There’s a problem that has been ignored by the entire music industry which I believe is really important to music-lovers that I think you might want to investigate. Approximately 35 years ago when digital media was introduced to the music consuming public as a media with “Perfect Sound Forever” the music industry made a huge screw up when it got the playback polarity of digital music on CDs and later DVD, etc reversed (inverted polarity). On a random basis that means that digital media and files are heard in the wrong polarity approximately 85% of the time and either 92% wrong or correct once their audio and video systems are set to a fixed playback polarity.
The bottom line is that the music played in inverted polarity sounds harsh and two dimensional which is probable the major reason that some music-lovers still believe (without knowing the real reason) that analog music media (which plays in the correct polarity over 99.9% + of the time and would also sound bad if played in inverted polarity) sounds better than digital media. And that often causes music-loving audiophiles to spend untold sums of money and time trying to smooth out the edgy and somewhat irritating and flat sound of digital media.
This should be an object lesson on how an entire industry with its experts and electrical engineers can get it wrong and not do anything about if for over 32 years and counting! So it should be an object lesson that the entire industry that creates recorded music and is based upon scientific principles continues to mostly get polarity wrong?
I've written two monographs that go into great detail about the problem at: http://www.AbsolutePolarity.com and http://www.PolarityGeorge.com . If you or anyone you know might be interested in developing The Perfect Polarizer™ that will detect and correct polarity in real-time, then please forward this email to them/encourage them to contact me, because I believe it could be accomplished with AI/App. Now, do you want to be part of the problem or part of the solution?”
George S. Louis, Esq., CEO
Digital Systems & Solutions
President San Diego Audio Society (SDAS)
1573 Kimberly Woods Dr.
El Cajon, CA 92020-7261
Its time to wake up and hear the music.™
Updated November 9, 2016 by The Polarity Project
Whether live or reproduced music consists of a series of compressions and rarefaction of air that are the sound waves we hear. Reproduced music is in absolute polarity when its compressions and rarefactions are in sync with the compressions and rarefactions of the original performance. Much of music’s sound waves consists of compressions and rarefactions that are asymmetrical. Scientific research has determined that below approximately 5 kHz most people hear compressions differently than rarefactions which means that for most listeners music that’s played inverted sounds different from when played non-inverted (in absolute polarity). All tracks on approximately 92% of compact discs (CDs) play in inverted polarity on approximately 92% of compact disc players (CD players or servers that they’ve been ripped to) which means polarity mistakes aren’t random (mathematically proved below). The converse of that is that approximately only 8% of CD players play all tracks on approximately 92% of CDs in non-inverted polarity (absolute polarity).
I suggest it’s a reasonable inference that the audio industry’s polarity determinations of digital components are inconsistent, because they may depend on who’s making the measurements. The deleterious effects of inverted polarity to sonics and musicality are the same whether it’s due to inverting components or inverted media. Although the polarity of components may be reported in reviews, the polarity of the media used in the reviews is never mentioned even though media polarity is variable and the exact same tracks are sometimes recorded in opposite relative polarity on different CD labels. Thus it seems that reviews of components are more about the musicality of hearing media in absolute polarity than the fidelity of components!
Playing music in inverted polarity rather than in absolute polarity (aka absolute phase) makes the sound brighter, harsher, more congested, less 3-dimensional sounding, and in general less musically and emotionally involving. It also makes the evaluation of the fidelity and musicality of media and components more difficult, and could be one of the main reasons that analog media, which is mostly in polarity, is judged by many music-loving audiophiles to be musically superior to digital media**. How to play most if not all digital media in absolute polarity is explained. Summing up in music-lover terms, 100% of listeners whose systems play CDs in absolute polarity when the polarity of the CDs are the same as the polarity of the CD player (the system’s net analog polarity is non-inverting) are hearing their CDs play inverted approximately 92% of the time and therefore aren’t able to enjoy the maximum potential emotional involvement with the music they love. Due to the on going nature of the research, you may check for the date of the latest revision to this monograph about polarity. High-Res discs and downloads aren’t exempt from polarity problems, but because I haven’t tested a sufficiently large sample, I don’t know what percentage are inverted.
The first time I realized the importance of listening in absolute 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 played inverted is 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 sound like it’s inverted and probably is being played 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 that the inverted playback of CDs greatly disadvantages them musically when compared to the non-inverted playback of their vinyl record counterparts. It should be noted that the polarity integrity of each element in the chain of a vinyl record’s recording through its playback can be determined without ever listening to it in a manner similar to that described below for digital media, but is much easier to accomplish for vinyl records than for CDs, because a record’s musical content is laid down continuously in its groove, which is fundamentally different from the discontinuous way the digital representation of a CD’s musical content is laid down in its track. Could this be a major reason why many listeners prefer analog to digital?** Sometimes there are additional reasons, that although substantially less significant, might influence some listener’s preference of vinyl records over digital media that you may read about below.*
I’ll elaborate further on acoustic polarity, but first I think this analogy might be illustrative for some readers. You write a doctoral dissertation on a computer and save it to a CD-R that you take to Office Depot and have them print copies to be hard bound for your committee. Office Depot does the printing and sends the copies to a bookbindery for binding and forwarding to your committee. When you appear in front of the committee to defend your dissertation you and they see white text on black pages. And although neither the text nor meaning of your dissertation has changed, now it’s surely a lot more difficult to read than if the text had been printed in the traditional black on white pages.
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 92-8 (or 8-92) 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. The polarity of Verve and Impulse! CD labels are an example of the music industry’s confusion about polarity. Two Diana Krall tracks on the Impulse! CD Love Scenes, Diana Krall CD are in the opposite relative polarity to the same two Diana Krall tracks on the Verve CD The Very Best of Diana Krall as determined by both subjective evaluation (listening) and objectively by comparing their waveforms with the Audacity Audio Editing Program on a MacBook Pro. If live microphone feeds of Diana Krall are recorded to a storage oscilloscope and compared to the Impulse! and Verve CDs of Diana Krall also recorded to the same storage oscilloscope, the tracks that match the polarity of the live microphone feeds were played in absolute polarity. And in fact some Verve CDs are in the opposite relative polarity to other Verve CDs and the same relative polarity as the Impluse! CD just referred to. I believe the Impulse! Love Scenes CD was issued in 1997 before Impulse! became part of the Verve Music Group in 1998.
