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30 Years of Digital
by George S. Louis


Digital Systems & Solutions
Phone: 619-401-9876 and 888-588-9542 toll free

Text: George S. Louis, Esq., CEO

30 Years of Digital or Asleep at the Polarity Switch, a Conspiracy of Negligence and Hubris, and How the Entire Music Industry Killed the Music 30 Years Ago

The first time I realized the importance of polarity was in 1989 when I read about it in Clark Johnsen’s seminal book The Wood Effect.  From that point forward my approach to high fidelity was changed forever, and much to my greater listening pleasure I might add.  Clark clearly makes the case that comparing components or media with different relative polarities is a fool’s errand that could only lead one’s judgments astray both fidelity-wise and musically. Just in case my description of the problem of how music is being is being played too dense and wordy, here’s the bottom line.  I believe, and many other music-loving audiophiles now agree with me, that when a CD’s music meets your ear, approximately 85% of the time it’s going to be inverted.  This could be a major source of errors in the evaluations of media and equipment as well as result in a tremendous loss of fidelity and musicality which drastically reduces a listener’s ability to make the closest possible emotional connection to the music they love.  It almost goes without saying, the inverted playback of CDs greatly disadvantages them musically when compared to the non-inverted playback of their vinyl record counterparts.  Could this be a major reason why many listeners prefer analog to digital?

The common wisdom of the high-end audio community (that I hope this piece helps to change) is that the recording and music industry generally doesn’t pay much attention to polarity, and therefore, the polarity of media is pretty much distributed 50-50 between absolute polarity and inverted polarity.  The reason is thought to be because polarity inconsistencies can occur anywhere from the microphones (note microphone placement and reflected sound only results in phase differences at and between microphones but not their polarity) to the mixing boards, or from the mastering consoles to the final stamping of CDs, etc.  Consider the additional facts that the polarity of a given company’s media remains remarkably consistent over the years, although it’s quite likely that those same companies would have made numerous personnel, component, and stamping plant changes that we’d expect to be random.  But if the polarity distribution is closer to 85-15 (or 15-85 which way we don’t know for certain yet), then something more than random polarity mistakes must be the cause.  Therefore, it’s a statistical certainty that fundamentally nonrandom mistakes are made by a very high proportion of the recording and music industry.

There’s an appalling number of manufactures whose components are inverting who don’t inform their customers because either they aren’t aware of their mistakes or simply choose to ignore them and hope no one notices.  The list of components that invert but aren’t marked as such includes, CD players, DACs, speakers, headphones, and practically anything else I can name, including components with polarity switches and switchable polarity inverters that indicate the opposite polarity setting to their true polarity. It’s now become relatively common for reviewers to state the polarity of components they evaluate, yet I can’t remember a single instance where they’ve mentioned the polarity of the media they used for their evaluations; however, the polarity of the media has exactly the same affect on the fidelity and musicality, or lack thereof, as the polarity of the components, i.e. they both need to be correct or both incorrect in order to sound correct.  The reason I think it’s negligence and hubris in the music industry is because if either the producers of the media or the producers of the components listened to the way their media and components sound together, they should have known that there’s something rotten in the pits.

I relish the idea that subjective evaluations of fidelity and musicality will be shown on many occasions to be vastly superior to objective evaluations.  Only sound with compressions that differ from its rarefactions (asymmetrical) has audible polarity, because changing the polarity of identical (symmetrical) compressions and rarefactions doesn’t really change anything, so there’s nothing different to hear in the same way that’s there’s nothing different to see in the mirror image of a symmetrical object.  For more about polarity go to link to read a think piece about polarity.  I believe that anything we hear should ultimately be measurable; unfortunately we haven’t learned how to measure everything we hear. It now appears, after I’ve determined the polarity of over 3,500 CDs from hundreds of CD labels, that 80 to 90% of CDs (my best estimate is approximately 85%) are being played back inverted on CD players and on DACs that are ostensibly non-inverting including those with polarity switches.  And at least so far, what I’ve heard is, that except for test CDs and samplers with tracks from more than one label, all tracks on a single CD have the same relative polarity.  The good news here is that once you’ve determined the polarity of any track, you can set it and forget it, and I call that the Absolute Reality of Absolute Polarity.  It’s a bit complicated to sort out, but it appears most players and DACs frequently have an even number of inverting gain stages (and are supposed to be non-inverting) after their internal DACs, because most DACs have an I/V stage (current to voltage) on the DAC itself which inverts the analog signal which if overlooked could cause a mistake.  However, that’s only one of many possibilities as to how CD players and DACs might be unintentionally inverting.  It’s not so simple to know what the playback polarity is by listening, because how polarity is realized and heard can be the result of an inverted CD disc and inverting playback that’s net non-inverted or any of the three other combinations e.g. the CD isn’t inverted and its playback is non-inverting, that’s (non-inverted), a CD that’s not inverted but its played back inverted (net inverted), and an inverted CD with non-inverted playback (net inverted).  This is one of those rare cases where two wrongs really do make a right.  It also seems to me all standalone consumer and professional CD duplicators I’ve heard produce copies that are inverted relative to the copied discs, and that could be a major reason why many people think copies tend to sound better than original CDs.  Computer made copies aren’t supposed to be inverted unless the operator selects that option, but I don’t know if that’s always the case.

