Inverted Phase on CD´s - why?

[Klaus]

Hi Digi listeners,

I want to understand more about one effect: phase inverted records.

Before I got a DAC with inverting possibility in ´96 I found the sound of many CD´s "strange". Somehow pulled wide, missing depth of soundstage, dynamically limited and a bit of aggressive. With having this INV-button I immediately found the explanation, the CD´s are just inverted. Checking which CD´s are inverted (from view of European devices) I found astonished, that all US-CD´s and most of the Japan-CD´s are inverted, all the others are not.

I communicated it over the years with many guys who found exactly the same effect. Lucky to have this INV-button, but what is the reason???? The only explanation could be that in US an other standard for CD´s phase is valid. Who could please explain the truth about! What are your experiences?

Regards

Klaus

[Da5id4Vz]

So your saying that it’s the absolute phase, both channels that are inverted, or is it that one channel is inverted?

It could be that for years most US CD's were mastered on Sony PCM 1630 Equipment with just a smattering of Digidesign and Sonic Solutions stuff out there.

In Europe I think the old standard was the Harmonia Mundi platform.

It wouldn’t strike me as too unlikely that originally one or two of the workstation based buys could have followed the lead of someone else and gotten absolute phase topsy-tervy. I would be supposed if this situation would have existed too long though.

Can you find any time correlation of when the recordings were made to when the effect takes place? Is it the case with today’s recordings too?

[SimontY]

Hi Klaus,

I wish I had a phase inverter switch to play with :-(

Apparently a lot of equipment reverses absolute polarity too, not just the recording. So, it is feasible you have have it the other way round, and are switching it one way and not the other! Irrelevant maybe, but interesting.

Apparently, some tracks (I don't mean cd tracks) can be recorded in one phase and some another, so it will bever be fully 'right' on some recordings. According to Robert Harley (iirc) in 'The Ultimate Guide to High End Audio' changing absolute phase only makes a small difference to SQ but is most significant in accuracy of transients like drum hits - iirc - I will look later when I'm at home

I reckon it is lack of universal standards and recording engineers generally not giving a to55, well maybe.

Anyone know how to easily add a phase-change function in say, a cd player, with a switch at the back maybe?

This is an interesting topic, could be one more reason not all my CDs sound so great...

Someone here must know a lot more about this than I do, please enlighten us!


-Simon

[SimontY]

Da5id4Vz,

I believe we are referring to both channels being inverted.


-Simon

[ashok]

I have come across some CD compilations from the Far East with the phase on one channel inverted. 80% of the tracks were OK.
As Klaus said the image seems to be pulled wide and it sounds very thin as the bass gets lost due to phase inversion in one channel. Those who don't know the effect can invert the connection on one speaker to see what it is like.

Both channels inverted together is very different. It does not sound as bad -- probably just a bit different from normal phase! Many people have their own opinions on the audibility of absolute phase inversion.

Cheers.

[Da5id4Vz]

Absolute phase can be quite easy to invert in the analogue domain. Transformers, op amps, and sometimes reversing tip and sleeve will all do the trick depending on application, taste, and sensibility.

Did you catch my above ponderings about the mastering euipment used?

[fmak]

[QUOTE]Originally posted by Da5id4Vz
[B]Absolute phase can be quite easy to invert in the analogue domain. Transformers, op amps, and sometimes reversing tip and sleeve will all do the trick depending on application, taste, and sensibility.

----------------------------------------------------
Many SACD recordings are phase inverted, and of course some CDs. Very easy to ell on jazz/big band in respect of the bass, and classical in terms of instrument placement and treble.

I posted a comaprison of 24/192 with DSD upsampling from CD with matched gain and made the point that DSD seemed to be closer to 24/192 when phase is reversed. This could have been due to the effects of filters and time delay in upsampling. The point was dismissed outright by some people who I don't believe have ears!!

[ashok]

Did you catch my above ponderings about the mastering euipment used?

I am not into pro audio gear and so cannot comment on the equipment. In the digital systems it is probably not so easy to goof up unless one is careless ( flick a switch !). But in analog it is possible easily as you pointed out.
Cheers.

[Da5id4Vz]

I think my thoughts about mastering equipment is that there was a predominant difference in equipment and manufactures being use to master CD's in the 80's and early 90's.

Japan and US, were mostly Sony.
Europe was (I think) mostly Harmonia Mundi.

It would not surprise me that in these early days of the art, that a manufacture such as (hypothetically) Sony, might have gotten the ab-phase issue a little bit wrong. And yes I also think it likely that may have taken a bit before the exact texture of the emperors clothing was noticed while everyone was grappling with this new medium. (Hypothetically of course)

[fedde]

Getting the absolute phase wrong is quite easy. Only swapping the leads of the microphones does it...
I've heard that in some records the instruments have different polarities, even in one track!

I have a Denon DA-500 with a polarity switch. IMHO absolute polarity is audible, though the difference is not extremely large. I'll try to get a wave/mp3 player with a polarity setting so I can compare quicker and easier.

Fedde