Yep.
You may or may not hear a difference.
You may or may not hear a difference.
Preamp inverts phase question:
The owners manual of my preamp indicates that the preamp inverts phase: the circuit is phase inverting. Does this mean that I need to hook my speaker cables up backwards to correct the phase inversion... do I hook the positive speaker cable to the negative speaker binding post and visa versa with the negative speaker cable connections on both speakers?
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My Calypso has a phase inverting feature which can be switched with the remote. Is this similar to your preamp. If it is the purpose is to be able to shift phase because some music is recorded out of phase (by accident ?) and sounds better played back out of phase. Most of the time when I shift phase to check it doesn't make a difference. |
The purpose of phase in a speaker is to make sure that all the speaker's all push out and pull back together. when speakers are out of phase, one speaker is pushing air into the room when the other is pushing away from the room...and that cancels out the sound. It's like two sine waves where one speaker is all the way plus while the other speaker is all the way minus. For hifi systems (stereo or Home theater), as long as all the speakers are wired the same way, it doesn't matter .... all of the speakers will be in the same phase. It doesn't matter which is plus and which is minus as long as all the speakers are wired that way. |
For hifi systems (stereo or Home theater), as long as all the speakers are wired the same way, it doesn't matter .... all of the speakers will be in the same phase. You are referring to what is called relative phase, which means that the connections assure that both speakers are moving in the same direction at the same time. If relative phase were to be incorrect, the symptoms would be extreme and obvious -- vague diffuse images, poor bass, etc. The original poster is referring to what is called absolute phase, which refers to the outputs of BOTH channels being inverted in phase with respect to the program source. That will have sonic effects which are subtle, but will definitely be audible to some people listening to some recordings on some systems. Particularly on sharp transients, where the leading edge will have the wrong polarity (the ear being particular sensitive to the leading edge of transient waveforms, compared to what follows during the next fraction of a second). An inversion of absolute phase in a preamp or power amp can and should be corrected by reversing the positive and negative speaker leads on both channels. It would be more problematical if the inversion were in a source component, because correcting it for that component would create a similar problem for the other source components. Regards, -- Al |
I don't think one's ears can discern the phase of an orchestra or an instrument in an orchestra...and each instrument, each violin, definitely play in and out of phase with each other. So I am not sure how one would record in a way that kept the phase "accurate", given that each time a musical piece is played, the phase of any instrument on any note or transient is random. A specific recording might sound better with one absolute phase rather than the other, but the next recording (or cut on the cd) could sound better with the other absolute phase. What am I missing? |
Almarg, So...then it's a 50/50 shot as to which phase to use; by reversing my positive and negative speaker leads (correcting the absolute phase inversion) some recording will sound better but, some may sound better with an inverted absolute phase. What then is your recommendation: to correct for absoulte phase or to allow the phase to remain inverted? |
Easy test. Play a dozen LPs, CDs, and/or reel-to-reel tapes. After you listen each one, switch the speaker connections left-to-right (+ to -, red to black, whatever) on both speakers. Play again. Do you hear any difference in any of them? If not, count your blessings and forget the whole thing (because your speakers do not reveal polarity* differences). If you do hear a difference, then decide if it's important enough for you to keep switching speaker cables or invest in a polarity-switching preamp like the Aesthetix Calypso. * I think of this as polarity switching rather than phase switching, but it's probably best not to get into that. |
On typical poorly recorded, heavily multi-miked, heavily processed material, absolute phase (or polarity, as Dopogue points out) will clearly make either no difference or a random difference. On string instruments, and many other instruments as well, I'd imagine it would also make no discernable difference, as Ghstudio points out. However, on a high-quality audiophile caliber recording, that is done using just two or three microphones, that is minimally processed, and especially one that contains sharp percussive sounds, you can find many comments by equipment reviewers and others indicating that there will be subtle but audible degradation if polarity is inverted. As Dopogue alluded to, some preamps even provide for on-the-fly polarity switching via remote control. My own philosophy has been that it's easy enough to keep the system phase correct (unless, as I mentioned previously, the source components differ from one another), so I just do it and don't worry about whether or not having it wrong would make a difference. Regards, -- Al |