I have two original CDs under the Justice Records label that's in Austin, TX with the title: Strike a Deep Chord Blues Guitars for the Homeless that are compilations with track #1 in one polarity and tracks 2 through 10 in the opposite relative polarity to track #1 but that's not unusual for compilations of cuts from different labels. Both CD boxes, booklets, and jewel cases have all the same information. The information on their matrix states that they're made in the USA and both have the same matrix legend: JR 0003 01! but all their tracks are in the opposite relative polarity. If nothing else, this finding surely makes a good argument for having a polarity switches on all digital components and once and for all sorting out the 30 plus years of confusion about the polarity of digital media and equipment!
It’s now become relatively common for reviewers to report the polarity of components they evaluate and sometimes even the electrical connections/acoustic polarities of a speaker’s individual drivers, 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, because 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. The bottom line is that most of the makers of digital media and playback components aren’t on the same digital page, and until they are, it’s a sonic and musical polarity crap shoot for those music-loving audiophiles who want to experience the greatest possible emotional involvement with the music they love.
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 click on Polarity Think Piece: A Speculation Regarding Perception of Detail or http://audiogeorge.com/polarity-think-piece-a-speculation-regarding-perception-of-detail/ 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% when the polarity of the CD player isn’t known, but approximately 92% of CDs play inverted on 92% of CD players, please see the New Polarity Math* at the end of this paper) are being played back inverted on CD players and on digital to analog converters (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 Analog to digital converters (ADCs), CD players, and DACs might be unintentionally inverting. In fact it could be something as simple as using the inverting input of an ADC converter(s) when recording the original performance or copying an analog recording and then not taking that into account when making the glass master. On the other hand, perhaps there’s a polarity flag for that’s being changed, but I’m not knowledgable enough about the CD redbook standards to answer that question. It’s not as simple as just knowing 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 it is 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 embedded in a music track to include meta data for the music track that might affect polarity and is checked with a very high powered optical or a scanning electron microscope 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 is inverted) will make the glass master and CD made from it appear inverted. However, their may be 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 or electron scanning microscope verified glass master or CD made from the stamper made from the glass master to create a standard test CD. Thus,ultimately, it can be determined to a 100% scientific certainty whether it’s approximately 92% of the CDs that are made inverted or approximately 92% of CD players that play inverted.
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 of 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’s 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 are 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 CD Red Book standard, but I’m sure an engineer who’s familiar with the CD Red Book standard could help us find out why 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 8% of CDs are played back inverted on those same CD players mentioned above? Are they the CDs that 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 that just might 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, because the emperors of audio have no ears/are afraid of how they’ll be judged when the polarity truth is finally the norm. 30 years of approximately 85% of CDs being played inverted has lead to mistaken reviews, unnecessary equipment “upgrades”, and unneeded tweaks, resulting in a loss of musicality that shouldn’t be acceptable to any composer, musician, or music-lover. And when the audio and music industry gets absolute polarity right, they won’t just be improving one audio system at a time, they’ll be improving everyone’s audio systems all at once.
*Here are some additional reasons that although not nearly as important as the polarity differences between most digital and analog media described above, sometimes makes comparisons of their sonic and musical differences more difficult than one might have thought. Some phono cartridges have more high frequency phase shift that frequency-specific delays the arrival of its high frequencies more than digital media. That tends to favor speakers with less than optimal time-alignment because their tweeters are mounded flush with its other drivers on a vertical baffle that’s perpendicular to the floor and results the speaker’s high frequencies arriving at the listener’s ears ahead of its midrange frequencies and comb filters with the speaker’s midrange and isn’t faithful to the phase response of the original performance.
Another reason is that recordings made with a Blumlein microphone technique that uses a coincident pair of crossed-figure-8 microphones (BLM) have out of phase high frequency crosstalk that puts the hall ambience/audience sounds into the opposite channel and out of phase. Many phono cartridges may actually make vinyl records that were made with BLM sound closer to the original performances than the original analog, 16-bit, or high resolution digital masters because their mechanical high frequency left to right and right to left channel crosstalk that’s out of phase may actually cancel some of the effects of BLM and thus be more faithful to the original performance. At one time I owned a Denon PCC-1000 stereo phono cartridge crosstalk canceller that was meant to heighten stereo imaging by compensating for the mechanical crosstalk of phono cartridges and thereby restore the original stereo imaging. It worked as advertised but unfortunately increased the noise due to less summed channel noise cancellation, so ultimately I didn’t like the tradeoffs.
*The New Polarity Math (NPM)
My beta testers and I have listened to hundreds if not thousands of audio systems whose polarity we didn’t know in advance. Included among those systems were those at both The Consumer Electronics Show (CES) and The Home Entertainment Show (T.H.E.) at Las Vegas in January 2009. Our empirical observations were that approximately 85% of the time the CDs they played sounded inverted. There’s only two ways that a CD can be played inverted on an audio system whose components are connected to be in absolute polarity, first, an inverted CD is played by a non-inverting CD player, and second, a non-inverted CD is played by an inverting CD player. Thus music-loving audiophiles try to wrap your ears around The New Polarity Math that dictates that if you don’t have any information about the polarity of a CD or a CD player, then the highest percentage that both the CDs and CD players can both be inverted and non inverted is either approximately 92% of CDs inverted and approximately 92% of CD players that aren’t inverted or the reverse, that 92% of CDs that aren’t inverted and 92% of the CD players are inverted, for the random result that CDs will be played inverted approximately 85% of the time. And if the polarity of the CD player is known and the playback system is set to play inverted, then CDs chosen at random would play in polarity approximately 92% of the time. But having said that, there are other possibilities for the percentages of CDs or CD players to be inverted, but since both CDs and CD player exhibit both polarities, whether it’s the CDs that are inverted or the CD players that are inverted, whichever is inverted must be inverted more than 85% of the time and the other must be non-inverted more than 85% of the time. Therefore, until it’s definitively established whether it’s the CDs or the CD players that are inverted, an inverting if one doesn’t have an easy way of changing polarity then if the amplifier to speaker wire connections (preferably at the speaker end) are set to the way that most CDs play in absolute polarity, then more than 85% and possibly as much as 92% of randomly chosen CDs will be played in absolute polarity. For the sake of the music manufactures of media and components may contact me for pro bono consultation regarding polarity etc.
