[Tympani]

James, I am eagerly awaiting my BDA-2 and BDP-2, due in 2 weeks. As one who is blessed (plagued?) by the ability to consistently hear a "correct" absolute phase setting for most recordings, I have found this switching to best be performed in the digital domain (short of switching speaker leads, a real pain to say the least). Any possibility of firmware updates that would allow this on the DAC?

Dan

[James Tanner]

James, I am eagerly awaiting my BDA-2 and BDP-2, due in 2 weeks. As one who is blessed (plagued?) by the ability to consistently hear a "correct" absolute phase setting for most recordings, I have found this switching to best be performed in the digital domain (short of switching speaker leads, a real pain to say the least). Any possibility of firmware updates that would allow this on the DAC?

Dan

I will ask - it would have to be a RF code I think. 

James

[Tympani]

Any more thoughts on Absolute Phase switching?

[kernelbob]

Tympani,

I absolutely agree with you on the audibility of absolute phase.  I've also found that it's best performed in the DAC instead of the preamp.  Every time I've tried it with the preamp, there's always been a "preferred" setting in the preamp where the alternate setting sounded more colored, not quite as clean, fast, etc.  My guess is that there's an extra contact or circuitry one way versus the other.  When performed in the DAC, via software, the difference is definitely audible, but both settings are equally clean.

The difference I hear, at what I consider correct for any given recording is: 1) more extended bass including what I think of a "subterranean" bass; 2) a more solid center image;  3) a deeper soundstage;  4) a smoother more musical upper midrange to lower treble.

For the same recording at what I consider the incorrect setting:  1) less bass impact and definition where the bass sounds more rounded; 2)  the center image is stretched between the speakers almost like a dumbell with two "lumps" of sound (one on to the left and right of the center);  3)  the sound is more edgy, irritating, and artificial;  4) this last one is the most odd, there's almost a nasal quality in that upper midrange area that makes me feel like my sinuses are slightly congested.

I would not have a system where I couldn't switch absolute phase from the remote control.  It is so simple to choose the correct setting for the system at the start of any recording.  I like to use Pandora for casual listening and there doesn't seem to be any consistency regarding absolute phase.  With experience, you can tell if on first hearing a track whether the current absolute phase setting of the system is correct or incorrect relative to the current track.  Of course the difference is equally obvious on higher quality inputs.  Sort of like having perfect pitch.  Would that be an absolute sense of absolute phase?

[JerryLove]

Does "absolute phase" mean something I'm not aware of: because my Louis Armstrong recording is almost a century out of phase.

Now "relative phase" on the other hand...

[Elizabeth]

For me, I can hear the 'phase' as either be the image in front (correct) phase or 'behind' (inverted phase) with dipole speakers.
I first noted this with Infinity RSIIa  I used to own, and again with my Magnepan 3.6

[Speedskater]

It's "polarity" with a yes or no state.
"phase" is a comparison between two signals or frequencies with a value of 0 to 360 degrees.

[James Tanner]

The problem these days is that most recordings are multi-mic recordings with totally different components between the instruments or voice being recorded. Then they are manipulated in the mix down and mastering phase (no pun intended) so any specific instrument or voice may have absolute phase throughout the recording process while another instrument will have inverted phase within the same recording.

So unless the engineer sets out to make sure his multi mix recording has each and every instrument in absolute phase it is a crap shoot.

James

[kernelbob]

Relative phase is whether the left channel is in phase with the right.  If the system is in correct relative phase, a mono bass signal will move the woofers in the same direction.  If you've got that wrong, a mono signal will not be localized between the speakers, but will seem to come from all directions.  You'll know when you've got that wrong.  That's a onetime fix.  If you have a recording that's out of relative phase, the person that did the last quality control check had a very bad day.

Absolute phase refers to how the original live performance compares regarding phase to how it's being reproduced on your system.  For example, assume that a given wave front in the live performance consists of compression, rarefaction, compression, etc..  If your system is set for proper absolute phase for a recording of that performance, it will regenerate that "compression, rarefaction, compression, ..." wave series.  If your system is set to the wrong absolute phase setting, it will generate a "rarefaction, compression, rarefaction, ..." wave series.

Unfortunately, as the sound is digested through all the steps of the recording and reproduction process, the end product that's input to your audio system may be either correct or inverted in absolute phase relative to the live performance.

The human ear does not respond symmetrically to compression versus rarefaction sound energy.  It's actually slightly less sensitive to compression than rarefaction.  Include the subject of just how the brain converts the nerve signals from those alternating pressure waves into our perception of the timbre of music, localizing sonic images in space, etc., and I have to refer you to Arthur C. Clarke's sentiment-- "any sufficiently advanced technology is indistinguishable from magic".  Nonetheless, when you toggle the absolute phase setting of your system, changes in various qualities of the reproduction are audible.

Having the capability to switch absolute phase on your remote makes the correction of this issue trivial-- just switch between the "invert/normal" setting and let your ears/brain be the judge.  It should just take a couple of seconds.

