Jump to content
IGNORED

Phase changes with jRiver Media Center and ASIO4ALL


Valvefan
 Share

Recommended Posts

I have a question for the engineer/tech people out there.

 

I was using jRiver MC13 with ASIO4ALL. The path was USB out to an Ayre QB9 then balanced out to a preamp then balanced out to a power amp. It sounded wrong until I reversed the red and black speaker cables and then the soundstage got wider and the high frequencies became less strident. I recently installed MC14 and began using WASAPI. The sound was wrong again until I returned the cables back to the normal red to red and black to black arrangement.

 

My question is; can software changes alter or invert the phase of the audio signal?

 

I'm looking forward to hearing from you

 

Thanks

 

Valvefan (Pete)

 

 

 

Link to comment
Share on other sites

1. Software and Drivers can change the absolute phase of the signal and I have had two cases in the last two year, where this happened.

 

2. J.Rivers MC13 with ASIO4ALL under XP was bit true and so phase correct, as MC14 with WASAPI under Vista and Win 7 also.

 

3. Even when MC13 with ASIO4ALL and MC14 with WASAPI are both bit true with correct absolute polarity, they sound different. MC14 sounds different to MC13, and WASAPI sounds different to ASIO4ALL. So I can imagine, that you have the could have the feeling that with MC13 and ASIO4ALL you have to invert the absolute polarity to have a good listening experience.

 

PS; Sometimes, with some units this has some similarities with the direction, with I plug the main plug into the wall outlet. So even if you exchange the direction of the mains plug, this does not change the absolute polarity of the signal, but can sometime tend to the situation, that you feel, that you should change the absolute polarity of your speakers in order to enjoy the music.

 

Juergen

 

Link to comment
Share on other sites

Absolute Phase = The part of the signal meant as plus, should be treated in your system as plus (amplitude above zero). When we speak about absolute phase this always applies to both channels, meaning that an inverted plus/min applies to both channels at the same time.

 

With "polarity" in this context, we refer to one of the channels having the plus and minus swapped. The sound from both channels is now out of phase (what is plus on one side will be minus at the other, and they cancel out eahother).

 

Notice that when abolute phase is changed, both channels remain in phase. Some people are sensitive to this and "can't listen" to an inverted absolute phase.

Many devices invert the alsolute phase, as an individual amplifying step (opamp) already can do. So, it usually takes explicit action to output the same absolute phase opposed to what was input. Many devices though, don't care much.

 

It is said that during the recording process the absolute phase of the diverse individually taken instruments/voices are wrongly mixed, and so whether a device inverts the phase doesn't matter anymore because all is a mess to begin with.

 

Btw, software can do this wrong but it is a kind of hard (because you'd have to change + values into - values). Software can be used also to easily invert the Absolute Phase, and to my own findings this is necessary, depending on a perceived accuracy of the music reproduction. It has been reported that different versions of XXHighEnd (which all should sound the same because I didn't explicitly change things) require inverted phase (which is a setting indeed) beyond a certain setting of something else (fyi Q1). Since virtually everyone perceives this the same (including me), indeed something will be going on in this area, independent from rooms etc. Piano music seems very sensitive to this and the notes seem to fall apart (less coherent) when the absolute phase is not according ... well ... what it "needs" ?

 

The above (I hope) clarification is merely because Juergen mentions "absolute phase / absolute polarity" and I am not sure whether he refers to the phenomenon as I do, and at least it looks like Juergen doesn't refer to what you are talking about, Pete. So, you are referring to "out of phase" (change the polarity of one of the channels is sufficient to get that), and software can do that theoretically wrong, but it is more hard than doing the absolute phase wrong, because now the + and - of one channel must change by accident. I don't see that happening ...

 

All 'n all there would be no way certain music requires to change the polarity of one of the speakers (or the recording is plain wrong and out of phase). It most certainly can happen that it requires inverting absolute phase, but to me -as one who is not sensitive to that- there are *other* phenomena in order that desire for this. If you can't switch it easily you will never know. Note though that you can always invert absolute phase by changing the polarity of both the speakers at the same time !

 

Peter

 

Lush^3-e      Lush^2      Blaxius^2      Ethernet^2     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

Link to comment
Share on other sites

My writing was about always having both channels the same phase to each other and that was, how I read the original post. I was talking about inverting the phase in both channels each time, so that they are in Phase to each other every time, but one time with positive absolute phase and the other time with negative absolute phase.

 

Juergen

 

Link to comment
Share on other sites

You must be right Juergen. If I now read the original post I come to that conclusion too.

I don't know why I didn't before.

 

Peter

 

Lush^3-e      Lush^2      Blaxius^2      Ethernet^2     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

Link to comment
Share on other sites

(which I only now realize after interpreting the original post correctly)

 

IMO this is very "normal", and nothing different from what I described about XXHE experiences.

Still strange though, but I guess all is operating so much on the micro level that something which I call "accuracy" can make it necessary to invert the Absolute Phase. Of course each level of "accuracy" is as bit perfect, so it is not about that.

 

It is an interesting subject.

 

Lush^3-e      Lush^2      Blaxius^2      Ethernet^2     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



×
×
  • Create New...