If Eo = the empirically observed fraction of CDs that are played back inverted, CpN = the fraction of CD players that aren’t inverted, and CDi = the fraction of CDs that are inverted, then CDi = (Eo + CpN – 1)/(2CpN -1) and of course if instead of CpN you substitute CDn = the fraction of CDs that aren’t inverted, then the fraction of CD players that are inverted that we call CpI = (Eo + CDn – 1)/(2CDn – 1).
**Why the Polarity Mistakes Can’t be Random
If P equals the fraction of A to D converters or other equipment in the digital recording/playback chain that isn’t inverting, then 1 – P equals the fraction of that equipment that is inverting. If the makers of CDs or playback equipment randomly (half the time 50% = .5) made polarity mistakes, the fraction of digital recordings whose playback would be inverted equals .5 x P + .5 x (1-P) = .5 P + .5 -.5P = .5 (50%), but in fact it’s approximately 92% of CDs that playback inverted on approximately 92% of CD players. Therefore, polarity mistakes by the makers of A to D converters, CDs, CD players, and DACs can’t be random because the random result of .5 is independent of the value of P. Thus if you randomly set a CD system’s playback polarity (50-50), the system will playback 50% of CDs in polarity, but as explained above in The New Polarity Math, approximately 92% of CDs playback inverted on approximately 92% of CD players, so when in doubt, invert polarity because that will give you the highest probability (92%) of playing back in absolute polarity.
Conundrum: When John Atkinson technical tests of the first edition of the Cary Audio Design 303T Classic CD Professional SACD Player that accompanied the review by Michael Fremer in September 27, 2010 issue of Stereophile, his tests found it to be inverting (Cary Audio Design has assured me that they’ve made a firmware upgrade for the player that makes it non-inverting) at its both its single-end RCA and balance XLR outputs. I presume that he played a polarity test disc and observed a negative going signal(s) on an oscilloscope. The oscilloscope picture of the Oppo BDP’s polarity test show a positive going signal on both channels, and Oppo Digital insists that the BDP-95, BDP-105, and BDP-105D aren't inverting, yet it output is in the same relative polarity as the original “first edition” inverting Cary Audio Design 303T player! This is an example of the how confused polarity testing can be and the reason it needs to be nailed down once and for all in order that music-loving audiophiles may enjoy the greatest possible emotional involvement with the music they love.
In my opinion, another example of confusion about polarity is the Musical Fidelity X10-D Tube Buffer with its single tube that alleged purpose is for its high impedance input and a low impedance output to make a better impedance match between a digital source and analog component that it's connected between such as a CD player's or DAC's digital output and a preamplifier's analog input is really improving the sound of most digital playback because it's inverting not because of its impedance matching properties. And another component that's received excellent reviews but in my opinion plays approximately 92% of all tracks on approximately 92% of all CD in polarity is the Electrocompaniet EC 4.8, that seems to be based on a DVD player. It seems again that reviews hearing polarity but don't realize that's what they're preferring.
Email on March 20, 2012 between Emotiva Audio Corporation Customer Service and myself regarding the output polarity of their Emotiva ERC-2 CD Player
Dear Nick Kaumeyer,
From: OPPO Service
Date: January 24, 2012 4:02:09 PM PST
Subject: RE: BDP95 Stereo Polarity Result – FW: Audio Polarity
Below is an image to show the polarity test result for both L and R outputs (the audio processing parameters are kept as factory default):
We are using the “Dolby Digital Test DVD”, which contains a special signal for polarity test. According to the user manual, a positive pulse means the polarity is correct. So based on the oscilloscope’s screen snapshot, we can claim that both the L and R outputs on BDP-95’s Stereo terminals have correct polarity.
Please be aware that if you change the polarity for XLR terminals (Setup-> Audio Processing -> XLR Terminal Polarity: Normal/Inversion), the polarity for the above Stereo Outputs is also changed, since both the RCA Stereo and the XLR Stereo are using the same DAC thus the same analog signals. Please ensure that the XLR Polarity is set appropriately.
OPPO Digital, Inc.
2629B Terminal Blvd.
Mountain View, CA 94043
From: OPPO Service
Date: January 26, 2012 9:27:34 AM PST
To: “George S. Louis”
Subject: RE: BDP95 Stereo Polarity Result – FW: Audio Polarity
Unfortunately we can’t be of further assistance. Our player was designed to comply to the industry specifications, and the telemetries that we included in the previous E-Mail show that we are. Any discrepancy between what the manufacturing requirements and the authoring specifications are unfortunately not in our control.
On the BDP-95 you can change the polarity for the dedicated stereo and the XLR outputs, but there is no plan to support this on the multi-channel analog outputs or on our other products which lack XLR interfaces.
OPPO Digital, Inc.
2629B Terminal Blvd.
Mountain View, CA 94043
From: George S. Louis [email@example.com]
Sent: Wednesday, January 25, 2012 9:31 PM
To: OPPO Service
Dear Oppo Customer Service:
Thank you for the great oscilloscope picture of the “Dolby Digital Test DVD’s” polarity test picture from the Oppo BCD-95! I’d greatly appreciate seeing an oscilloscope picture of the same polarity test DVD played on your Oppo BDP-93 in order to compare the two pictures.
George S. Louis
On Feb 1, 2012, at 10:25 AM, OPPO Service wrote:
They are identical to the images that we showed. The core decoding aspects of the two players are identical, and with the player being set to NORMAL, the XLR, dedicated stereo, and the multi-channel analog outputs produce the same results. These results are also shared with the BDP-93 and older generation of players as well. We have never designed a player which had revered (inverted) polarity out of box.
OPPO Digital, Inc.
2629B Terminal Blvd.
Mountain View, CA 94043
From: George S. Louis [firstname.lastname@example.org]
Sent: Wednesday, February 01, 2012 9:56 AM
To: OPPO Service
Subject: Re: BDP95 Stereo Polarity Result – FW: Audio Polarity
Dear Customer Service:
Thank you for your very rapid and helpful response. That means that your players play all tracks on approximately 92% of CDs in absolute polarity. But I suspect that some other people’s polarity test discs will give them the opposite results, so they will think that your players are inverting. But if you’re correct, then all tracks on approximately al 92% of all CDs are made in inverted polarity.
