hello,

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.

Generic, you can think of M/S recording as just an indirect way of
recording with two coincident directional microphones ("X/Y"). Once you
dematrix the M and S signals, you'll have stereo left and right signals
representing a single point in space. So any room that can be used for
ordinary coincident stereo recording with directional microphones
should also work for mid-side recording.

It isn't necessary that the figure-8 microphone get tickled exactly the
same way on both of its axes. Orchestras aren't symmetrical, after all,
and neither are pianists or string quartets. In fact reality in general
seems rather lop-sided these days, don't you think?

--best regards

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

It'll have the same effect it does on any other recording approach; the
sound recorded will include the sound of the room. That may be a problem
in some situations, but if so your choices are to fix the room, move
elsewhere, or drop the attempt to do stereo recording and just
close-mike everything.

On Mon, 5 Sep 2005 01:00:04 -0400, wrote
(in article . com):

hello,

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.


pends on how close they are and how much is coming off of them.

Ty Ford



-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

wrote:

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

No more than it would screw up the listening at that position.

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.

An M-S recording is precisely equivalent to a coincident cardioid (X-Y)
recording, given perfect microphones. It behaves the same way and is
positioned the same way. It should sound pretty much the same.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

wrote in news:1125896404.764742.89830
@g44g2000cwa.googlegroups.com:

hello,

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.

Short answer: No.

Long answer: Ask your ears. Listen for odd reflections, level imbalance,
or change in timbre. If all that's OK, you're good. If not, move around
until what you hear is what you want to record and park your mics there.

On 9/5/05 10:52 AM, in article , "Scott Dorsey"
wrote:

wrote:

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

No more than it would screw up the listening at that position.

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.

An M-S recording is precisely equivalent to a coincident cardioid (X-Y)
recording,

Adding to Scott's contribution here that, while XY cards usually gets
assumed (not altogether incorrectly) to be aimed 90deg apart (each 45deg off
front axis), that only applies to MS when it's using a cardioid as the MID
mic, which is not at all a fair assumption. The wider your MID mic is, the
smoother your stereo imaging will be.
Never forget to listen to the MID mic alone to see what that position really
sounds like.


...given perfect microphones. It behaves the same way and is
positioned the same way. It should sound pretty much the same.

Agreed, you pick your MS mic position mainly by deciding that it's where you
like to have your head to listen to whatever you;re recording. Symmetry is
nice, but not always what you want...
Learned long ago that placing mics where things are perfectly matched can be
right where the room likes to focus all sorts of resonances...
Moving out of that zone, a little or a lot, can really clear things up.

On 9/5/05 11:01 AM,
"Carey Carlan" wrote:

... move around
until what you hear is what you want to record and park your mics there.

Ummmm Carey... Isn;t this just plain old-fashioned pre-digital-plugin crap?
With todays modern DAW tools you can model anything so that LISTENING is
really just some old-shool witchcraft that bald spectecled labcoat types and
greying ponytailed leftovers use to make themselves feel like they're
actually still doing something USEFUL?

JV The Pretengineer,
Playin Around With Sound just left of DC

Carey Carlan writes:

wrote in news:1125896404.764742.89830
:

hello,

let's say you were recording mid-side, but the side walls were
asymmetrical in some way (different distances from each other, windows
on one side, etc.). would this totally screw up the mid-side
recording?

basically, i'm wondering if side-wall symmetry is an essential
ingredient to a quality mid-side recording.

Short answer: No.

Long answer: Ask your ears. Listen for odd reflections, level imbalance,
or change in timbre. If all that's OK, you're good. If not, move around
until what you hear is what you want to record and park your mics there.

All good answers.

But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S or
a mic/bar combination that holds them properly.

If not (or if there's something screwy about any of the geometry
involved), you might need to ever so slightly time slip one of the tracks
to make the M-S work ideally.

This is a darn good reason why to record the raw M and S mic signals and
*not* record the decoded signal. You can fiddle with decoding in post. (Of
course, you'll want a decode setup in your monitor channels during
recording.)

I've had situations where mediocre-sounding M-S came fully alive with a
fractional millesecond nudge on one of the mics. If you're not blessed
with a optimized M-S mic system out of a box and instead are using a
cobbled system, it's interesting to step through some time nudging to find
the "sweet spot" for the decode.

