Swap one of the channels phase while not the other is instantly audible, it throws the whole music out. While just inverting the total phase of the system is very subtle and I’m not even sure if I hear a difference, if anything it is only in the bass kick but I’m not totally sure if it is a difference there
I got switches to invert the phase coming out of my DAC, it inverts the digital data going into the DAC and you can just switch it on the fly
I got switches to invert the phase coming out of my DAC, it inverts the digital data going into the DAC and you can just switch it on the fly
DaKi][er said:
I'm now convinced about the importance of the phase correctness (at least in the digital data going into DAC). The effect is similar to phase difference between channels, just more subtle. But not like many will suggest, IMO, it is crucial to have it right.
My concern is not with bass (as little difference in bass is not an issue to me and many of us), but with dynamic. As I remember it, the effect is like when I tweaked the feedback of Zen amplifier. First impression tends to favour minimal feedback. With minimal feedback the vocal seems more pure, but something is missing especially when the speaker was not easy for the Zen (P17WJ). With phase difference between channel, the vocal seems real, the image seems real, but dynamic is bad (not to mention weaker bass).
Due to first impression, at the beginning I decided to opt for less dynamic setup. But later after trying both setup for a long time, and when enjoyment is the only measure, I'm convinced that the one with better dynamic (ie. the one that gave me more pleasure) is the one with correct absolute phase.
While it is true that multi-mic recordings do a great deal of harm to the phase of the recorded signal, I look at it this way:
You're driving down the road.
You come upon a recent single-car accident.
The driver is badly hurt.
Do you:
A) Try to stabilize him and do everything in your power to help him get through, or
B) Kick him, scream at him, flail at him with a stick, rationalizing your actions by saying,"He's already hurt and might even die, so what's it matter?"
Remember the doctor's dictum: First, do no harm.
So the music has been twisted every which way but loose...so what?...that's no excuse for making matters worse. Your duty is to to handle the signal with kid gloves while it's in your care. Extend it every courtesy, ease its passage, treat it as gently as possible. Who knows, it might just treat you well in return.
And yes, a polarity/phase switch is a useful thing to have. Easier still if you're working with a balanced signal.
Grey
You're driving down the road.
You come upon a recent single-car accident.
The driver is badly hurt.
Do you:
A) Try to stabilize him and do everything in your power to help him get through, or
B) Kick him, scream at him, flail at him with a stick, rationalizing your actions by saying,"He's already hurt and might even die, so what's it matter?"
Remember the doctor's dictum: First, do no harm.
So the music has been twisted every which way but loose...so what?...that's no excuse for making matters worse. Your duty is to to handle the signal with kid gloves while it's in your care. Extend it every courtesy, ease its passage, treat it as gently as possible. Who knows, it might just treat you well in return.
And yes, a polarity/phase switch is a useful thing to have. Easier still if you're working with a balanced signal.
Grey
cs said:
Absolute phase is audible if the speakers are good enough, phase coherent, and good spectral decay charactersitsics. However, as mentioned in previous posts, not all recordings and processing take care to preserve the correct phase. So with a good recording, absolute phase would make more significant difference.
GRollins said:
There's no need to flatter Self. He didn't do anything no "hard core measurements-are-everything guy" wouldn't do. Scientific truths are never more than conditional. That is, they are truths based on what we know. Then there's that other important tool, Occam's razor.
You either believe in measurements, or you don't. There's no in between. Otherwise you enter la-la-land of Stereophile, a magazine that proudly defines itself as subjective yet publish objective measurements! That's like a lawyer telling the jury, "My client didn't kill that man. But if the evidence shows that my client did in fact kill him, then it was involuntary." There's a perfectly good reason why this kind of defences aren't admissible.
That's dishonest. That's not how science, or the world, works. What you are saying, to paraphrase James Randi, is that scientists should go out and measure chimneys in order to see how it's possible for Santa to get down one. Before we start measuring chimneys, lets FIRST find out if there is a Santa.
Unless you can glue your head to a single position, phase will always differ or varying (from the listener's side).
Try to find the CD (+-) by Ryuji Ikeda (and psycho/electroacoustic musician)... The CD is a bit dull in that a lot of it sounds like test tones, but move your head around and the position and shape of the sound changes. Great stuff. He also made Headphonics.
As long as you are getting even and proper polarity out of your speakers from the same distance, you have done the best that is possible.
Try to find the CD (+-) by Ryuji Ikeda (and psycho/electroacoustic musician)... The CD is a bit dull in that a lot of it sounds like test tones, but move your head around and the position and shape of the sound changes. Great stuff. He also made Headphonics.
As long as you are getting even and proper polarity out of your speakers from the same distance, you have done the best that is possible.
" I guess I'm the "hard core measurements-are-everything guy." I have a hard time imagine science without measurements. But what camp I belong to isn't important. It has no bearing on anything."
Why is it that some of the best measuring eqipment sounds horrible?
Because tin-eared meter readers designed and tested it.
No one knows how to absolutely correlate good sound with measurements.
Test equipment can sometimes tell me what is broken, that's about it.
A person with a technical backround and a good ear is more likely to come up with something good than either a person with a tecnical backround and no ear, or a person with a good ear and no technical backround.
Why is it that some of the best measuring eqipment sounds horrible?