George S. Louis, Esq., CEO
Digital Systems & Solutions
President San Diego Audio Society (SDAS)
Subject: Re: BDP95 Stereo Polarity Result – FW: Audio Polarity
Dear Oppo Service and Music-Loving Audiophiles:
To save verbiage and for clarity, hereafter I’ll refer to approximately 92% of CD players or DACs that play all tracks on approximately 92% of CDs in inverted polarity as an N-player or N-DAC, and the approximately 8% of CD players or DACs that play all tracks on approximately 92% of CDs in polarity (absolute polarity) as an R-player or R-DAC, in order for the CD player polarity designations to agree with the CD polarity designations. I’ll refer to the approximately 8% of CDs that play in polarity on R-players as an N-CD (so their polarity designations will agree with the polarity designations of The Polarity List), and the approximately 92% of all CDs that play inverted on the N-players as an R-CD. The Oppo BDP-95 that get rave reviews would seem to be one of the R-players at both its single-ended and RCA jacks and balanced XLR stereo outputs. So it’s no wonder that the Oppo gets rave reviews from the high-end audio press and music-loving audiophiles. There’s a January 2012 Stereophile review of the Emotiva ERC-2 CD player by Stephen Mejias the sound of which he liked and that just happens, according to John Atkinson’s test measurements in the April 2012 Stereophile, have of both its single ended and balanced outputs inverted. A February 2012 Stereophile review of an NAD C 515BEE CD player, and a Stereophile 2011 review of the “first edition” Cary Audio Design Classic CD 303T Professional SACD player and all of them were compared to CD players whose output polarity was the opposite of the particular reviewed player and in each case the reviewer preferred the player that was the R-player even when the R-player cost $6,500 against an N-player that cost $8,000 (the Cary Audio Design CD 303T versus their non-inverting CD 306). In each instance when the reviewer compared the player under review to a CD-R player the CD-R player was preferred. John Atkinson’s polarity test of the “first edition” Cary Audio Design 303T showed it to be a CD-R player. Cary Audio Design has since upgraded the 303T’s “first edition” firmware so that it’s now a CD-N player (plays approximately 92% of CDs inverted), which is I think is sonic and musical shame because it doesn’t have a polarity switch, so now it plays all tracks on approximately 92% of CD in inverted polarity (out of absolute polarity). In every case the reviewer reported that he thought the CD player that was used for the comparison sounded more analog like than N-CD players. In the July 18, 2008 Stereophile there’s a review by Art Dudley of the Sony PlayStation 1 CD Player where in it’s praised as sounding better in many ways than the $3,450 MSRP Sony SCD-777ES SACD and CD player. John Atkinson’s tests that accompanied the review reveal that its RCA jack’s output is polarity inverting and its composite audio outputs are non-inverting. And the Adcom models GCD-575, NAD M51 Direct Digital D/A Converter tested inverted by John Atkinson (Stereophile July 2012, and Audio Note CD-4.1x CD Player tested inverted by John Atkinson, "The CD-4.1x is a paradox: does it sound good because of how it measures or despite it?" Stereophile July 2012). CD players that also are inverting have all received very good reviews. It would seem that reviewers and the music-loving audiophile community aren’t preferring particular CD players as much as they’re prefer hearing CDs played in absolute polarity rather than in inverted polarity. Thus hearing music in absolute polarity might just be the most important factor in determining the fidelity and musicality of an audio system or at least a CD player! The Behringer A500 amplifier's single ended RCA input is inverting and its balanced XLR input in noninverting but there's no mention of that its user's manual and in my opinion the same is true of the Emotiva XPA-200 stereo amplifier.
I told PS Audio that I thought their DAC Link III was inverting and later when they tested it and confirmed my polarity findings. Subsequently, in a 2009 AudioXpress online a review by Gary Galo his technical tests noted that the DAC Link III’s analog outputs were inverted and I quote from the review “Please note that our new top-line D/A converter, the PerfectWave DAC, does not have analog outputs in reverse polarity. However, absolute polarity is switchable from the front panel so listeners may easily decide which they like best. Again thank you very much for the great review! Dave Kakenmaster Vice President of Sales and Marketing PS Audio aX.” But what PS Audio didn’t tell the reviewer was the only reason that the PerfectWave DAC included a polarity switch was that I badgered them into including one (That figures though, because I was born in Madison Wisconsin which is the Badger State). When I heard the prototype at 2009 CES I told them that I thought its polarity switch was labeled in reverse, and they called me after CES and thanked me for helping them get its polarity right.
But recently PS audio brought out their NuWave DAC that doesn't have a polarity switch and is also inverting, and yet neither in its specifications nor its owner's manual is its polarity mentioned. Paul McGowan told me that he knows that it's inverting and mentioned in a review in Hi-Fi News and Record Review as a warning to those do A-B comparison tests. At least Hi-Fi News and Record Review appreciates the importance of polarity.
Here's a recent email exchange between myself and the NAD Support Center:
|NAD M51 Direct Digital D/A Converter
Dear Mike/Technical Support Department:
Congratulations on the great review of your new NAD M51 Direct Digital D/A Converter by Jon Iverson in the July 2012 Stereophile.
I read that John Atkinson found it to be inverting when its polarity switch is in the non-inverting mode, so how did that happen, and are you going to change it? In the meantime I'd like to know how you test for polarity?
I'd like to audition an M51 in my own system in order to decide if I'd like to purchase one for myself to get the best possible sound from my digital media, so please tell me how I might do that.
Perhaps you'd find the information at the following links interesting and maybe even useful as a way to explain to your customers the reasons for having a polarity switch in the first place:
http://www.AbsolutePolarity.com and http://www.PolarityGeorge.com
George S. Louis, Esq., CEO
Digital Systems & Solutions
|re: NAD M51 Direct Digital D/A Converter
Thanks for pointing this out. We have now revised the software to correct the switch labeling. Owners can update the software, or just change the switch position. Because the polarity is switched in the digital domain there is no penalty of added noise or distortion for either switch position (this is not the case with analog designs where an extra stage of amplification must be used to invert). We included the polarity switch to correct for those occasional recordings that have it wrong. All NAD products are designed as â€˜non-invertingâ€™; this was a case of the â€œdyslexic software engineerâ€ syndrome. To try the M51 in your own system, please talk to or visit one our authorized dealers, many of whom have loaner programs or return privileges.