Adampeter, Here is some reading material that backs up what Al has been saying. Stan Ricker Absolute polarity, How important? . |
I'm sorry, but phase really does matter and is very important. The difference is very apparent to me when using a phase inverting phono preamp. Why just assume that some recordings may be phase inverted, so it doesn't matter. You should configure your system to replay music properly, and that means switching the cables at the speakers to compensate for the preamp being phase inverting. Let the recordings that are "wrong" be wrong and let the ones that are phase correct play back properly. It is silly to set up the system "wrong" because phase might not matter. Set it up properly and let the chips fall where they may. |
It only matters, Hifiharv, if it's audible. I could never hear polarity differences ("normal" vs "inverted") until I got my current speakers (Gallo Reference 3) which the manufacturer says "are very polarity sensitive." Most of my friends' systems are not polarity-coherent and it's pointless for them to mess with it if they can't hear it. Dave |
Your question was not entirely clear, which may partially account for some of the complicated answers. When you say that your preamp is "phase-inverting," do you mean that it has a control switch or button that lets you go back and forth from normal phase to phase inverting? I suspect that that is what you mean, though your question could be interpreted as meaning that your preamp is always phase inverted. Assuming that you have a switch or button on the preamp and/or remote control that lets you toggle between phase and phase-inverted, then don't reverse the speaker wires. Connect amp positive to speaker positive, and amp negative to speaker negative. Then, when playing music, you can toggle back and forth to see if you prefer normal phase or phase inverted. Many people can't hear a difference, though you may be one who can. In all probability, your problem is really a non-problem, despite some of the replies to your question. Something of a complication might enter if you connected your sources, preamp, and amp in balanced mode (XLR connectors) and some of your electronics are American (pin 2 non-inverting or positive) and some of your electronics are German or Japanese (pin 2 inverting or negative). In that case, your electronics would be out of phase. There are various ways of restoring phase in such cases. |
Victor Khomenko of BAT claims that 50% of recordings are recorded out of absolute phase. If true, it would make your question a mute point. However, I would switch the + and - leads at the amplifier end, as I have done in my situation. My preamp also inverts polarity, and the manufacturer (VAC) recommends switching the leads at the amplifier instead of at the speaker terminals. You can always experiment on your own, and no damage will be done. Cheers, John |
Most think that inverted and non inverted options on preamp is for switching back and forth for certain recording, although one can do this and it can have an affect, this is not the true nature of what it is for. It is about matching components! If your preamp is inverted then you should be (in a perfect world) using an amp that is non inverted. Like wise if your using a preamp that is non inverted, then you want an amp the is inverted. When there is a mismatch that is when reversing the speaker wires will solve the problem. On some systems it will be noticeable on others, not so much. I have found when setup properly it can affect sound stage and bass, listen to female vocals will have more depth as well. |
Benie, again, since many discs are recorded in mixed polarity and the rest are half "normal" and half "inverted," I don't think your argument holds water. On the mixed discs, the polarity setting doesn't matter ( although I have discs where I can pop the vocalist out front with one polarity setting and push him back into the mix with the other). Only a polarity switch or speaker cable switching will "fix" the others. The electronics are basically inconsequential. And the speakers -- the way they're wired internally -- are key to whether the effect is audible or not. |
01-08-09: Polk432 I agree that following the manual is fairly important, but running 'out of phase' will not endanger the unit in any way. It will not damage the preamp, or shorten it's life at all. It's a sonic thing only. If you can't hear the difference, then swap the speaker cables as suggested. I have heard it on some recordings, and I wish my preamp had a phase invert switch, as I felt that useful on occasion. Cheers, John |
