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Re: MS Confusion

Subject: Re: MS Confusion
From: "umashankar" umashanks
Date: Sat Jun 2, 2007 8:22 pm ((PDT))
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 poin=
t it will become mostly antiphase (and you do not want that; it is very unp=
leasant)

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"
<> 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
>




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