Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

41 thoughts on “Taking It On Faith

  • Dick James

    I still think you are leaving out of your discussions the affects of BER (bit error ratio) and whether the equipment is buffering the data stream to hide all the delays caused by error corrections, re-broadcast of packets for Ethernet, USB, and SATA, etc. It all creates a lower overall BER. More expensive equipment has better buffering, lower BER for their digital interfaces, etc. The cheap stuff, especially older equipment, has no to little buffering at all and the BER is more noticeable. The goal of the gold-plated CDs, SHM discs, better cables, and other stuff is to reduce BER. BER is rarely 0. The Red Book specification for CD manufacturers, I believe, specifies a maximum BER of 10^-5 (1 errored bit out of 100,000 bits), but you probably know the specified BER better than me since I’ve never found a copy of Red Book that didn’t cost me money.

    I don’t buy any of the expensive extra stuff because my sound system would probably not provide any noticeable improvement.

    • Dick, I take your point…there are certainly variants in data accuracy etc. But when any system passes identical data streams to identical playback systems…the sonic result is identical.

  • Don Hills

    Regarding the description from FIM of the disc mastering process you quoted, I think Paul McGowan summed it up very well at the beginning of his series of posts on why “identical” CDs might sound different: “Giving facts to the reader that misdirect, yet are accurate, is a key element in the writing of a mystery novel.”

    • The FIM techno-speak and the fact that Elusive Disc would reprint their misleading dribble is problematic. I took Paul’s initial comments to mean, “don’t listen to engineers…especially the ‘bits are bits’ crowd because they twist the information”. I would push back and say that Paul and the “flat earth” crowd are the ones pushing the false agenda.

  • There was a time when Paul McGown was a bright star in High End Audio. His PS Audio company was dedicated to designing and building high end sounding products and bringing them to market at beer budget prices. I owned his PS iii phono preamp and had it running in my system for 25+ years. I did some comparisons with a number of expensive units over the years and never heard a compelling reason to spend big money on an upgrade.
    Too bad over the year Paul has slid to the dark side, selling overpriced components,
    and making snake oil advertising claims for his products.
    Why would anyone want a DAC that converts everything to DSD with no choice given the user. 🙁

  • Donald Scarinci

    I am not sure that you and Paul McGown are communicating. You are both right. CD’s are 1’s and 0’s and there is nothing else there. However, the equipment that translates those 1’s and 0’s to audible sound is all very different depending on what you are using.

    Not even you can argue that the new PS Audio DAC makes the music sound significantly “better” then, for example, the DAC in an Oppo or a Meridian Explorer. When those 1’s and 0’s are “translated” into sound, the playback equipment and the quality of the audio system determine how you hear them.

    Paul McGowen is not the only person who “hears more” on a CD when it is played through one of his DACs. I hear it too. In reality neither Paul, me or anyone else who hears it isn’t hearing anything that isn’t already on the CD in the form of 1’s and 0’s. The digital information has always been there. It was just not recognizable to our ear because lesser quality DACs and DAC’s using old technology or the DAC chips that every other manufacture uses in their equipment couldn’t translate it.

    You cannot paint Paul McGowen with the “snake oil salesman” brush. The innovations he has made with power regeneration, CD transports and DAC technology have been game changers. Compare a CD played in an Oppo (and I love the Oppo 105, I’m not bashing it), with that same CD played in PS Audio’s new DAC and tell me you are not hearing more detail! You are. The reason doesn’t have anything to do with the CD. It has everything to do with the translation to audible sound made by the DAC that is used.

    • The signal path from a CD to the final output depends on a large number of factors. Unless, I’m misreading Paul’s posts, I believe he’s trying explain why playback from a hard drive and CD of the same program can sound different. The plain and simple fact is they can’t given all else being equal. DACs and clocking, amplifiers etc…all have important roles to play. But the bits stay the same.