If my preamp inverts and my amp is non inverted then there is no need to correct the phase is that correct? No, that is wrong, and what Benie indicated has no basis as far as I am aware. Whether the amp and preamp are individually phase inverting or not is of no significance; what matters is the overall system response. The idea is that the polarity of the source material should be the polarity that is fed to the speakers. Also, I must say that I am surprised that this thread has produced so much discussion of whether or not absolute phase/polarity makes an audible difference. Just make the system polarity correct, and whether or not polarity makes an audible difference on your system with your recordings then becomes irrelevant. If it does make a difference, your system will then be optimized for best results on those recordings on which it is likeliest to make a difference (audiophile-caliber, simply mic'd, minimally processed recordings, particularly those containing sharp percussive sounds). If it doesn't make a difference, then nothing will be lost by connecting that way. It's as simple as that. Regards, -- Al |
"[If my preamp inverts and my amp is non inverted then there is no need to correct the phase is that correct?]" Yes that is correct! Whether you hear a difference or not. This is the correct way. Dopogue wrote "( although I have discs where I can pop the vocalist out front with one polarity setting and push him back into the mix with the other)." It sounds like your system is very revealing and you have ears that can hear it. Some systems are not and some ears can't. As I said, one can hear a difference on some recordings, but that is not the primary purpose. From a technical design stand point having the components properly setup with either Non inverted and inverted or inverted and Non inverted, is the primary affect. The phase of the recording is secondary. Some designers agree with this, there may be some that don't, who knows. But what ever way works for you, go with that. |
"[If my preamp inverts and my amp is non inverted then there is no need to correct the phase is that correct?]" Can you kindly offer either a technical explanation for that claim, or a link that would provide one? I don't see any basis for that claim whatsoever, as I indicated above, and I have never heard such a claim before. Regards, -- Al |
I'm not a tech, are you? But I have had it explained to me by a very highly skilled Designer and I don't mean someone into DIY. As far as a article about: Google is your friend! Can you kindly offer either a technical explanation saying how I might be incorrect, or a link that would provide one? I am not talking about, Recording or Speakers!!! Thanks. |
I'm not a tech, are you? Since you asked, I have both Bachelor's and Master's Degrees in Electrical Engineering, and more than 30 years experience as an electronics circuit designer and manager (although not in audio). I also have close to 30 years experience as an audiophile, and I am widely read on the subject, including high end publications (TAS, Stereophile, etc.), mainstream publications, the Journal of the Audio Engineering Society, etc. I have never in all that time encountered the claim you have made, that inverting preamps work best with non-inverting power amps, and vice versa. By that logic, every properly set up system should invert absolute phase/polarity overall. That conflicts with everything that has been written indicating that maintaining absolute phase can be important in some systems with some recordings, to a subtle degree. You can start with the papers that Jea linked to. I understand that you are not talking about the recording or speakers. You appear to be saying that somehow a preamp/power amp combination will function best together if the combination of the two components is inverting. As I say, in all of my experience that I cited above, I have never encountered such a claim. Likewise, I have never encountered any claim that having a combination that is non-inverting is necessarily better, either, other than the fact that it maintains the polarity of the recording without having to interchange speaker connections. So I don't think that asking me to provide a link that will "prove a negative," so to speak, is quite a fair question. Questions that have no basis tend not to be discussed. Regards, -- Al |
I agree with Almarg and Zargon. In my case, I have an American pre and a German amp. To run them in balanced mode while preserving polarity, I bought an interconnect that had the XLR pins reversed at the factory (2 to 3 and 3 to 2). That works very well, and I have not had to reverse speaker cables or otherwise fuss with the system. The cable manufacturer, by the way, was quite familiar with my problem and how to correct it, and reversed the XLR pins at no additional charge. |
I concur with both Almarg and Zargon, Bernie is incorrect. Once the phase is inverted, it does not magically 'uninvert' on it's own. If the preamp inverts and the amp inverts, then you are back to absolute phase. One more option could be an inverted source. An inverted source with an inverted preamp and a non-inverting amp would also produce absolute phase. To make it simple, think of absolute phase as a '+' and inverted phase as a '-' . 2 X '-' = '+' , 1 or 3 X '-' = '-' . You can simply change the '-' to a '+' by switching + and - on your amp terminals, no big deal. Of course since 50% of recordings are recorded out of absolute phase, it really shouldn't matter at all. Cheers, John |
