Gad, half of the CDs out there have reversed phase and a good 1/3 of the vinyl have reversed phase....For those without phase switches the Reference Recordings final movement of Symphony Fantastique is duplicated on an extra disc which is out of phase with the same cut on the remaining disc........A friend of mine is into classical recordings and says that virtually all the old Mercury's and RCAs that are poorly reviewed are reversed phase..... |
Rich, I'm sure you realize that this a different scenario and question. I can't see what "fixing" the master in this regard after mixdown could entail except by selectively using info from only one of the channels as necessary to cross-feed into a new panned-'stereo' mix... |
I found this in the January 2002 Stereophile analog corner where Mike Fremer tells that he purchased a mint second pressing-the desireable one-of Jimi Hendrix's Electric Ladyland (Reprise RS 6307). And I quote: this pressing (all-mustard-colored Reprise label without the "W7" logo) is the one to have: engineer Eddie Kramer told me that when he and Hendrix mixed the album, they included all kinds of out-of-phase material designed to create a surround-sound effect from two speakers-especially in the whirring sound effects at the beginning and end of this two-LP set. When the mastering enginners at Reprise in L.A. got the tape and put it up on an oscilloscope, they were horrified to see all of the out-of-phase information and, without asking anyone, "fixed" it. When Hendrix and Kramer heard the first pressing (orange-mustard "W7/Reprise" label), they went nuts and demanded it to be restored to their original intent for the second pressing. Un-quote. Rich |
Last nite had a listen to a couple of LPs and this time, I took the extra step of reversing polarity using the spk terminals. I have to say that reversing polarity with LPs IS audible. If its out of phase, the music appears to be disoriented, veiled, or somewhat odd.
I might try it out with some CDs later to see what happens. |
Back in the days of matrix quadraphonic, I experimented quite a bit with phase issues. If your preamp has this capability, here are some interesting things you might try.
1. Run one channel inverted all the time, and reverse the speaker wires to compensate. Since most of the music signal is common mode (same in both channels) your power amp will work better because the draw from the plus and the minus power supplies is evened out. (Dynaco specd their old Stereo120 amplifier at 60 watts per channel (with channels driven out of phase). That last part, in parentheses, was in very small print.
2. If your amp can handle the low impedance (and most will because of item 1 above) bridge the power amp with another speaker. Presto! Instant center channel with perfect phase relationship to Left and Right, differential configuration for lowered distortion, zero cost for amplification, and having twice the power as appropriate for the center (common mode) signal.
3. You can achieve perfect Left/Right channel balance (very important for matrix multichannel) by puting the phase back to normal, playing a Monaural signal like FM interchannel noise, and listening for a null (silence) from the bridged center speaker (or earphones). In my case, in addition to adjusting the Balance control, I needed to touch up the Tone controls to get a perfect null.
There is lots more fun to be had fooling around with phase. Enjoy. |
Zaikesman, yes, one shd always get the polarity right. I too have a polarity button on my DAC, but never used it, except by accident. Which DAC do you use? |
Cmk, I agree with you on that statement (obviously many folks such as Bob may take some exception), even if it seems to somewhat contradict your previous post. What it really means is that what you're hearing would likely seem largely the same to you even if your phonostage did not invert polarity. But I agree with Bob's implication that if you're not going to futz around with polarity as standard operating procedure (as I do not), then it's still probably best to just make sure your system is polarity-correct before putting the issue out of your mind. My DAC has long had a polarity-invert button, but I never end up using it. My latest preamp is the first one I've had with remote polarity control...maybe I'll start trying to experiment with this aspect more in the future and see if I get anything out of it worth the bother, at least with certain types of music and recordings. |
Zaikesman, I dunno about you, but not everyone can hear the difference when the phase of a recording is reversed, at least I couldn't. There was a test CD on Chesky, can't remember which one, that had David Chesky doing some recording in and out of phase. Frankly, I hardly heard a difference. Of course YMMV. |
Yanx the phase phenomenon is not just exclusive to phono - compacted disc exhibits the same issues. I've found that the phase invert button on my full function preamp sometimes improves certain cuts on an (LP or CD) by enhancing one or more of the following:
Dynamics. Bass extension & control. HF articulation. HF harshness. Vocal naturalness. Weak-ish 'washed out' sounding cuts.
That phase buton works almost like a tone control sometimes.