      We do differ in his insistence on DSD conversion. I would never ever submit my pristine streams to a conversion to DSD. I won’t ever record using a system as flawed as DSD and I find it very troubling that so many advocates of DSD and SACD don’t do the research necessary to understand how unimportant it is.

  • I’ve owned a few PSA products in the past (still have some AC cords), but I haven’t been on the PSA website very much over the past few years.

    In my experience, his products sound ok, but are nowhere close to being as good as the fanboys over there think they are – in their eyes, everything PSA makes is a “giant killer” and most of the people over there take everything Paul says as gospel. It got a bit tiresome which is why I don’t hang out there anymore (also The Bridge sucks, but that’s a whole ‘nother story).

    As for Paul, he is a very good marketer and snake oil peddler and it looks like not much has changed. As I read these posts, I was trying to figure out what he was trying to sell. At first, I thought he must be trying to get rid of all of those Perfect Wave Transports he must have sitting on the shelves. But it turns out it’s their first album and it looks like he’s trying to get people to buy multiple copies so they can see if they hear differences.

    So in addition to the forum having threads dedicated to “which firmware version sounds best on the Directstream DAC”, now people will also be arguing over which version of the album sounds best and, of course, someone with a CD version will have to get the DSD version too after Paul posts how good it sounds on firmware ver 2.4.

    He’s good. He’s very good.

    • Looks like my first thought about Paul trying to get rid of Perfect Wave Transports might have been correct — Moon Audio is giving away a PWT with the purchase of a DirectStream DAC.

      Will be interesting to see if the other on-line vendors start offering the same deal.

  • Chas Boyce

    Are these people saying the medium for the digital data has less errors, thus less error correction circuitry involvement? If not, why do they not understand the binary system? I can understand 0 and 1, but a better 0 and 1? Either it is there or not – correct?
    I do have CD’s with errors beyond what my hardware could play without serious errors. Maybe these 0 and 1 charmers are speaking of their discs without such errors.

  • Hello Mark, I think I mentioned once before on one of your post a very long time ago, when you raised a similar point to the ridiculous claims in today’s paragraph from Elusive Disc, that this is a very old idea that I first remember reading about in hi-fi news in the 1980s. The main idea being that if the disc reading mechanism has to work really hard to correctly read every bit of data, then its power supply fluctuations might logically feed back into the power supply of the analog circuitry downstream of the DAC. Possibly either through the shared power supply unit, or even back through the mains plans of the two PSUs, or the other alternative being that if the digital circuitry power supply unit is nonlinear then it may be emitting radio frequencies and these could be pulsing or whatever and somehow inject themselves into the analog circuitry downstream of the DAC.

    That’s the usual line of thinking behind claims that digital disc servos need to be given the easiest task possible. I’m certainly not defending it, so feel free to ridicule the motion, but at least somebody was trying to be logical even if it is very highly implausible or requires essentially heroically misconceived circuit design in order to happen in practice at a level that would have an audible impact.

    • Think Morse Code…the server can move as much as it wants, all I want out the other end is the stream.

  • How do we get past the continued fiction spewed by high-end makers of hardware, cables, and even software?

    That’s a good question. At one time I thought consumer protection legislation could reduce these kinds of fraud but the complaints have to be followed up by real people who are able to exert real consequences for non-compliance. In Canada, where I live, the government is doing away with consumer protection. I’m sure it’s similar in the USA.

  • Boomer Bill Calkins

    Mr. McGowan does not understand how amplifiers work, tube or transistor. It is really shocking. Many of his posts are simply incorrect when he explains how circuitry works. I have corresponded with him often on these matters. It is not surprising that he needed to consult with Bascomb King in designing the new high power amplifier. I am glad they got it right. I have chosen to unsubscribe form his blog. Too bad. He does have some good ideas and understands the value of the recording engineer’s skill.

  • Dave Griffin

    This is the the third time I’ve posted this response to this recurring CD bits are bits argument. You have to differentiate between file-based systems and those that rely on data-streaming.