Director, Technology and Product Planning
I’ve listened to the Oppo BDP-95, Adcom GCG-575, Adcom GCD-600, and Adcom GCD-700 CD players which all were reviewed very positively yet they all sound and measure to be R-CD players. I listen to N-CDs and R-CDs to determine whether a CD player is an N-CD or R-CD player before using a polarity test disc to play their analog outputs into a line input of a Cricket receiver. And not to be overlooked are components with switchable oversampling/upsampling that may simultaneously be switching their output polarities without notifications to users. The Cricket has a green led to indicate normal polarity and a red led to indicate inverted polarity. In every case so far at least, my subjective polarity judgments have always been confirmed by subsequent testing with the Cricket. But just to be absolutely clear, my polarity judgements are only relative polarity judgments until a properly verified test CD is made and used as stated above. I’ve also found the Sony CD-990 CD, NEC CD-730, and NEC CD-830 CD players to be N-CD players. I’ll be adding CD players, DACs, speakers, headphones, and electronic components with analog inputs to The Polarity List of CDs that’s below.
How to Play Most if not all Digital Media in Absolute Polarity
Updated Dated January 23, 2015 by The Polarity Project™
You may use the list of some compact discs (CDs) below to set an audio system’s polarity to playback most compact discs in absolute polarity. As stated above, if you know the polarity of any track on compact disc, all its other tracks will be in the same relative polarity except for possible compact discs that are compilations of tracks from more than one label or possibly test discs.
In my experience the major labels are more likely to have CDs of both polarities but they tend to be predominantly one polarity and the list includes some of the CDs that are not in a label’s usual polarity. When the relative polarity of all the tracks on a label’s CD sampler is the same, it’s usually indicative of the label’s polarity for all its discs, because the sampler is probably representative of many of the label’s offerings. It may appear that the polarity of some labels CDs is random, e.g. Verve is an example of an umbrella label that has sub-labels that may have different relative polarities but each sub-label’s CDs are usually the same relative polarity. Therefore, each sub-label is listed as if it’s a totally separate label. If the CD isn’t silver (aluminum), e.g. gold it will be noted.
I’ve heard other labels with reissued CDs that have the left and right channels reversed relative to the vinyl record. Some stereo microphone and multi-microphone feed CD reissues have one or more feeds remixed into different channels. I’ve never heard a reissued CD even on a different label than the original CD that has its polarity different from the original CD.
The polarity designations are as stated only if the majority of CD manufactures are making CDs in correct polarity (N), but if the opposite is true, then the polarity designations should be reversed (R) but the relative polarities of the listings won’t change. Until it know whether it’s the CDs that are being made inverted or the CD players that are being made inverted as described in 30 Years of Digital and the 92% Solution at http://audiogeorge.com/30-years-of-digital-and-the-92-solution/, we won’t know what the actual polarity of the media is but only that an N designated CD will play in polarity on approximately 92% of CD players and an R designated CD will inverted on approximately 92% of CD players. You may read about how the 92% figure was determined at 30 Years of Digital and the 92% Solution or http://audiogeorge.com/30-years-of-digital-and-the-92-solution/. You may determine if a CD player is one of the 92% that plays most CDs inverted, by playing CDs to hear which polarity which the vast majority playback in. That assumes that you know that the rest the playback chain doesn’t invert polarity, but even you don’t know the net polarity of the rest of the system, at least you’ll know how to play most CDs in absolute polarity.
Phil Spector “Wall of Sound” (W/S) recordings are a special case because at both live and recorded performances Phil Spector wanted the lead vocalists and instrumentalists to be in absolute polarity (N), spotlighted in bas relief against a 2-dimensional wall of sound he created by having everything else heard in inverted polarity (R).
I’ve discerned the polarity of thousands of CDs but don’t think it’s useful to list them all. I can only determine the polarity of CDs by listening. I tried to list specific CDs and CD labels that are of particular interest to music-loving audiophiles. Because as the Perfect Polarity Pundit in reality I’m not always perfect, the list is subject to revision, so please feel free to suggest corrections and additions.
I listen to CDs on a player with a volume control and remote control digital domain polarity switch connected directly to a non-inverting power amplifier over a minimum phase speaker system of my own design. I discern polarity by deciding which polarity sounds more like live music. For SACDs, DVDs, internet downloads, and vinyl records I add a preamplifier with a remote control polarity switch. And for vinyl records I use a linear tracking turntable with a strain gauge cartridge. It also seems to me that some internet hi-res downloads are inverted.
For information on the sonic effects of polarity you may read A Speculation on Perception of Detail by clicking on the link: Polarity Think piece: A Speculation Regarding Perception of Detail, or http://audiogeorge.com/polarity-think-piece-a-speculation-regarding-perception-of-detail/. Given the relatively high proportion of audiophile CD labels that are polarity inverted including those labels with non inverted vinyl record counterparts, one might speculate that a major reason for the preference that many music-loving audiophiles for the presentation and musicality of vinyl records is that they’re comparing them to inverted CDs.
Anyone who’s interested in a free listening session sharing some of their favorite music/my favorite music/using my CD player’s remote control polarity switch to hear polarity differences for themselves, please email:email@example.com or call 888-588-9542 toll free 7-days a week from 9AM to 11:45PM Pacific time and I’ll do my best to accommodate you. And you may email corrections or additions for “The List” to firstname.lastname@example.org.
Because approximately 92% of compact discs (CDs) play inverted on approximately 92% of compact disc players (CDPs) one can set the polarity of a playback system to be correct approximately 92% of the time. There are several ways a system can playback in absolute polarity 100% of the time. A digital domain polarity switch of a CDPs or DACs or CD transport are the highest fidelity ways to toggle the playback polarity of digital media. The least convenient way to change a system’s polarity is probably is to reverse the hot and ground connections of all of a system’s speaker wires, either at the amplifier end of the wires or speaker end, but not both, because that would reverse the change of changing the wires’ connection at one end only. I recommend you try both ways to find out which if either sounds best. Changing a system’s playback polarity with a polarity switch on a preamplifier or on an integrated amplifier, or on an amplifier in the analog domain will also have the same basic effect. If a component has a balanced XLR output, there are adaptors that will reverse polarity and if the rest of the system following the XLR output isn’t balanced there are also XLR to single ended adaptors that opens up the possibility of switching polarity to more systems. Whichever way polarity is changed, it’s way, way, way better fidelity wise and musically than inverted polarity playback. So far at least, the only way to discern polarity of music is by listening, but it’s really true that little bit of practice with media of known polarity makes perfect.