Note that not *all* cuts on the same LP or CD will benefit from phase inversion; some do while others don't. As Zaiks says, it's a simple matter of experimentation. Those cuts that do not benefit from inverted phase will typically, but not always, run much better when non-inveted. The 'correct' phase is typically easily determined by a brief listening sample & a few button-presses to compare subjectively. |
Cmk - If your contention that 1/2 of LP's are pressed with 'reversed phase' were true, and if reversing your system's polarity 'fixed' something like 'weaker bass' supposedly caused by this, then your phono with the inverted polarity woud cause the other 1/2 of LP's - the ones pressed 'in phase' - to display the same alleged symptoms. If you're not prepared to experiment finding the 'best' polarity for each recording, then by your reckoning at least half will be played back 'wrong', whether you arrange your system to be always polarity-correct or always polarity-inverting. Yet, you say you "haven't had any problems." Think about the implications... |
The 5LP Elvid Presley Box set of his Las vegas live concerts is an obvious LP I know of.
It sounds like when he is singing like he is breathing in when he should be breathing out. very undynamic and unmusical.
Find it hard to believe that they missed this when they mastered the LP.
cheers shane |
Not sure about that. I do know that about half of LPs pressed at the time, maybe still, are reversed phase. Most of the time, it doesn't matter to the sound, but on certain LPs, you will notice weaker bass. Reversing polarity, either at the cart or the spk terminals, should solve the problem. I haven't experimented with this, but my phono reverses polarity anyhow and I haven't had any problems.
If you do try, let us know. |
Cmk - That's amazing...Do you have any clues as to why Sheffield would press this record with what they considered to be 'incorrect' polarity if they were clearly aware of the issue? |
Dave Grusin - Discovered Again on Sheffield Lab.
There's a note in the centre of the folder that's marked to Audiophiles to reverse polarity for best results. |
Although it's still possible that a record such as your example would sound better one way than the other as far as polarity goes, a multi-tracked studio pop recording like that does not really possess a "correct" absolute polarity, because all the individual tracks which have been mic'ed, EQ'ed, and mixed separately to arrive at the final stereo master will neither possess integrity of relative phase characteristics, nor will they necessarily all have their individual absolute polarities preserved throughout the electronics chain. Also, the electric and synthetic instruments used will display somewhat arbitrary phase characteristics. So no one absolute polarity setting on playback will be all right or all wrong - if you hear a difference, it will likely be more a matter of preference and chance than of 'phase-reversal' during disk mastering.
The concept mostly applies best in theory to live performance acoustic musics recorded at natural mic distances with naturally equal, true-stereo minimal mic configurations, in actual performance spaces rather than isolation booths, where all the instruments and voices can arrive together at the mic's with their natural phase relationhships mostly intact, and cannot have those interrelationships altered through multitrack mixing and EQ. Then a 'correct' absolute phase could be said to exist, but even then probably only an audiophile-oriented recording label could be counted upon to preserve the overall phase integrity by not heavily EQ'ing the master, not rerecording or overdubbing spot-mic'ed touch-ups, and taking care to preserve absolute polarity during mastering. If that care wasn't taken with a particular recording otherwise fitting this description, then reversing polarity on playback might make an unqualified improvement, or at least in theory (there's debate over how sensitive the ear actually is to absolute polarity even when the recording justifies the term, and it's hard to entirely rule out spurious factors for listeners' stated preferences in this area).
I remember once reading a reveiw on one of the online webzines where the writer insisted that at a stereo show he had recently attended, most of the displayers had their sound screwed up because they 'inverted' polarity, and that he went from booth to booth informing the exhibitors of their mistake within seconds of having walked into a room and listened to the music. He said all the music that sounded 'washed-out' or the like was certainly suffering from 'incorrect' absolute polarity, and that he couldn't believe that others didn't instantly hear this like he could, no matter what type of recording was playing. He also claimed that every exhibitor who followed his advice got much better sound period, regardless of what other disks they put on. Bullshit! Bottom line: just listen the way that sounds best - if you can tell a difference at all - but take the audiophile proclamations about the sacredness of 'absolute polarity' with a large grain of salt. There are reasons why even the best recordings - and stereo systems - don't fool us into thinking we're hearing the real thing, and the inability to perfectly preserve the natural time relationships you hear live is one of them. IMO. |
http://www.silentrunningaudio.com/contact_sra.htm
If you click "Absolute Phase Chart," they'll give you a list of inverted phase companies. However, they now require a name and e-mail for the download. |