    File-based systems will always be true “bits are bits” systems because the location of each bit is known. Copying data from a file based system is quite literally drag and drop (using a GUI-based front end, or whatever the copy command is in a terminal/DOS based window). Hard disk, DVD, Blu-Ray, internet (packet-based) systems will always be able to re-request any bad data; if the data is still not available after re-requesting then the error will be reported as data unobtainable. CD’s don’t work like that, they’re a bit-stream and data is effectively “thrown” at the DAC If there are errors then the DAC has to do a best guess at what the data was. In other words the error correction is effectively an interpolation on previous data and will not necessarily be a representation of the actual missing data on the disk. Anything that can corrupt that data-stream will ultimately affect the “sound” of the system because the DAC will have to “guess” what the data should have been.

    Bits are NOT bits when it comes to CD reproduction, ripping a CD accurately is almost an art form and needs to be done with software that does multiple passes to ensure consistency and even then compares those passes to checksums from previous rips using an internet database to verify that the rip is a “true rip”.

    • Thanks Dave…so how am I supposed to validate a stream as being identical to a file on a particular storage media? I can understand that real time transfer and the associated error correction. MY sense is that the tolerances of modern discs and players are tight enough to make this a moot point with high-end systems. No?

      • Dave Griffin

        The whole concept of this discussion is that CD falls into the “bits are bits” argument; you’re equating CD with DVD, Blu-Ray and any other file-based media; but CD, as a storage medium, is unique in that its data output is a bitstream. I can see your point about modern hardware, but the fact of the matter is that with CD the data reproduced by the DAC is NOT necessarily exactly what’s stored on the CD, you can’t make the “bits are bits” argument with CD, and the data retrieval COULD be influenced by, say, the quality of reflection/refraction in the media.

        For media which is file-based, bits are bits and no surface treatment will make any difference to the sound (although it could make life easier for the hardware, ie the disk is easier to read because it’s clean) so you argument in this case is valid.

        • Dave Griffin

          And btw there is no such thing as a file on CD, it’s a bitstream.

          • It is a bitstream…just like any other bitstream but that doesn’t really change anything.

        • Dave, I don’t think I’m with you on this. CD, DVDs and BDs all provide continuous streams of digital data. Are you saying that CD is the only one that delivers a bitstream. Having authored hundreds of DVD and dozens of BD discs, I believe they output a digital bitstream as well. In fact, the player let you decide whether to pass out bistream or not. I’ll have to research your claim because I find it hard to believe that the playback DAC is not entirely dependent on the output of digital data from a CD. If I play a CD in real time and capture it to a file and then rip the CD to a file and compare then (which I’ve done) the results are exact the same.

          The idea that a surface treatment will work on a CD and not on a DVD or BD disc is questionable. I’ll ask around.

          • Dave Griffin

            Goggle’s your friend on this.

          • I’ll certainly take a look…

          • Dave Griffin

            A CD is NOT a file based system, blu-ray, DVD is.

          • But it doesn’t matter if the result is a stream of bits, right?

          • Dave Griffin

            No. A file-based system uses two-way communication, a bad bit can be re-requested. A bitstream is one way only, the data has to be corrected at the receiving end. That is the fundamental difference. There are ways and means to try to get around this but ultimately a bitstream is one way only.

          • Dave, there is nothing preventing CD players from re-requesting data. Almost all of the old portable CD players did this, it was called skip protection.

            Also I don’t know of any generally accepted definition of file system that requires automatic re-requesting of data when there is a read error. If you do know of such an accepted definition, can you provide the definition and its source?