The polarity of discs made from a glass master standard test disc can’t be verified electronically until the glass master or a CD made from the glass master has been independently verified optically/physically.  In order to definitively determine if a CD player is inverting, we need to make a glass master with asymmetrical test signals that are checked optically to verify that its pits and lands conform to the CD Red Book standard.  When the glass master or a CD made from it isn’t optically verified to be correct, then just as above with CDs and CD players, there are two unknowns when checking its polarity electrically.  In which case two wrongs and two rights will make the glass master and CD made from it appear correct while a single wrong (either the player or the glass master or a CD made from it) will make the glass master and CD made from it appear inverted.  However, their may a stage in a CD player or transport where we could read and compare the bits of the raw data, (the raw data in itself has no polarity until it’s processed), we burned to a test CD, with the bits of the raw input data.  In that case we wouldn’t need an optically verified glass master or CD made from the stamper made from that glass master to create a standard test CD.

We can compare the relative polarity of a standalone CD or computer copies to the copied discs to find out if they invert copies.  But for the same reasons, as for CD players, we can’t know whether the polarity a copy made from the input of an external source to a standalone or CD copier is inverted relative to the copied disc, unless we know the output polarity of the input component. To test the relative polarity of the inputs to the outputs of standalone DACs and CD players’ digital outputs, we need a reference standard standalone DAC (RSD) of known polarity.  We can create an RSD by injecting a properly configured test signal into the DAC’s digital input.  Then we test the DAC’s analog output for agreement with the Red Book standard, and if it agrees we have our RSD.  We can’t know if a CD transport or CD player’s digital output is inverted relative to its analog output without an RSD.  Because as above, when testing CD players and DAC’s of unknown polarity, there are obviously two unknown variables.  Regardless of the polarity of the CD media, the CD player or the DAC being tested, when we use the RSD there’s only one unknown, so we’ll know the relative polarity of the tested component’s digital and analog outputs relative to the analog output of the RSD.  However, the testing of transports requires a CD of known polarity because the transport’s digital output polarity is unknown and even using an RSD only makes the combination of CD transport and DAC effectively into a CD player, and again as above, with a CD player it requires a CD of known polarity to establish its polarity.

Unlike the polarity of a vinyl record groove that’s relatively easy to verify optically, the digital information imprinted in the spiral track of a glass master isn’t laid down in a continuous pattern because of the Reed-Solomon cross-interleaved error correcting code used to make the disc’s playback less subject to errors caused by physical damage or contamination to the disc.  We can know what the pits and lands should look like because the Red Book standard explicitly defines their pattern on a glass master and a CD made from the stamper made from the glass master so they can be verified optically.  Since the digital signal’s 1′s are represented by the pit edges and the pits (the pits are bumps to the laser because CDs are stamped on their label side) and the continuous surface of the pits and lands between the pits are represent the digital 0′s, only the transitions from pit to land and land to pit are the digital 1′s.  So even if the stamper’s pits were somehow made physically reversed (convex instead of concave) it wouldn’t affect the polarity of the CD stamped from that disc.  I don’t know if there’s a digital polarity flag in the Red Book standard, but I’m sure an engineer who’s familiar with the Red Book standard could help us find out how so many CDs are made inverted.  CD-Rs and CD-RWs have no pits and lands, because it’s only transitions between areas of greater and lesser reflectivity that defines the digital 1′s so they’ll still work perfectly.

How is it that approximately 15% of CDs are played back inverted on those same CD players mentioned above?  Are they the CDs which are made inverted, or could they really be the non-inverted CDs, if it turns out that those same CD players and DACs that are supposed to be non-inverting, are actually doing the inverting?  We should find out the reason that hi-res online downloads may also be sometimes inverted.  I don’t have the technical expertise to make the relatively easy technical tests that would once and for all get everyone on the same digital page.  I hope we could work together to hear a second coming of CDs and digital in general.  Let’s try to solve the problem of inverted playback polarity which may be the biggest mistake in the history of audio. I believe for the last 30 years of digital technology, incorrect polarity has caused more grief for music-lovers and musicians than anything else I know of.  In my opinion the effect of absolute polarity on musicality easily trumps jitter reduction and all the “tricked out fancy” filters touted by the high-end component companies.  Whatever the ultimate causes of the huge disconnect between the makers of CD media and makers of CD players, 30 years with 85% of CDs being played inverted has lead to mistaken reviews, unnecessary equipment “upgrades”, and tweaks, resulting with a loss of musicality that shouldn’t be acceptable to any music-lover or musician.

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"High Fidelity OnLine" is an internet magazine, published since may 2004, devoted to high quality reproduction of sound and picture. It is a monthly magazine, but the articles are uploaded twice a month - in the beginning of the month and in the middle. The news column is updated on on-going basis, if possible. The main sections are: "Tests", "Events" (interviews, reportages, and similar), "Hyde Park" (user tests, opinions) and "Who asks..." (readers questions and HFOL answers). Articles from earlier issues can be read in the "Archive". Have a nice read!

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