Frank Stearns
Mobile Audio

--

But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S or
a mic/bar combination that holds them properly.

Yes and no, if you're in digital world you can time-align after you've
recorded....
Is come out interesting stuff...
I.E. "mid" mic 10ft. away and the "side" mic only 5ft.
Then, in digital world, you move the side mic "5ft." back.

Or you can try the opposite, having the side mic far and the mid mic
close....

I wouldn't do that for classical recording but it can give you some more
particular sound when you decode.
F.

Federico wrote:
But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S or
a mic/bar combination that holds them properly.

Yes and no, if you're in digital world you can time-align after you've
recorded....
Is come out interesting stuff...
I.E. "mid" mic 10ft. away and the "side" mic only 5ft.
Then, in digital world, you move the side mic "5ft." back.

Which means that stuff from the edges of the soundfield aren't properly
aligned at all, and only stuff on the center of the soundfield is coherent.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

SSJVCmag wrote:

Agreed, you pick your MS mic position mainly by deciding that it's where you
like to have your head to listen to whatever you;re recording. Symmetry is
nice, but not always what you want...

Hard to tell at this point, but often a question like this really means
"How bad is it going to be if I put the mic where I can and not
necessarily where I've determined sounds best."

On 9/5/05 11:41 AM, in article , "Frank
Stearns" wrote:

All good answers.

But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S or
a mic/bar combination that holds them properly.

If not (or if there's something screwy about any of the geometry
involved), you might need to ever so slightly time slip one of the tracks
to make the M-S work ideally.

This is a darn good reason why to record the raw M and S mic signals and
*not* record the decoded signal. You can fiddle with decoding in post. (Of
course, you'll want a decode setup in your monitor channels during
recording.)

I've had situations where mediocre-sounding M-S came fully alive with a
fractional millesecond nudge on one of the mics. If you're not blessed
with a optimized M-S mic system out of a box and instead are using a
cobbled system, it's interesting to step through some time nudging to find
the "sweet spot" for the decode.

Frank Stearns
Mobile Audio


It's GOOD to live in the age of digital...

On 9/5/05 2:18 PM, in article
, "Mike Rivers"
wrote:

... often a question like this really means
"How bad is it going to be if I put the mic where I can, and not
necessarily where I've determined sounds best."

That happens...?

Mike Rivers wrote:
SSJVCmag wrote:

Agreed, you pick your MS mic position mainly by deciding that it's where you
like to have your head to listen to whatever you;re recording. Symmetry is
nice, but not always what you want...

Hard to tell at this point, but often a question like this really means
"How bad is it going to be if I put the mic where I can and not
necessarily where I've determined sounds best."

If I don't know the room and I don't have time to explore it properly, I
will usually avoid being anywhere near the center line. All kinds of things
happen there, not just flutter echoes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

I am not saying that is coherent or "right".
I just say that is interesting....
It's something you couldn't have done before digital era...
Tha Beatles may have like that, who knows...
F.


"Scott Dorsey" ha scritto nel messaggio
...
Federico wrote:
But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S
or
a mic/bar combination that holds them properly.

Yes and no, if you're in digital world you can time-align after you've
recorded....
Is come out interesting stuff...
I.E. "mid" mic 10ft. away and the "side" mic only 5ft.
Then, in digital world, you move the side mic "5ft." back.

Which means that stuff from the edges of the soundfield aren't properly
aligned at all, and only stuff on the center of the soundfield is
coherent.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Mon, 05 Sep 2005 18:37:26 GMT, in rec.audio.pro SSJVCmag
wrote:

On 9/5/05 11:41 AM, in article , "Frank
Stearns" wrote:

All good answers.

But also with M-S, you *must* be sure that the two microphones are
time-aligned. This means that you have a stereo mic designed to do M-S or
a mic/bar combination that holds them properly.

If not (or if there's something screwy about any of the geometry
involved), you might need to ever so slightly time slip one of the tracks
to make the M-S work ideally.

This is a darn good reason why to record the raw M and S mic signals and
*not* record the decoded signal. You can fiddle with decoding in post. (Of
course, you'll want a decode setup in your monitor channels during
recording.)