:-) lol Jmcgrogan2 wrote "One more option could be an inverted source. An inverted source with an inverted preamp and a non-inverting amp would also produce absolute phase. To make it simple, think of absolute phase as a '+' and inverted phase as a '-' . 2 X '-' = '+' , 1 or 3 X '-' = '-' . You can simply change the '-' to a '+' by switching + and - on your amp terminals, no big deal." Thank you very much for taking the time to explain it instead of just saying it. Very well put in easy to understand terms. This explains why I am correct for my system and not for others. There must be many others that have sources that are inverted and then throw in phono pre's and DACs on top of that as well. I could not change the speaker cables on my speakers. I run Acoustat's with the Direct Drive Tube Amps so I had to get a switch put in a preamp to be able to switch in between inverted and non inverted. This is an area where an Electrical engineer would be more versed as there are absolutes. Sorry to say it but I just don't hold Electrical engineer to the same standard as I once did or some so called online Electrical engineers . I just seen to many of them saying certain things are impossible when it comes to cables and such. For me it ruins some of the credibility because I hear a difference! Maybe I was confused when the Designer explained it to me as it may have been just to my system he was talking about. But as to my other points as to how it affects the sonics and sound stage, I can hear it. I believe I am I still correct in believing that a designers primary function when designing with inverted + non inverted components is the objective for the components to match, so one can achieve absolute phase. |
Benie, you're still missing the point that with respect to absolute phase (polarity), you are essentially at the mercy of the recording engineers and how any given disk was recorded in the first place. It would be wonderful if all disks were recorded in absolute polarity, but they're not. For instance, every Deutsche Grammophon record and tape I own was recorded in "inverted" polarity. So the only way you "can achieve absolute phase" when playing a DG disk is to switch speaker cables or have a preamp with a polarity switch. IF, as I keep saying, you can hear the effect at all. |
Okay, so for someone much slower than the rest of you... If my source does not invert, my preamp inverts and my amp does not invert my sysytem should be in absolute phase right? This way, my sytem would be set up properly for recordings that have been recorded in absolute polarity (although many recordings are not.) If I then wanted to confirm that my end result is absolute polarity would an absolute polarity checker accomplish that? (My amp is french and they are terrible about responding to inquiries) so, I am not 100% sure that it does not invert phase and would like to be able to confirm my end result with such a tool if that is what the tool is intended for. |
No. For the connections you describe, your system phase would be inverted. Invert: to reverse in position or relationship. What comes out is inverted, or reversed, in relation to what went in. Non-invert: to keep the position or relationship the same. What comes out is not inverted, or reversed, in relation to what went in. If only one of your components in the chain inverts phase, the end result is an inverted phase. If you have two inverting components in the chain, the output of the first is inverted. This inverted signal then goes into the next component, which inverts the signal, resulting in an output that is now in-phase, or very close to it, from the original signal. Lay a coin on the table, either side up. Now flip it over, or invert it, and the other side is up. Now flip it one more time. Aren't you back to the side you started with? One thing may be confusing you about this. The components in your system do not have a clue as to what the absolute phase is, nor do they care. Forget about phasing in recordings because this is a whole other can of worms. I've heard it said that phase is, more often than not, inverted many times through the recording process. So stick to what you can control in your system. |
Adampeter -- Re absolute polarity checkers, looking at their website I suspect that the Smart Devices units that were suggested as possibilities in your other thread are no longer available. In any event, they may very well not be worth the expense, considering especially that you would only be using them once, at least until you were to replace a system component. I suggest playing a few high quality audiophile-oriented recordings that were made using just 2 or 3 mics (that will probably be indicated in the album notes), and that contain a lot of percussive sounds. Then re-listen with your speaker connections reversed. See if you hear a difference in the sharpness, crispness, and realism of the leading edge (the very beginning) of the percussive notes. If you do, use the connection polarity