Regarding the question of whether this makes a difference in multimiked recordings, in my experience the difference is still clearly audible.  Even with multimiked recordings, a decent engineer or producer should at least have all the inputs in phase.  In my experience, multimiked recordings are definitely inferior to those using a very small number of microphones (e.g. the Decca "tree").  The most gross offender that I've heard is DG' awful "4D" recording technique where they used lots of microphones to spotlight various instruments and then use mixing boards as a musical Cuisinart to mix the signals together.  Even on those abominations, switching absolute phase is clearly audible, though the correct absolute phase setting won't turn a DG 4D recording into a classic Decca one.

[kernelbob]

James, please note, I didn't mean to say that the engineer has to have set up all the inputs from the recording to be correct absolute phase, just in correct relative phase-- i.e. that all the inputs are in phase with each other, whether or not the signal is in the same absolute phase with the live performance.  The issue of the absolute phase setting can wait until the sound comes out of your audio system, when you can toggle "normal/invert".

[JerryLove]

Relative phase is whether the left channel is in phase with the right.  If the system is in correct relative phase, a mono bass signal will move the woofers in the same direction.  If you've got that wrong, a mono signal will not be localized between the speakers, but will seem to come from all directions.  You'll know when you've got that wrong.  That's a onetime fix.  If you have a recording that's out of relative phase, the person that did the last quality control check had a very bad day.

I doubt it. You'll always be a little out-of-phase. Firstly, there's the simple propagation delay (measured in nano-seconds), and differences in the air between you and each of the speakers (again nano-seconds), and differences in distance (this can move into microseconds), and differences in *average* arrival time due to early reflection.

Further: relative phase has been, for decades, used to describe phase differences between frequencies. See also "phase delay" and "phase shift" in describing (in particular) cross-overs.

Absolute phase refers to how the original live performance compares regarding phase to how it's being reproduced on your system.  For example, assume that a given wave front in the live performance consists of compression, rarefaction, compression, etc..  If your system is set for proper absolute phase for a recording of that performance, it will regenerate that "compression, rarefaction, compression, ..." wave series.  If your system is set to the wrong absolute phase setting, it will generate a "rarefaction, compression, rarefaction, ..." wave series.

I'm not sure this is accurate either.

Imagine a sound of two frequencies. One is 1khz and the other is 100hz. Imainge that there's a phase delay introduced by the crossover of 1ms. The 1khz signal will be described as a 180-degree phase-delay, and the 100hz signal will be described as a 18-degree phase-delay putting them out-of-phase with one another.

Except that the wavefront would still be identical. It would be an accurate sound with an apparent phase-issue.

Unfortunately, as the sound is digested through all the steps of the recording and reproduction process, the end product that's input to your audio system may be either correct or inverted in absolute phase relative to the live performance.

Now you are back to using "absolute phase" the way I did.

I'd be willing to bet that, if you reversed the polarity on all of your speakers together, you couldn't tell the difference. You can if you reverse only some, but not if you reverse all.

[kernelbob]

Jerry,  regarding your first section of comments regarding relative phase.  Play any mono recording.  reverse the phase of one of your speakers (reversing the +/- connections from the amp).  Isn't that difference obvious?  This difference has nothing to do with phase shift or phase delay in crossovers, etc.  This is just the gross setting of your system's left/right relative phase, nothing more.

Regarding your second point, let's keep it simple and compare what happens in the bass.  The sound of a bass drum sounds very different when you switch your system's absolute phase.  Can you try it on your system?

The last quote you reference from my post addresses the fact that by the time the recording gets to your speakers, it is a tossup as to whether absolute phase is normal or inverted .  My only point there is that there are so many steps in the process chain where the absolute phase may be inverted (or re-inverted back to being correct), that you can't know if the absolute phase of the reproduced event in your listening room is "normal" or "inverted".  That's why you need an absolute phase toggle on your remote, so you can test it both ways and choose the one that your brain decides is correct.  It doesn't matter how many times absolute phase was reversed in the recording/reproduction chain, all you have to do is to choose the polarity from your listening position.  As for audibility in my two channel system, the difference is definitely audible which I've been able to demonstrate to even casual, non-audiophile listeners.

[Speedskater]

Yet more on Polarity and Phase:

"Graphic-Based Discussion That Clarifies The Differences In Polarity And Phase"
Feb. 05, 2013, by Chuck McGregor

http://www.prosoundweb.com/article/a_graphic_based_discussion_that_clarifies_the_differences_in_polarity_and_p/study_hall

[Tympani]

I didn't really mean to start a long discussion, except to say that some of us (thanks Kernelbob) hear the effect, in no uncertain terms. The "correct" selection for any given recording, is consistently reproducible, and provides a much more rewarding listening experience. There's been much (often contentious) debate on audio sites about the audibility of correct polarity. No need to revisit all that.

I have found, in my brief exposure to these 2 fine components (BDA-2 and BDP-2), that the correct polarity, especially on hi-rez material, is even more clearly apparent, which speaks to the transparency of these components. So far I've been accomplishing this with my speaker leads, a real PITA. In true audiophilia nervosa fashion, I have placed a "minus" or "plus" before each album title to identify the preferred setting before playback.

A remote (or manual) switch on the DAC would be "da bomb"