Absolute polarity playback is better musically than inverted polarity playback in just about every aspect. But more specifically, absolute polarity playback relative to inverted polarity playback sounds, more purposeful, more rounded and convex rather than more hollowed out and concave, sounds fuller with more body, more organic/analog sounding, is less wooden/papery, less dry/more liquid, isn’t overly brittle, reedy, less hard/ragged/splashy/bright or overly detailed sounding, has more accurate timbre, is less congested, is more delineated/focused/holographic, has greater dynamics with better pace and rhythm, more virtual soundstage depth, and much better recovery of the ambience of the recording venue that facilitates the ability to suspend one’s belief that they aren’t experiencing a live performance. The better the recording, regardless of the microphone technique, from mono, to stereo, or multi-microphones, the easier it will be to discern polarity. The only exceptions are the Phil Spector “Wall-of-Sound” and “Reverse-Wall of Sound” recordings with artistic choices intentionally included mixed polarity, which allows listener’s to choose playback in the polarities intended or the opposite. The higher fidelity a playback system is in all respects, especially the flatter its phase response and group delay, the easier it will be to discern polarity over that system.
The benefits to be gained by playing a CD in polarity to improve a system’s fidelity and musicality largely depends upon whether the system satisfies the criteria described below. If the playback system doesn’t meet the criteria described below, it’s probably not worth taking the polarity of the system or media into account and you should probably ignore the entire issue of playback polarity altogether. But if you’ve read this far and also read my monograph, Polarity Think Piece: A Speculation Regarding Perception of Detail, at http://audiogeorge.com/polarity-think-piece-a-speculation-regarding-perception-of-detail/ you may feel that listening to music in absolute polarity in order to make the closest possible emotional connection to the music is important enough to make sure that your playback system meets the criteria set described below.
Regardless of which polarity the music is being played in, there are some necessary but not sufficient conditions that speakers or headphones must meet before changing polarity makes sense. All headphone or speakers drivers must have their drivers move in the same direction for an electrical signal of a given polarity whose frequency is in the speaker’s passband which is just another way of saying that the speakers and headphones are at least minimally phase-coherent [polarity consistent PC)]. Single driver headphones and speakers are at least polarity consistent because there aren’t any other drivers for them to be out of phase with. Systems with multiple drivers may be PC consistent if their crossovers are first order (6db/octave) or forth-order (24db/octave) crossovers or (n times 24 db/octave) that have all their drivers connected in the same electrical polarity. But second-order, (12 db/octave) crossovers require that drivers in contiguous frequency ranges be connected in opposite electrical polarity and are therefore not PC. The electrical polarity connection of drivers of other crossovers slopes in the analog (Gaussian domain) may or may not be PC depending upon the particular implementation. And digital crossovers with or without DSP can be designed to be PC. If a system’s speakers or headphones aren’t PC, the effect of absolute polarity or polarity switching changes is arbitrarily determined and inconsistent with the polarity of live music and recorded media because changing polarity 180 degrees only changes which drivers are in and out of polarity and which frequencies are in or out of polarity. And of course there’s no correlation between non-PC polarity and the polarity of recorded or live music. If I had non-PC headphones or speakers, I’d replace them in order to hear the benefits for fidelity and musicality of playback in absolute polarity.
**There's also the Gibbs Phenomenon of lowpass filters that results in both pre and post ringing of the transient digital signals. New digital technology such as apodising filters have made significant changes to the pre and post ringing characteristics of digital low pass filters that may help mask the audible effects of the Gibbs Phenomenon but not eliminate them altogether by eliminating pre ringing that doesn't occur in nature while increasing post ringing that's more "natural sounding", and some digital filters claim to eliminate all but one cycle of pre and post ringing on transients. On the other ear, all magnetic based phono cartridges have inductive reactance (reactive capacitance for capacitive phono cartridges) that results in their outputs ringing. Thus strain gauge phono cartridges that are mostly resistive are potentially are higher fidelity reproducers of vinyl records. I would suggest that if a strain gauge cutter could be used to cut the master for vinyl stampers, then records might be even higher fidelity and more musical. Of course the same might be said for speakers and microphones that use magnetic or capacitive fields to move their diaphragms. But perhaps at some point will our ability to ever approach high fidelity exceed our ability to discern differences between reproduced music and the real thing?
Updated April 13, 2015
When a CD is made in normal (absolute) polarity (N), a non-inverting playback system will play the CD such that its compressions and rarefactions are in sync with the live performance. When a CD plays inverted, the compressions and rarefactions of a non-inverting playback system will be exactly out of sync with the live performance.
N = Normal Polarity for approximately 92% of CD players, R = Reversed Polarity for approximately 92% of CD players, BP = Both Polarity CDs, W/S = Wall of Sound, S/W = Reversed polarity Wall of Sound, MT = Tracks with different relative polarity, i.e., some N and some R tracks, MP = Mixed polarity on one or more tracks. MN = Mostly Normal Polarity, MR = Mostly Inverted Polarity. Usually reissue labels such as Mobile Fidelity don’t change the polarity of the original CDs so their polarities are dependent upon the polarity of the label of the original compact discs. I only list the polarity of the CD layer on Hybrid SACDs, but I expect the SACD layer’s polarity is the same as its CD layer. A “The” at the beginning of a label name will be omitted for the purpose of alphabetizing but shown in parenthesis after the label name, e.g., (The). To save verbiage and for clarity, hereafter I’ll refer to approximately 92% of CD players or DACs that play all tracks on approximately 92% of CDs in inverted polarity as an N-player or N-DAC, and the approximately 8% of CD players or DACs that play all tracks on approximately 92% of CDs in polarity (absolute polarity) as an R-player or R-DAC, in order for the CD player polarity designations to agree with the CD polarity designations. Because the actual polarity (as apposed to relative polarity) of analog components such as speakers, headphones, and electronic components with analog inputs can be determined their actual polarity will be designated as N for non-inverting and R for inverting, i.e., the same plus underscoring. High-Res discs and downloads aren’t exempt from polarity problems, but because I haven’t tested a sufficiently large sample, I don’t know what percentage are inverted.