that sounds best. If you don't hear a difference, assume the power amp is non-inverting, and connect plus to minus so that the inversion in your preamp is corrected for. On another note (no pun intended :)), re the statement that 50% of recordings are out of phase, I would go further, and put it a little differently. I would say that on 90+ percent of recordings, the whole concept of absolute phase or polarity is meaningless. The great majority of pop recordings, and the majority of classical recordings as well, are processed through complex multi-track consoles where they are subjected to a bewildering array of effects and mixing. Not to mention that the original takes were probably done with a virtual forest of microphones (particularly in the case of typical poorly engineered recordings of symphony orchestras). The end result, when it comes to absolute phase or polarity, is inevitably a random hodge-podge of different sounds with different phases. So even if you had a preamp that provided on-the-fly polarity control, if one setting sounded better than the other on a particular recording it would more likely be due to random synergy than to your system preserving the "polarity" of the recording. Getting the polarity of your system correct is relevant primarily to the unfortunately very small percentage of recordings that are well engineered, using purist techniques. But then again, those are the recordings that we Audiogon'ers tend to have particular interest in. Enjoy! -- Al |
Why argue the point? Just do what the manual says. What's so difficult about that? Because all the manual can tell you is if that particular component inverts. But what counts is that the system as a whole should not invert, which as has been explained means that the total number of inverting components and inverted connections should be an even number (0 or 2 or 4). As to "why argue the point," that was exactly what I was getting at in one of my earlier posts. Just get the overall system polarity correct (i.e., non-inverting), and then you don't have to worry about whether or not it makes a difference. Regards, -- Al |
Anyone interested in facts? There are some interesting points(re: Absolute Polarity) 1/3 down on this page (http://www.stereophile.com/asweseeit/988awsi/index1.html) The book mentioned: (http://product.half.ebay.com/_W0QQtgZinfoQQprZ394637) is no longer cheap by any stretch of the imagination(I wonder why?). Some observations on the book, the "Effect" and their affect on the audio industry: (http://www.positive-feedback.com/Issue31/wood.htm) The Stereophile test CD(STPH 002-2) and 'Chesky Jazz Sampler and Audiophile Test Compact Disc Vol 1'(JD37) both have tests that will tell you if you can discern one polarity from another(obviously- some can't). It should also be mentioned that many recordings are produced out of phase, when being recorded: many engineers don't pay any attention to the relative phase of mics and instrument inputs(so there will be some in and some out of phase on the same recording), and there are many pieces of audio gear that invert phase(and don't mention it in the manual), and if the drivers in your speaker system aren't time-aligned/phase-coherent, even if you CAN hear the difference: You won't! Quite a crap shoot out there! More? (http://www.avguide.com/forums/how-listen-all-laser-read-media-correctly) |
Adampeter, Did you reverse the polarity at the speakers, or amp yet? Is so, did you hear any difference? ============ I played around a little yesterday listening to different CDs on my system. My Sonic Frontiers Line One preamp has a polarity phase invert feature which can be switched with the remote control. As others have posted with some there was no real discernable difference in sound from my speakers. But there was with others. Did I go through all my library of CDs? No.... Just a selection of a few. Standouts where a definite difference could be heard? Etta James, "Love Songs". Track #1, "At Last". Change? Etta's Voice. Inverted her voice was thin. Correct polarity her voice was full, a more moving presentation. Chris Rea, "Auberge". Track #11, "The Mention Of Your Name". Again the voice of the singer stood out. Buddy Holly, "From The Original Master Tapes". Track #20, "True Love Ways. Difference? Not only Holly's voice, the saxophone as well. Definitely the saxophone.... FourPlay, "Between the Sheets". Track #1, "Chant? Difference? The bass drum. |
Rodman -- Good references; thanks! Jea -- Thanks for posting those results. The thing I wonder, though, about preamps that have polarity reversal capability, is if there may be an additional significant variable present. When you reverse polarity, you are not only reversing polarity but you are changing the circuit configuration in the preamp, either adding or removing or selecting a different active stage somewhere in the signal path. So I'd be a bit more cautious drawing conclusions from that kind of test than from a test where the polarity of the speaker connections is interchanged, given that the polarity effects being listened for are alleged by many to be subtle at most. Regards, -- Al |