        • Dave,
          CD, DVD and Blu-Ray discs all store serial streams of bit data, and as such they are all bit stream. In 1988 Philips introduced the marketing term “Bitstream conversion” to describe 256x oversampling 1-bit DAC processing. Philips “Bitstream conversion” is processing of the data being read from a CD not how the data is stored on or read from the CD.
          The streams of bits on a CD are organized as 588 bit channel-data frames containing 24 bytes (192 bits) of data and 396 bits of control and error correction. These channel-data frames are then organized as timecode frames composed of 98 channel-data frames. Each timecode frame contains 1/75 sec of audio data. Tracks are composed of a minimum of 300 timecode frames. A TOC (Table of Contents) identifies the tracks and the location of each track. This is a file system regardless of whether or not the Red Book specification uses that term.
          Here is the beginning of the Wikipedia article on file systems. “In computing, a file system (or filesystem) is used to control how data is stored and retrieved. Without a file system, information placed in a storage area would be one large body of data with no way to tell where one piece of information stops and the next begins. By separating the data into individual pieces, and giving each piece a name, the information is easily separated and identified. Taking its name from the way paper-based information systems are named, each group of data is called a “file”. The structure and logic rules used to manage the groups of information and their names is called a “file system”.”

          • Thanks Mark…I can’t keep up with the nitty gritty of this but I believe I’m with you on the essentials.

  • Frank L.

    I have many CD’s and I mean many. Regular, fancy (chesky etc.) and some of the fancy XRCD. I recently compared some of the XRCD to their regular counterpart and guess what? Their spek was 100% I mean 100% identical. I tried everything to make the XRCD look differently, but to no avail. Same ol’, same ol’. All this voodoo sh…t is nothing but sales stuff. Sorry for the many XRCD customers that paid prime $ for their merchandise.

    • I’ve done the same thing…with the same result.

  • Errors in the bitstream are not an issue even real time from a CD.

    One experiment I did was using a really cheap DVD player to play back a CD-RW. One duplicated at 48x. Have also run regular CD’s from my earliest purchases. Sent the digital out from the DVD to a lowly Maudio Audiophile 24/96 sound card. Recorded the digital stream. Compared to the ripped files held on a hard drive with ripping done by Exact Audio Copy. Hours of such. Not one single error in the bits. Not one. This is real time reading by a cheap DVD player and no errors. None, nada, get it, zero errors. I am sure it is possible, it generally is not happening, and certainly nowhere to the point effects would be audible with any reasonable equipment.

    I took a CD-R and scuffed it up a little. No errors. Scuffed it up a bit more. No errors. Eventually, well past I would have thought playback possible, you did get errors and finally drops outs from it not reading.

    Lord if I know how to kill this bogus myth.

    • I was thinking about this today prior to reading your comment. If I record the S/P DIF output of my Oppo BD machine into my DAW and then compare that to a rip of the same disc and then to a file downloaded from the web, I’m sure they will be identical. I’ll have to try this…but I’m very confident that current technology will deliver the bits without uncorrectable errors.

  • Great post Mark and thank you for the shout out! I am delighted you post every day and I believe it is a benefit to the community.

    I sense we are on the same page here that the bits, despite the addition of magic goos and facial treatments at the CD spa, remain identical. I could not be more in agreement. My point in all this was exactly that. So where, one might ask, is the difference we hear when we treat things if the bits do not change? And the answer I keep coming back to is a simple one, in the read mechanisms of the machines doing the final data transfers themselves.

    Imagine just for a moment you have a CD or DVD disc that is difficult for the laser mechanism to read in one hand, and a specially treated perfect DVD in the other. When you play the one with problems, the laser mechanism and its error correction algorithms will work harder than when they read the pristine disc. We agree that the bits both examples spit out are the same, but where I believe the differences are lies in the increased levels of jitter added by a harder working power supply at the very moment where the clock is added to the data. That’s at least my best guess, though I admit it is only a guess.

    We know, for example, that reading and transferring and copying that same data from media to media, even if it is difficult to read as in the above example, makes no difference whatsoever. It can repeated over and over without affect. But the moment we read that data into the DAC and the clock is now added – things change and the game is fundamentally different.

    Anyway, just my two cents worth. Thanks again for posting every day! Keep up the great work.