Because tin-eared meter readers designed and tested it.
No one knows how to absolutely correlate good sound with measurements.
Test equipment can sometimes tell me what is broken, that's about it.
A person with a technical backround and a good ear is more likely to come up with something good than either a person with a tecnical backround and no ear, or a person with a good ear and no technical backround.
djk said:
I've actually sorted out some trends in relationship between what is measured and what is heard. Hopefully some criteria can be established so that designs made purely by engineering data can be good to a certain point.
Since the human ear can feel difference between pressure phase, so it's is acceptable to assume absolute phase is audible from a scientific point of view.
To describe the difference between the sound of the Sony PlayStation and the CD players I have heard, I compared the former to an old/mature virtuoso violinist and CD players to that of a young up and comer. Unfortunately, I'm not into classical music and cannot refer to violinists by name. But if you are, you probably know what I'm talking about.
These and many other things probably cannot be measured. But we can measure the tools that reproduce those things.
Music reproduction is a contradiction. Music is played by artists, usually romantics. But the sound systems are constructed by engineers, usually positivists. I have a love-hate relationship with engineers. I love them because they are great systems builders and because their innovations make my life easier. I hate them because their innovations, like computers, don't work well with humans, which makes my life miserable.
"Everyone knows nowadays that the ability to accept criticism and contradiction is a sign of high culture"--Nietzsche
These and many other things probably cannot be measured. But we can measure the tools that reproduce those things.
Music reproduction is a contradiction. Music is played by artists, usually romantics. But the sound systems are constructed by engineers, usually positivists. I have a love-hate relationship with engineers. I love them because they are great systems builders and because their innovations make my life easier. I hate them because their innovations, like computers, don't work well with humans, which makes my life miserable.
"Everyone knows nowadays that the ability to accept criticism and contradiction is a sign of high culture"--Nietzsche
Distances - the sounds sources to the microphones and the loudspeakers to the ears - alter the phase relationship between the components of the initial sound source. Then, one can only expect that absolute phase is somewhat preserved at very low frequencies... where the signal waveform is affected by the mutiple room reflexions.
To test one's ability to detect absolute phase, at leat the distance of the emitting tranducer to the ear should be made very short, so the use of earphones is mandatory. Then one may detect a subtle change in the sound when the phase is suddently reversed. But, then, it is much doubtful that one may reliably emit a distinct preference.
It is easy to understand why the absolute phase must be preserved at each stage of the production time (mixing desks and all other record-related equipement). There is no real reason why it should be the same in a listening-only system at home. An advantage of the inverting configuration of amplifiers is a slightly lower distorsion.
To test one's ability to detect absolute phase, at leat the distance of the emitting tranducer to the ear should be made very short, so the use of earphones is mandatory. Then one may detect a subtle change in the sound when the phase is suddently reversed. But, then, it is much doubtful that one may reliably emit a distinct preference.
It is easy to understand why the absolute phase must be preserved at each stage of the production time (mixing desks and all other record-related equipement). There is no real reason why it should be the same in a listening-only system at home. An advantage of the inverting configuration of amplifiers is a slightly lower distorsion.
djk said:
Oh please - you are close to making the most opinionated posts on this entire forum (and that is a feat). Have you listened to all the best measuring equipment and know it's designers?
Should they? How does that make all measurements null and void? I am sorry if measuring only tells you when something is broken, you mush have rather basic equipment and knowledge to operate it. Still, you seem to be absolutely correlating good sound with what YOU hear. Did someone mention Occam's razor just a few posts up?
BTW yes, absolute phase is audible. Just not absolute phase as it is normally defined (which is a pretty wobbly definition to begin with, as someone has already pointed out in this thread). I have provided the equipment to investigate this for a masters thesis at the local university, and was priv to the preliminary results. It seems to me that the conclusions one can draw from the results are this:
If we had linear loudspeakers (or at the very least without second order phenomena), DC coupled amplifiers that preferably never clip, or at least clip EXACTLY the same, and have perfectly stiff power supplies, and of course are devoid of at least second order phenomena as the loudspeakers, we'd likely have a VERY hard time hearing any differences in absolute phase, and what difference we would hear, would be because of the same phenomena within the ear (we'd need to play it pretty loud, though). Anyone using the impact of bass drums as a gauge for the audibility of absolute phase shopuld have picked up those clues. If it was up to the recording or the 'air' between the speaker and the ear, then the clues would be more readily seen in the midband, where the ear is more sensitive.
Part of the experiment done in order to investigate absolute phase involved invertinga DAC digital stream and the output of the DAc using an inverting amp (the DAC is actually completely differential and is the part I speciffically provided for them). It was found that the audibility of detecting the inversion of the DAC stream was statistically negligible, while the detection of the inversion by amplifier was statistically sigtnifficant. The interesting part is that detection accuracy increased rapidly with rising volume, and material containing asymetrical peaks (headphones were used for this). In BOTH cases it fell down to random figures when soupling was DC or the coupling capacitors were increased far beyond what is normally thought as acceptible (like by an order of magnitude). The most interesting part of the test has shown that using a DC bias current to the output of the amp changed detectability considerably - both in the positive and negative sense, depending on the level. I think this clearly demonstrates that 'absolute phase' may well be a misnomer, and certainly should not be looked for in the source material.
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