Al, remember that when you switch speaker cables you are also affecting wire directionality, or so I've read. In fact, I remember Doug Blackburn writing an essay on polarity suggesting that the primary audible change you hear (if you hear ANYTHING) is the effect of wire directionality rather than polarity. IME, there IS a more pronounced effect from switching speaker wires rather than changing polarity via the preamp's remote. Anyone for listening to some music? Dave |
Rodman, your research and references were very interesting. In addition to covering many of the aspects of absolute polarity, they really hit home on the need for time and phase accurate speakers to have any chance of hearing polarity differences. They also made it clear that polarity is not just a leading edge effect, but can be heard in mid frequency continuous asymetrical waveforms. I did not realize that previously. When you combine the phase inversions in mics, mixers and recording equipment, and the potential circuitry differences in a preamps polarity switches, you have a lot of variables even if you get the absolute polarity of your system correct. Still, I agree that is what you should do. Since I do have time/phase speakers and a polarity switch on the pre, I think I'll do some listening similar to Jea and report back. |
Jea48- I did experiment today. However, I was frustrated because I wasn't certain which of my CD's were recorded in absolute phase. My plan was to listen to a cd that was recorded in absolute phase and switch back and fourth; picking the set up that sounded the best. However, without being certain about the recording I didn't see any point. I sent an email to Pierre at Mapleshade and asked him which of his cd's that I own were recorded in absolute phase. I plan on figuring this thing out! |
Rodman thanks for the links. I also have the 'Chesky Jazz Sampler and Audiophile Test Compact Disc Vol 1'(JD37). Great test CD for testing phase, the imaging test is very good as well, when the imaging test goes off stage far left or right, my imaging goes right to the side walls trying to bust it down. I have used this test on a few other systems and when the imaging test goes off stage far left or right, the other systems almost go back to center or in that direction, don't know what up with that. I just happy mine does what it should. |
Adampeter- Pick up one of the test CDs I mentioned: (http://www.amazon.com/Stereophile-Test-CD-Vol-1/dp/B0000049XN/ref=sr_1_1?ie=UTF8&s=music&qid=1231724213&sr=8-1) (http://www.amazon.com/Chesky-Records-Sampler-Audiophile-Compact/dp/B000003GF3/ref=sr_1_1?ie=UTF8&s=music&qid=1231724265&sr=1-1) They both have tests that will remove any doubt as to proper phasing on the recording. |
Al, remember that when you switch speaker cables you are also affecting wire directionality, or so I've read. In fact, I remember Doug Blackburn writing an essay on polarity suggesting that the primary audible change you hear (if you hear ANYTHING) is the effect of wire directionality rather than polarity. IME, there IS a more pronounced effect from switching speaker wires rather than changing polarity via the preamp's remote. Anyone for listening to some music? Dave Hmm, some interesting food for thought. I'll say first that I am not in a position to take a position on cable directionality, but I have the following questions and comments: 1)Which end did you switch? Interchanging + and - at the speakers would not change cable directionality -- the electron flow would be in the same direction through each wire, and in the reverse direction only within the speaker. Interchanging at the amplifier end would reverse the direction of electron flow through each leg of the cable. 2)Was your experience with speaker cables that were basically unshielded wire, or did they incorporate passive networks (a la MIT) that might have been direction sensitive, or did they perhaps have shields (whose physical configuration and grounding might contribute to directionality). 3)In this reference, http://www.6moons.com/industryfeatures/polarity/polarity.html, it is stated that reversing polarity at the amp end can reduce overall distortion, by causing amplifier-generated harmonic distortion to be out of phase with speaker-generated harmonic distortion. I haven't thought that through sufficiently to conclude whether or not it makes any sense, and offhand it is very conceivable to me that it does not, but if so perhaps that was a factor in your findings. Regards, -- Al |
Al, I switched the cables at the speaker end. The cables I was using at the time were shielded. Doug Blackburn's contention was that the cable-switching affected signal flow directionality of wire and other devices (capacitors, etc.) inside the speakers (soundstage.com/maxdb/maxdb101999.htm) if i understand him correctly. Further, he questions the audibility of polarity-switching per se. Needless to say, self-proclaimed polarity guru Clark Johnsen ("The Wood Effect") opposes Blackburn's views, to put it mildly. I'm honestly not sure who's right. I only know what I think I hear, and fortunately it's repeatable. Thanks for the 6moons article. Very interesting. Dave |
