> On 4 Oct 2018, at 16:10, Duncan Whitley [naturer=
ecordists] <> wrote:
>
> Hi all
>
> Wondering if anyone with mid-side knowledge can help me out on this one. =
I made some recordings last night and in the dark mistakenly plugged the S =
into the left-channel of my recorder, and the M into the right. Usually thi=
s wouldn=92t be problem for me to rectify as I tend to record in MS on disc=
rete mono channels and decode later - however, on this occasion I decoded t=
o XY stereo inside the matrix box of the mic.
>
Fortunately MS encoding/decoding is a linear, reversible operation.
L =3D (M + S) / 2
R =3D (M - S) / 2
If you have exchanged M and S you have two options.
1) Reverse the phase of the R you decoded from the exchanged ; and S
2) You can undo the process by getting the resultant XY decoding back to MS=
.. After doing that, exchange M and S and decode again
Something like:
M=97-\. /=97=97-\
Convert to XY =97-- Convert to XY again
S =97-/. \=97=97/
>
> Is it possible to recover the original M and S channels from the XY stere=
o decoded recordings? My intuition says =93no=94, but wondered if anyone ha=
d any knowledge on this.
>
> It=92s easy enough to derive the M and S from the XY stereo when the chan=
nels have been decoded to stereo correctly in the 1st place, but I=92m not =
sure in this case if it still works.
>
> Thoughts?
>
> Duncan
>
>
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