In-Phase Out-Phase Function


#1

(please relocate if this topic has been addressed elsewhere)

In exploring a new (2/2017) DS Sr., I’m going through a Stereophile test CD that has samples of in-phase and out-of-phase white noise. I clearly hear the difference: more focal presentation of the sound between the speakers when in-phase; and diffuse white noise to the sides of the speakers as well as in between when out-of-phase.

I thought perhaps changing the phase on the DAC would reverse the results of the test signals, e.g. bring the out-of-phase test track into phase, creating the focal, central sound. However, despite the change of the indicator on the control panel of the DAC, I could hear no alteration whether playing the in- or out-of-phase test track. Indeed, in my general listening over the past weeks, I’ve not been fully confident of any change in the in-phase vs. out-of-phase sound as regulated by the DAC.

Am I missing something? Is this feature functional in Torreys? I’m running Torreys with balanced outputs, I2S input from a DS MemoryPlayer, Spectral pre- and power amplifiers, MIT Reference balanced cabling and power regulation, and gigantic Thiel speakers. It is a very resolving system. The DAC and DSM have about 400 hours on them.


#2

I too am using balanced output and I2S input from a memory player (as well as a DVR via optical input and a universal player via coaxial input). . . and . . . I can hear the differences between “IN” and “OUT” when I change between them. . . .


#3

Test CD phase in/out test is not about absolute phase but relative phase which is pretty easy to detect.


#4
Nobo said

I thought perhaps changing the phase on the DAC would reverse the results of the test signals, e.g. bring the out-of-phase test track into phase, creating the focal, central sound.

The test signals in question either have both channels the same or ONE channel with a different polarity than the other. Pressing the "Phase" button swaps the polarity of both channels so now you still have two channels the same or one channel with a different polarity than the other.

[Edit: frode beat me :slight_smile: ]


#5

Interesting. I’m not sure I understand, but on the DAC does changing to out of phase invert the phase of both right and left channels (absolute), but on the test CD out of phase means inverting the phase of only one of the channels (relative) as if the pos and neg wires of one speaker were reversed?


#6

So the Phase button on the DAC doesn’t correct for a reversal of polarity for one channel along the chain from CD to speaker (or correct for a CD in which the channels are presented out of phase); rather it addresses the phenomenon that some recordings may not present the optimal phase for the mechanics of sound production at the level of the speakers?


#7

Yes you have it correct. One channel with a different polarity than the other (like the test CD) is quite easy to hear with material that otherwise would be centered in the sound field. As frode alluded to, reversing the polarity of both speakers (or using the polarity switch on the source, premp, etc.) is usually harder to hear for most people.


#8
lonson said

I too am using balanced output and I2S input from a memory player (as well as a DVR via optical input and a universal player via coaxial input). . . and . . . I can hear the differences between “IN” and “OUT” when I change between them. . . .


I have thought I can hear the difference on some recordings but not all; certainly not as striking as the relative phase inversion on the test CD.

Of course, my ears are out-of-phase by 37 degrees, so it’s hard to tell. wink

(just kidding)


#9

Absolute polarity is a complicated matter: most production chains have plenty of loopholes where the absolute polarity of a given element may be missing or wrong. After mixing and mastering it’s easy for some of the instruments/performers to be in different absolute polarity than others, or perhaps, in the best case, for one track on a CD to be in a different absolute polarity from another. Some labels are better about this than others, but in the end you should just pick the polarity setting that sounds the best to you for each track or forget about it altogether.


#10

Thanks Ted and everyone for your explanations!


#11

There still exist CD’s that claim to run such a test, but I believe it cannot test the whole chain (end to end transfer function).

You only know your starting point vs your output.


#12

Just for fun, if you’ve never heard of George S. Louis and his absolute polarity war visit http://absolutepolaritygeorge.com/ or http://audiogeorge.com/30-years-of-digital-and-the-92-solution/ (be prepared to be confused.)


#13

For better or worse, I’m very sensitive to polarity, not only on recordings, but in live settings. There are two halls in NM with such serious phase problems that there are only a couple of seats where I can enjoy the music. Apparently, many people–HP of Absolute Sound, for example–don’t seem to notice incorrect polarity.

On recordings, older DGG LP’s, and CD’s made from older tapes are very likely to require reverse polarity (that is, “out” on the Directstream and “P” on the Jr.). Stockfisch (another German company offering exceptional recordings) SACD’s all require reverse polarity for best sound. That’s one reason that I buy PS Audio products–you can reverse polarity even on SACD’s.

The standard, in my experience, is Phillips, which always has correct polarity. Most US recordings (including many DGG recordings made in the US, such as the Orpheus CD’s) have correct polarity.

A quick story. Two years ago I was in a room at the Rocky Mountain Audio Fest when a reviewer from a major magazine arrived. The hosts played Michelangeli’s Beethoven 1 concerto LP. The reviewer loved the sound. But the polarity was incorrect, so the piano sounded to me as if it was covered by a blanket.

Ted is correct–if in doubt, switch polarity to see if it sounds better. Signs to listen for: transients (piano, percussion) are not sharp; violins have an edge; plucked string bass notes don’t start with a clear pluck; and limited depth on recordings known for having a deep soundstage. Also, if there are phase problems in the room (due often to speaker placement issues) polarity is easier to hear.


#14

So, right after writing the above post, I checked out absolutepolaritygeorge.com cited a couple of posts back by Ted.

At the bottom of the first page is a list of disks and labels that have reverse polarity (George calls the “IN” polarity on the DirectStream “normal” polarity). Several entries caught my eye, including Miles’ “Kind pf Blue” and all Phillips recordings, listed as having reverse polarity.

So I checked. He is correct. On Kind of Blue, the first track, “So What” has an intro that starts with a repeated three note pluck on the bass and ends with a more complex short phrase on the same instrument. Played in normal polarity, that phrase has always seemed indistinct to me. In reverse polarity, the pitches are clear. And on several Phillips disks, the sound was much more lively in reverse.

So, my citing of Phillips as the standard for normal polarity is flat wrong. George lists Telarc as always normal, which is also my experience. My recommendation is to check the website if you want a list of recordings that can be used to determine if you can hear differences in polarity.