Disclaimer: The ideas expressed herein are the opinions of the author and therefore their value and truth should be determined by the readers for themselves.
George S. Louis, Esq, CEO, Digital Systems & Solutions, Phone: 619-401-9876, 88-588-9542 toll free, Email: AudioGeorge@Audio George.com, Website: http://audiogeorge.com
It all began with John Atkins
on’s gratuitous comments in the Measurements section of his review of the KEF R700 speakers in the November 2014 Stereophile (p.103). The comments I’m referring to are, “… In the time domain, the R700’s step response on the tweeter axis (fig.7) reveals that the tweeter and woofers are connected in positive acoustic polarity, [I call electrical polarity] the midrange in inverted polarity. Some internet know-alls have opined that this mixture of polarities is a problem. It isn’t. [And as you’ll see I take great umbrage with that opinion as well as his other pronouncements.] What actually matters is that the decay of each drive-unit’s step smoothly blends with the start of the step of the unit nest lower in frequency. In this case, this results in the superb frequency-domain integration of the R700’s outputs seen in fig.4….”
I responded with a letter to the Editor and there’s a reply in Stereophile by John Atkinson that you may read below. And for what it’s worth, in my opinion all tracks on all Stereophile music and test CDs with music, one of which includes a test track for determining the absolute polarity of one’s system, play in inverted polarity on approximately 92% of compact disc players! Therefore, anyone relying upon Stereophile’s test CD, Reference Recordings music and test CDs, or Sheffield Lab CDs, for that matter, because they all get polarity wrong on approximately 92% of compact disc players, to determine/set their audio system’s polarity, will get the playback polarity correct for approximately 92% of CDs and wrong for almost 100% of vinyl records which almost always play in absolute polarity (please see: www.AbsolutePolarity.com for an explanation of the reason for those percentages) . I encourage all readers to listen and decide for themselves. “ And because there won’t be any correct polarity for music heard over a non-phase coherent speaker such as KEF R70, in my book, that automatically disqualifies it as worthy of being a called a high fidelity speaker.
In his measurements of the KEF R700 loudspeaker in September (P.103), John Atkinson stated that he thinks people such as myself, who believe that it’s important for all of a speaker’s drivers to be in the same electrical polarity to be a truly high-fidelity speaker, are mistaken. I’ll shamelessly stand behind that statement, regardless of anyone else’s opinion to the contrary, because live music doesn’t have some frequencies arbitrarily inverted. And since JA measures and reports the polarity of components, and in this case the electrical polarity of the drivers, is implying that his reports of those specification are really meaningless? If so, why does he measure then/report on them at all?
--George S. Louis AudioGeorge@AudioGeorge.com
“There is a hierarchy of measured performance, Mr. Louis, of which absolute phase/polarity just one parameter. All research into loudspeaker sound quality shows that listeners prefer the sound of a loud speaker with a flat amplitude response but whose drive-units are in opposite polarities, to one in which all driver are in correct polarity but the response isn’t flat.
If the response is flat, then listeners will prefer the sound when the drivers are in the same polarity. However, with second- and third-order crossovers, which for practical reasons are the most common, you cannot have both of these factors correct. The designer must choose one, and the best choice, in order to satisfy listeners, is to abandon absolute polarity. —John Atkinson”
You may take note that John Atkinson never directly addressed my claim, that some speakers shouldn’t be considered “high fidelity”because they don’t have all their drivers connected in the same electrical polarity, i.e. it’s a non secquitur. My rejoinder is obviously too long for a letter to the editor, so I suggested that it be published as a guest editorial/think piece. But won’t be published per the email of December 4, 2014 from John Atkinson as follows:
“Thank you, George. However, I don’t think more discussion of this subject on our “Letters” column is warranted. You had your say; I had mine. – John
“Letter to the Editor/Guest Editorial/think piece
Dear Editor (John Atkinson),
I was pleasantly surprised to see my Letter to The Editor in the November issue and that it was deemed worthy of John Atkinson’s response. I agree with his astute observation that in most audiophiles' hierarchy of fidelity the linearity of a speaker's frequency response will almost always trump the electrical polarity of its individual drivers as well as its overall acoustic polarity and any of a speaker's other measurements. As he correctly pointed out, speakers with second/third-order crossovers regardless of whether they’re passive or active-electronic, can't have all their drivers connected in the same relative electrical polarity and at the same time have flat response. For most in-home speaker systems which aren’t designed to reproduce the full volume of a live rock concert or full classical orchestra, etc., third order crossovers are the highest order in common use. For this reason, the use of fourth and higher-order crossovers is usually reserved for those applications where a speaker’s drivers are frequently subjected to the immense if not the prodigious power input required to sustain the continuous high sound pressures that are often required for the power hungry venues of public address systems/the sound reinforcement of open-air concerts. Higher order crossovers because of their steeper roll off slops decrease a driver’s audible distortion by increasing its power handling capability at and around its crossover frequencies where its ability to absorb power begins to diminish. Increasing the power handling of a driver commensurately reduces the risk of worst-case catastrophic failure due to its coil shorting/burning out. A fourth-order crossover must have al its drivers connected in the same relative electrical polarity in order to achieve flat amplitude response, but there’s no free engineering lunch because the higher the order the crossover the greater its group delay. Due to the constraints of space and time I’m deferring discussion of fourth-order crossovers higher than forth-order. I’m pretty sure John would agree that the audibility of that deficiency isn't likely to replace a speaker's linearity as the number one priority in most audiophiles' hierarchy of fidelity. While I'm at it, since the devil’s in the details, just in case you’re not already aware of it, only crossover-less speakers/first-order crossovers have the potential for transient perfect response, but only at a listening point(s) where all their drivers are time-aligned.
With that in mind, a number of loudspeaker manufacturers, e.g., Vandersteen, Thiel, and Von Schweikert, just to name a few, use first-order crossovers with all drivers connected in the same relative electrical polarity, make sure their speaker's acoustic polarity is correct, and time-align the speaker's drivers. In the mathematical theory of analog only crossover filters it's axiomatic that for linear amplitude response the drivers must all be time-aligned to insure there’s a sweet spot where all frequencies arrive in sync When a speaker’s drivers are concentrically mounted coincidently on a single axis the sound of each driver will be time-aligned at every point in space and by themselves can’t comb filter. But those listeners who’d prefer not to be exposed to the harshness of the sound at those places where the left and right channels comb filter each other, must make sure they’re always positioned equally distant from the left and right speakers.