    Paul McGowan

    • Hey, Paul…thanks for coming by my daily post site. As I said, you’ve been an inspiration for me in this whole writing thing. I think we’re on the same page basically. There are going to be things that result in sonic changes but I’m not convinced that Hard Drives, or OS versions, or the storage format play any role. Cheer.

  • I follow yours and Paul web post with great interest. It seems to me that a simple way to settle the merits of each others products would be to would be to take your recordings to his “shop” or have him bring his best products to your studio and have a listening session with you two and maybe your staffs. He could show you what improvements he is hearing using the Direct Wave and you could do the same using “PCM only” recordings. I think both of your readers would love to see this happen!
    I would be willing to send along some adult beverages of your choice to add to the enjoyment of the event!

    • I’m headed to Colorado in the next couple of weeks. He’s always had an open door for me and perhaps I can make it happen this time.

  • Phil Olenick

    One brief comment – of course CDs contain files – one per selection (a more neutral term than “song”).

    While the files have the extension .CDA (for “CD Audio”) they are simple PCM .WAV files.

    The term “Bitstream” is usually used to distinguish an output deliberately left in the form of a compressed codec (like Dolby or DTS) – for downstream decoding by an AVR – from already-decoded PCM.

    Thus, since what CDs put out are PCM, to say that CDs are not files but bitstreams is to turn the meanings of these terms upside down.

    • Thanks Phil…but can’t the “downstream” decoding be more than just DTS or DOlby? I think it’s possible to output PCM as a bitstream. I’m in Vail skiing right now…but will do some additional research when I return to LA>

      • Phil Olenick


        Any non-analog output will *always* be a stream of bits, even if it’s pure PCM.

        What I’m referring to is the way the term “bitstream” is used by home theater equipment: to distinguish a proprietary encoded (and usually data-compressed) stream like the many variants of Dolby and DTS – from a stream that’s pure PCM.

        I suppose that the term bitstream could even be used in this sense to refer to the HDCD format that uses the least-significant bit for dynamic range expansion to mimic 20 bit PCM.

        My point was that to denigrate CDs as not being file-based (wrong) because their output is a “bitstream” ignores both the fact that CDs are file-based and that the output is the kind of pure PCM that the normal usage of the term “bitstream” says it’s *not.*

  • I think it’s highly inappropriate to use the term snake oil and Paul Mcgowan in the same sentence. I’ve used his a number of his products over the years and they all performed well and for more than fair prices. Sure new versions of the same product sounded better than the old versions, but that is progress. And the fact that they have upgrade kits for the DAC is a great way to keep current.

    On to the DS. I had a PWD 1 and 2 which were excellent products for their era. The low jitter native X mode of the version 2 was quite an audible improvement – and I even using Native rather than up sampling was a great rethinking and sound improvement at the time (though there was a choice to oversample- it didn’t sound as good)

    The DS is in a whole other league and redefines what music reproduction can be (and at an attainable price point)

    I’m listening though TADc r 1’s which are extremely resolving point sources, and happen to hear live music from up close frequently (in homes and small venues). I even had a performer over who started singing along to a CSNY track and it was uncanny how similar live and recording were.

    The DS has such a simple output section and converts to analog so easily. It makes even some poorly recorded CD’s sound like fully fleshed out performances and good CD’s sound astonishing. High res even better and good DSD is even more magical. I also read about now being able to records multtrack in DSD.

    The DS simply must be heard to be evaluated.

    Paul has no trouble sett

    • I agree that Paul and PS Audio build very good products. The value proposition is another question…I don’t believe a $4000 CD player is money well spent. I also don’t believe that I said PS Audio is selling snake oil. The mandating of DSD as a “processor” in the DS is a mistake in my opinion. There is no redefining music by compromising it through conversion to DSD. The PCM original files are much better and as the producer intends. DSD is a huge mistake and compromises the quality of the end result.


Leave a Reply

Your email address will not be published. Required fields are marked *