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Re: MS Confusion

Subject: Re: MS Confusion
From: "scottsherk27" scottsherk27
Date: Sun Jun 3, 2007 6:14 am ((PDT))
Thanks.  This explains all my observations and confusion.

Scott


--- In  umashankar <> 
wrote:
>
> that is exactly what should happen. when you  try to increase the S 
signal beyond 100 % what you are effectively trying to increase is 
the stage width, to be greater than the original stage width. and the 
way that is achieved is to add out of phase components from one side 
to the other. at some point it will become mostly antiphase (and you 
do not want that; it is very unpleasant)
> 
> umashankar      
> 
> 
> ----- Original Message ----
> From: scottsherk27 <>
> To: 
> Sent: Sunday, June 3, 2007 7:55:46 AM
> Subject: [Nature Recordists] Re: MS Confusion
> 
> 
> Thanks for all the useful information.  (I understand somewhat 
more, 
> but I had the same diffficulty trying to understand bond yields 
> curves.)  After playing around with some files I have discovered 
that 
> the out-of-phase that I was seeing on Audition's Phase Analyzer 
> happens when I increase the S-width in both the MDA and Voxengo 
plug-
> ins.  If I decode at 100% for M and S, the phasing seems fine, but 
> registers out of phase with an increase in S.  Is this 
explainable?  
> 
> Scott
> 
> 
> 
> --- In  "John Lundsten" 
> <john.lundsten@> wrote:
> >
> > Scott wrote
> > > I can't seem to wrap my head around MS and have uncovered a 
> confusing
> > > issue. I have discovered that after decoding my MS recordings 
(MDA
> > > plug-in,Voxengo MSED, or Audition) they are 100% out of phase 
> according
> > > to Audition's Phase Analyzer. When I invert one channel, they 
> return
> > > into phase. Where in my chain would I inadvertently be 
inverting 
> the
> > > phasing? Or does decoded MS always have an inverted phasing?
> > 
> > Not familiar with Plug-ins you mention. The Audition one is/ can 
be 
> rather 
> > confusing & its awful to use IMO. Suggest Kelly industries Stereo 
> Tools, 
> > free & great VST plug.
> > When you say 100% out of phase this suggests mono to me all 
stereo 
> has some 
> > out of phase info.
> > Q what does it sound like when you sum the L&R out IE mono it?
> > Q are you using the Phase Analyzer in L/R mode? {not a good idea 
in 
> MS or 
> > Spin mode}
> > Q Are you are decoding on the Multitrack page?
> > If you have a 2 chan file running (IE you haven't converted your 
> file into 2 
> > mono files) the balance control will need to be centered. 
> Conversely if 
> > using 2 mono files they would need to be panned hard L & R
> > 
> > 
> >  "Tim Nielsen" Wrote
> > 
> > > It shouldn't be that way. MS 'should' be completely in phase and
> > > fully mono compatible.
> > 
> > Agree 100%
> > >
> > > Are you positive you fed the center mic into the 'left' channel 
of
> > > the MS plugin, and the figure-8 to the 'right' side? I'm not 
sure
> > > doing it the other way would cause the phase issues you're 
seeing,
> > > but they do have to be set correctly.
> > No, that's not it; Actually it would sound surprisingly similar, 
> there will 
> > be a problem when (if) you mono'd the output however, you would 
> only hear 
> > the Fig8, IE ambience only.
> > 
> > A proper MS decode will send the M to both L&R [same amount/vol, 
no 
> messing 
> > with polarity]
> > And the S to both too, but with R getting a phase/polarity 
flipped 
> version 
> > of S. [again same amount to both L&R chan but this can be the 
> amount you 
> > want to get the stereo width desired ]
> > The only way to mess up the phase of the decoder output is not 
> follow the 
> > above
> > So with a proper de-code if you mono the output the S signal 
> cancels ( or 
> > the M if you got your M & S swapped/confused)
> > 
> > The effect of flipping either M or S on the way in would be ONLY 
to 
> swap the 
> > L R sense.  There is an assumption or convention that the S mic 
> should be 
> > mounted with the + phase to the left - if the S mic were mounted 
> the other 
> > way round all that happens is the stereo field is swapped in a 
L/R 
> sense.
> > 
> > >
> > > Are you sure your mic capsules were coincedent? For MS to work
> > > properly, the capsules need to be aligned in the vertical plane.
> > >
> > Reasonable point but it sounds like there's  a more drastic prob 
> than a 
> > slight mangling of the HF phase that would cause.
> > 
> > Hope that helps
> > John Lundsten
> >
> 
> 
> 
> 
> "While a picture is worth a thousand words, a 
> sound is worth a thousand pictures." R. Murray Schafer via Bernie 
Krause
> 
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