Inverted absolute phase vs inverted absolute phase

[AlainGr]

Peter,

I know that topic is not recent, that's why I am creatind this as a "new" topic.

I do have a remote control for my pream. Since it is quite an old preamp, it is wired... There is an absolute invered phase button that I can press "on the fly", but... Well, I don't find it easy to determine if a song is in inverted phase or not. For sure it would be meaningful if I was starting this with "I can hear a difference"... But I am not sure, so I should assume that I don't.

My question is: can you determine with a quick analysis if a song starts in absolute inverted phase or in its contrary ?

I'll start with that, before asking other questions...

Thanks.

Alain

[PeterSt]

Hey Alain - No.

I can't because of not being sensitive enough to it.
But I also wonder whether it is the way to go to have this different per album or even track.

What I do know - and can hear - is when Inverted Absolute Phase is active. So, this is general and will count for all I play.

My advice : just make the connections right so all is fed to the speakers in Normal Absolute Phase and then switch it in XXHighEnd if you like that better. But not per track or something - just in general.

Peter

[AlainGr]

Ha... Did not check my title correctly... Is it like "Spy vs Spy"

Alain

[PeterSt]

Coffee vs coffee + brandy vs brandy
What does it matter. As long as you have both.

[AlainGr]

Coffee vs coffee + brandy vs brandy
What does it matter. As long as you have both.

Of course And I can see that alcool and caffeine are 2 examples coming very easily to your mind

I did try once to detect if I could "see" how a waveform was beginning with Audacity, but no, it did not seem possible... My attempt was to determine if a wave would begin "negatively" or
not...

Alain

[juanpmar]

Hi Alain,

Maybe this test can help you:

http://www.audiocheck.net/audiotests_polaritycheck.php

Regards,
Juan

[AlainGr]

Hi Alain,

Maybe this test can help you:

http://www.audiocheck.net/audiotests_polaritycheck.php

Regards,
Juan

Hi Juan,

I have done this test, but it was not conclusive for me... There is (or was) a website where the author talks extensively about this (he seems to be sensitive to inverted phase), but there does not seem to be a way to determine easily if a file is in inverted mode or not...

It is said that to train our ears to find landmarks can help determine the qualities of a recording or what to compare, but for this I haven't found an easy way other than listening...

Yet I know that in the same recording, some components could have been in inverted phase while some others would not... It does not make much sense, does it...

Regards,

Alain

[juanpmar]

Alain, probably you have read this article but just in case:

"Phase issues take on a far different magnitude in a recording situation, and can quickly become complicated. In most recording sessions, we’re dealing with multiple instruments and multiple microphones. As sound waves of different frequencies reach different microphones at different times, the potential for one microphone’s diaphragm to receive a positive phase while another receives a negative is greatly increased, and the relationship between all of these different waves’ phases can be somewhat unpredictable. In fact, the more mics in play, the more inevitable some sort of phase issues become".

This is the complete article: http://www.uaudio.com/blog/understanding-audio-phase/

Juan

[AlainGr]

Ah... I see that the link you provide is related to polarity between 2 channels, like say the red wire is connected to the "+" and the black to the "-", and on the other speakers the red is on the "-" and the black on the "+". This is the relative phase between channels...

Using the same example, I was seeking for a way to differenciate  all speakers connected with red wire "+" and black "-", as opposed to inverting that (red with "-" and black with "+")...

Alain

[PeterSt]

In the end Juan sure talks about your (psychological !) problem.

[AlainGr]

Alain, probably you have read this article but just in case:

"Phase issues take on a far different magnitude in a recording situation, and can quickly become complicated. In most recording sessions, we’re dealing with multiple instruments and multiple microphones. As sound waves of different frequencies reach different microphones at different times, the potential for one microphone’s diaphragm to receive a positive phase while another receives a negative is greatly increased, and the relationship between all of these different waves’ phases can be somewhat unpredictable. In fact, the more mics in play, the more inevitable some sort of phase issues become".

This is the complete article: http://www.uaudio.com/blog/understanding-audio-phase/

Juan

Oops, we wrote at about the same time

Yes, this is what I al looking for Thanks Juan

Alain

[AlainGr]

PETER !

 

[juanpmar]

Well, I guess that at the end the best method to determine the correct phase are our ears. With the correct phase the bass is firmer and well located in one place, the voices are also well defined and located.

Could be also that the "out of phase" are ourselves, but that´s other story...

Juan

[AlainGr]

Well, I guess that at the end the best method to determine the correct phase are our ears. With the correct phase the bass is firmer and well located in one place, the voices are also well defined and located.

Could be also that the "out of phase" are ourselves, but that´s other story...

Juan

Well, from what I see and hear in the news, we for sure are out of phase with so many things

Alain

[PeterSt]

I did try once to detect if I could "see" how a waveform was beginning with Audacity, but no, it did not seem possible... My attempt was to determine if a wave would begin "negatively" or
not...

This software is in XXHighEnd too. It can't work ...
(so, disabled).

Personally I think the story about microphones and such is rubbish. As if we tend to twist the polarity of an XRL cable which isn't even possible.

The reason why it can't be detected in software (well, the other day I said that maybe today I can do it after all) is that it is an electrical phenomenon in order. So, any electrical signal needs a "sweep up" before it's normal amplitude is achieved. And the first "maximum peak" can be downwards (negative) or upwards (positive) at random. This is for the detection.

But if you look at loudspeaker driver diaphragms exactly the same happens. They need a sweep-up before the amplitude to achieve is there. The forward excursion can be max first, but the backwards can be the first just the same.
Got that ? Believe it ?

Now think of the microphone. Same story.

But this STILL is about detection only;
Practice works different, because the absolute proper phase (where a blow is to be perceived as a blow and not as a suck) will be about the average positive amplitude of the wave concerned and that positive amplitude being reached faster for its average (so excluding sweep up) attack, than that its decay goes.

What I am trying to say is that this can only be about averages and never about the first (high(er)) impulse which latter is random to either direction.

Peter