Despite what some speaker designers would have us believe, it isn't possible to time-align a speaker's drivers through an analog only crossover. Speakers whose drivers aren't time-aligned comb filter the acoustic output of the frequencies that pass through the overlapping frequency region(s) of the speaker's crossover adding harshness to the sound. But the story of modern crossover design doesn’t abruptly end there, because many crossover designer is holding some digital wild cards up their up their collective digital sleeves. And when they play those digital wild cards we’ll find ourselves immersed in entirely new audio sound fields that engenders properties the sound of which we’ve heretofore undreamt of. DSP comes with a seemingly spooky ability to realize frequency independent fixed time delays and make relative speaker amplitude adjustments to time-align all a speaker’s drivers to an arbitrary location in the listening room regardless of where/how the drivers are mounted on a speaker's cabinet/super structure. Potentially DSP could work its "magic" by incorporating technologies that emulate the functionality of the Xbox 360 Kinect Sensor or other technologies that enable the speaker's sweet spot to follow the listener's movements so regardless of their location they'll always be positioned at an optimized listening point. Now that a speaker engineers’ tool box includes DSP, we should be careful not to become so jaded that we take for granted DSP’s digital magic tricks and sonic treats that not all that long ago, were only the stuff of science fiction lest we forget how greatly that’s increased the fidelity and musicality of speakers.
DSP will never satisfy the "analog only crowd," because all analog signals are converted to digital for DSP. Single driver headphones may provide a work around the objections of digiphobes because within their limitations, they ape the sonic feats of DSP, and don’t add comb filtering to the sound because a single sound source can’t comb filter with itself. Alternatively, if one doesn’t enjoy listening to music over headphones they could try placing their speakers face-to-face, sit between them, and experiment with their positioning in order to hear if there’s a distance from their ears that sufficient to satisfy their musical sensibilities. Put analog binaural dummy-head recordings on your audiophile listening plate, and you’ll essentially have the benefits of DSP without the digits.
The speed of sound is the same at all frequencies; therefore, at live performances all frequencies of any particular instrument/voice arrive in absolute polarity and time-aligned at the listener's location/coincident-pair microphones. Individual instruments/voices approximate point sources so individually their sound arrives time-aligned at each of a listener’s ears and any coincident-pair of microphones regardless of where the listener is seated or where the microphones are positioned. And If you’re keeping score, the inherent time-alignment and absence of harshness a coincident pair of microphones brings to the music table is a huge advantage for them over every other microphone technique, except for microphone setups where no two microphones receive the sound of the same instrument/voice. Other than the aforementioned special case, every other arrangement of microphones is disadvantaged because they add the unwelcomed harshness of comb filtering resulting from the microphone’s outputs being combined during the mixing of the recording’s master. That said, comb filtering of massed instruments and voices is an inescapable characteristic of their sound at live performances. So for that reason alone, I’m suggesting that recordings of massed instruments/voices aren't particularly well suited for the evaluation of a system's time-alignment/fidelity. And as if that’s not enough the interaural spacing of our ears means that whether we’re at a live performance or listening over speakers we’re always subject to the affects of comb filtering. When we seek the highest possible fidelity we should avoid using speakers that by design add comb filtering to the sound by doing our best to minimize comb filtering, short of cutting off an ear.
I've concluded, as have many audiophiles, that all tracks recorded on the majority of digital media such as compact discs, SACDs, high-res audio discs, and digital files play in inverted acoustic polarity on the majority of CD players, SACD players, servers, and DACs. Therefore, we'd like a polarity switch (preferably remotely controlled) on all digital playback components to correct for inverted components/media, and it wouldn't hurt to have polarity switches on analog components either. We believe that most people who listen over phase coherent speakers or headphones prefer to hear music played in absolute polarity. But again, that's probably less important to most listeners than deviations from linear frequency response. However, for higher fidelity, having both linear frequency response and absolute acoustic polarity would be better yet!
So, why should audiophiles suffer the pronouncements of the self-anointed arrogant audio gurus whose conspiracy of ignorance and hubris in their unabashed chutzpah and techno- hype demagoguery would have us consider those speakers whose designs the science of acoustics have proven critically flawed have us consider them to be truly capable of high fidelity? The answer is they shouldn't, because they're not! In other words, since the laws of physics are the same for every speaker designer/manufacturer, you shouldn't expect any time in the foreseeable future to find out that someone/company has cornered the market for properly designed speakers, their hyperbole and disingenuous straw-man arguments to the contrary, notwithstanding. Lest you forget, the audiophile cheese is only binding if you swallow it. Ultimately, I think that it all comes down them doing a little tinkering around the edges of exotic driver/cabinetry/materials/construction with a lot of remarkably outrageous claims thrown in for good measure.
Linear frequency and correct polarity in and of themselves aren't enough to guarantee true high fidelity, and for that reason a great many additional elements of a system's performance must be optimized before it's worthy of the label "true high-fidelity." I hope the very talented creators of high fidelity in their eternal quest for perfect sound not only insist on absolute polarity and flat response but also strive to maximize the fidelity of all parameters required for true high fidelity. Fortunately for audiophiles, deviations from measurably perfect fidelity aren't equally audible to every listener. Therefore, at some level of less than perfect fidelity, it should be possible for nearly everyone to become emotionally involved with the music they love. Be aware though, it comes with some caveats. It’s likely to be sooner rather than later, that you'll embark on the upgrade path to increase the fidelity and musicality of your system. Not too long after the adventure of your audiophile journey has begun, probably the first thing you'll notice is regardless of how minor incremental improvements seem at first the more you listen the more difficult it will be for you to go back. Because no matter how great you felt your system sounded pre upgrade(s) it will have become "so yesterday's hi-fi", and going back won't be an option. As your fidelity intelligence sophisticated increases the intervals between successive upgrades decreases, so if you're not careful you'll become so fixated on upgrading and tweaking that you're no longer emotionally involved with the music, which is antithetical to your system's raison d’être.
George S. Louis, Esq., President of the San Diego Audio Society (SDAS)
Disclaimer: The ideas expressed herein are the opinions of the author (expressed under his First Amendment rights) and therefore their value and truth should be determined by the readers for themselves.”
© 2014 George S. Louis