I've had situations where mediocre-sounding M-S came fully alive with a
fractional millesecond nudge on one of the mics. If you're not blessed
with a optimized M-S mic system out of a box and instead are using a
cobbled system, it's interesting to step through some time nudging to find
the "sweet spot" for the decode.

Frank Stearns
Mobile Audio


It's GOOD to live in the age of digital...
Bit OT, but what does a jellyfish display show while you are trimming
the MS time difference, anything interesting?
Or does it just " click" when you get it correct?


martin

could you elaborate on m/s = xy cardioid?

i never knew that!

ironically, the recordings i've heard that i really liked have so often
been either coincident cardioid x/y or mid/side. i had no idea on the
planet they were the same thing! but now that i think about it, they
do have that same sort of "focus yet width" that i intrinsically like.

i'm talking about the cardioid and figure-8 mic being as physically
close as possible. the assymetry was to do with the walls, not by
spacing the mics away from each other. also, i would record the
figure-8 uncoded and then duplicate/phase reverse the track in the daw
to get the m/s to happen.

you do bring up an interesting idea. there's always the tricks of
doing something like time-aligning the drum overheads with the snare
drum mic. but i never thought about doing something like intentionally
spreading out the m/s mics from each other.

wrote:
could you elaborate on m/s = xy cardioid?

With M cardiod it's actually MS = XY supercardiod.

A mid cardiod will have the sensitivity pattern

M = 1 + cos(theta).

A side fig 8 will have the pattern

S = cos(theta + 90),

with theta measured positive clockwise and at zero on center.

So from the matrix

L = M + S

and

R = M - S,

then

L = 1 + cos(theta) + cos(theta + 90)

R = 1 + cos(theta) - cos(theta + 90).

Application of the identity

cos(s) + cos(t) = 2*cos(s/2 + t/2)*cos(s/2 - t/2)

gives

L = 1 + sqrt(2)*cos(theta + 45)

R = 1 + sqrt(2)*cos(theta - 45)

Thus, L is a supercardiod (-15.3 dB out of phase rear lobe)
pointing 45 degrees to the left and R is a supercardiod
pointing 45 degrees to the right. The increased ambience
from the small out of phase rear lobe may be why some prefer
MS to XY.

By varying the relative amounts of mid to side in the MS
matrix, the logical angle between L and R can be changed
(narrower with less S.) This also varies the pattern toward
a larger rear lobe as S gain gets greater and toward pure
cardiod as it goes to zero.

It should be possible to give general sensitivity
expressions for L and R in terms of the gain of the M and
that of the S in the matrix and the scale of the cos() term
in the M. I think I once derived it but can no longer
remember it.



Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

wrote:
could you elaborate on m/s = xy cardioid?

That's the whole point of the M-S thing. It gives you basically the
same single-point pickup of an X-Y array, but the center of the soundstage
is on-axis with the M mike and in the null of the S mike. This means
the center of the soundstage is going to be the least colored place in
the soundfield. With an X-Y, the center of the soundstage is off-axis on
both mikes.

ironically, the recordings i've heard that i really liked have so often
been either coincident cardioid x/y or mid/side. i had no idea on the
planet they were the same thing! but now that i think about it, they
do have that same sort of "focus yet width" that i intrinsically like.

I personally prefer the slight interchannel phase differences that you
get with ORTF. You can't hang an ORTF array off the back of a motorcycle
like you can with a single-point stereo mike, though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
the center of the soundstage is going to be the least colored place in
the soundfield. With an X-Y, the center of the soundstage is off-axis on
both mikes.

That's the best short description of "why MS" I've seen. Thanks, Scott.

(Now if I could find a good cheap MS... well, I can dream, can't I?)

Joe Kesselman wrote:
Scott Dorsey wrote:
the center of the soundstage is going to be the least colored place in
the soundfield. With an X-Y, the center of the soundstage is off-axis on
both mikes.

That's the best short description of "why MS" I've seen. Thanks, Scott.

(Now if I could find a good cheap MS... well, I can dream, can't I?)

You can. Pick whatever good cardioid you already have, then add a
Beyer M-130 to it. Well, it's not all THAT cheap. But it's not a
fortune, and it sure sounds good, even if higher frequencies will tend to
skew toward the center of the soundfield.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."