go. Why respond with insults? Anyway, I'm sure I'll get bashed for this thread, and in some way my point will be proven. I hope however, that I am proven wrong. Nuf' said.

Hey, not bad Carl. My apt is to small for live music,as is most everybodys'(music room) Can't play a lick of anything.--All I got is my love for music playback; and my system. In reading,year after year people like Les Paul,Allan Parsons,all have one thing in common;Budget equiptment. Playing,over the years, for musicians, (listening in Allan Parsons case) has done something,It may be because it is their JOB.(Not an informed opinin) They may love performing,but it ends there. They know,as do we,nothing compares to live,and have little interest in our hobby,hey that's fine with me.I do have Purcell. working on Delius.It ain't just upsampling,It is HOW it is done.(like playing music).

I certainly know how to enjoy listening to recorded music, and it seems to me that you are the one that doesn't know how to do that. Perhaps it's true with all musicians, but it seems that they're never happy listening, only playing. That's fine with me, and also a good thing; otherwise they wouldn't be playing what gets recorded, or playing live. But don't presume to tell me that I'm not having fun, just because I listen to recorded music. And regarding marketing hype, it's very easy for anyone in the world to just sit back, and spout that things that others have experienced THAT THEY THEMSELVES HAVE NOT, and are enthusiastic about, is all just "hype". I too think that there's a lot of "hype" in the world, and I really don't care if you think upsampling is "hype" or not...Go back to playing with your world class chums, and let us enjoy music the way we can, and stop begrudging it.

I really don't have much to add, except to say that I too am curious about the sonic benifits (if any) of upsampling technology. I will make several observatons, however: Observation #1-A few years ago, many high end companies were crying (in writing to the audio press) that the sales of CD players were droping off because the press was spending too much time talking about the "new" audio formats "soon" to be released, and that the press was discouraging people from investing in newer CD playback units. But now, thanks to upsampling, 24/96, and all that jazz, we're all talking about CD players again. Just a coincidence? Maybe upsampling is "better", but maybe it's just marketing hype. I plan to find out for myself one day. Anyway, on to observaton #2- some people on this site need to lighten up! Remember, this is a HOBBY; it is supposed to be FUN! All the frustration and name calling I see in this discussion group can be a real drag. And the truth of the matter is this. No matter what you buy, no matter how much you spend, no matter how much new technology improves sound quality, no matter how superior your technical understanding is, and no matter how much more "analog" someting sounds---NOTHING WILL EVER SOUND LIKE REAL MUSIC! (the truth hurts, don't it?)----Right now the kid across the street from me is playing (smashing) the drums. I know for damm sure that racket I'm hearing it is not a home stereo. How can that be? Without soundstage depth, height, imaging, tonal balance, acoustical treatments, etc...I can easily tell the difference between live music and recorded music. BTY, I'm a professional jazz musician. I play 3-6 nights a week, 52 weeks a year, all around the world, with some of the greatest musicians alive. I have a stereo system with a retail value of over $15,000. And it never once fooled me. Maybe we need to upsamle our personalities: some of us have lost the ability to have fun:) Keep it real, and in perspective.

Thanks Onhwy61. I'm not ashamed to admit that I'm a little confused about this subject. The two processes appear VERY similar to me and yet there is quite a stir about upsampling DACs.

dCS, the British company that made the first upsampler product, readily admits that there is no known reason why upsampling should sound any better than oversampling. The processes are fundamentally the same. Since many well-trained listeners report that upsampled data sounds more natural and realistic than oversampled equivalents, then I think it is reasonable for listeners and manufacturers to be somewhat confused.

Perhaps I need to ask an even more elementary question to clear my confusion: with an upsampled datastream, what "information" is populated into the additional 16,711,680 word states (16 bit to 24 bit) and what information is packed in between the sampling points (44.1 to 96,192,706,768 kHz)? MSB has returned my e-mail and confirmed that the improvements brought about by upsampling (at least as they implement it) are primarily due to the ability to filter more aggressively outside the audio band, as well as the ability to utilize the greater linearity of the 24 bit DACS they use. Haven't heard back yet from Resolution Audio or Wadia yet, but will post their response when they do.

I'm trying to tell you, I don't know how else to put it. Oversampling still sends the same data to the DAC. Upsampling sends the DAC data that has been sample rate converted to a much higher resolution format, while still in the digital domain. Oversampling means we are still talking about a DAC that converts 16 bit/44.1 PCM code, to analog. An upsampled data stream is sent to a DAC that (depending on what bit rate/sample rate that data is) is converted to analog with a DAC that could be 24/96, 24/192, 24/706, or 24/768........I thought all of this was common knowledge, and can't understand why you are confused. Certainly any manufacturer will be frustrated by these questions, it seems to me.

Megasam, just went out to the local Borders and read the article in "HiFi News and Record Review". Thanks for the notice. Not sure what they were trying to suggest? They only compared the sound of two different units. I would have liked to hear about the differences wrought by sending the Wadia an upsampled data stream via Purcel or Delius (can't keep straight which is the "upsampler"). After reading that article, I'm still left with the same feeling: oversampling and upsampling are VERY similar as far as the processes go. Implementation (how much over/up sampling and amount of dither added) and choice of filter algorithm is likely to be most significant to overall sound. How do you "resample" a digital datastream? You oversample and interpolate the points between original sampling points. You may increase word length also, but this does nothing unless you add dither. I'm not an expert on this, but I do think I'm not far off. I've e-mailed several mfg's with specific questions regarding upsampling/oversampling. Haven't heard back yet, but if it turns out I'm way off base here, I'll report it here and eat my helping of crow. Just want to understand. Greysquirrel

It's a shame that Wadia might feel negatively towards upsampling, because their slow roll off filter in their DAC would greatly benefit if it were rolled off way above the audible frequency range, instead of WITHIN the audible range. I had assumed they were moving towards upsampling. Perhaps they'll eventually catch up to the rest...

Anyone interested read latest Hi-Fi News & Record Review (August) they have good article on this subject. Wadia apparantly is saying upsampling is no better than their oversampling techniques. Magazine compares latest Wadia 860 against DCS Delius 24/192 upsample unit. Gives good overview of both methods of data processing, too complex to explain here, please read article. To summarize they say Wadia has perfected the CD sound to its highest level, but it still has underlying CD sound characteristics. DCS Delius using upsample somehow takes same data from CD and transforms sound in positive ways to sound more real than traditional oversample. There is no scientific explanation at this time, just subjective opinions of reviewers, regards Sam

With upsampling, the digital audio is actually re-sampled, and has nothing to do with the filters in the DAC. The data is sample rate converted to a HIGHER resolution digital format (while in the digital domain), before it even gets to the DAC. The first units of this type used two separate chassis. One was a "sample rate converter", or "digital-to-digital" converter. The data was then sent to a DAC in another chassis. Lately, all-in-one-box units of all types are popping up.

Craig, yes dither (white noise) is added to increase resolution. Not sure exactly how that works, but I believe it elevates the recorded data up from the near the least significant bit, reducing quantization errors. Interpolation is basically what is done whenever you increase the sampling rate by some multiple. I don't think that early "oversampling" designs were adding dither before decoding? But if this is the only difference, then my last statement above is probably right: mfg's found better ways to implement oversampling techniques and are marketing them as the "upsampling" process? Either way, it sounds like most listeners have found well done upsampling/oversampling to be a significant improvement.