Question for the stereo mic array folks:

[hollywood_steve]

I need to cover a small stage with multiple singers spread out and
moving around. If I had three M50s lying around, I thought that this
might be a good application for a Decca tree, but the only available
mics will be cardioids or FIG8.

Instead of a spaced array of Left, Center and Right mics, how about
three coincident mics assigned to those same positions? An XY pair
for the Left and Right placed immediately above (or below) a forward
facing Center mic. The XY pair is panned full Left / full Right and
the ratio between the XY pair and the Center mic would give you
control over the image width similar to an MS arrangement (would that
work?, let's assume basic cardioid patterns for all three mics)

I've looked through a LOT of books that focus on stereo mic
techniques, and I've never come across any 3-way coincident arrays.
The obvious advantage would be a complete lack of any phase problems
that might impact 3 spaced mics. And for my specific situation, this
would be an extremely compact, unobtrusive 3 mic array. While I'm
waiting for the opportunity to try this out, has anyone else already
done this? Or are there reasons why it just wouldn't work and there
isn't any need to try it out?

(FWIW, I'm not trying to compete with modern, multi-mic'd productions
where ever utterance is loud and clear. I'm aiming for a simulation
of what someone might hear in the "best seat in the house." A
believable stereo image with that holds up even as singers turn and
move all over the stage)

thanks,

Steve

[Kurt Albershardt]

hollywood_steve wrote:
>
> Instead of a spaced array of Left, Center and Right mics, how about
> three coincident mics assigned to those same positions? An XY pair
> for the Left and Right placed immediately above (or below) a forward
> facing Center mic. The XY pair is panned full Left / full Right and
> the ratio between the XY pair and the Center mic would give you
> control over the image width similar to an MS arrangement (would that
> work?, let's assume basic cardioid patterns for all three mics)

Why not just use an MS array with one fo the figure-eights.

BTW, what mics are these?




> I've looked through a LOT of books that focus on stereo mic
> techniques, and I've never come across any 3-way coincident arrays.
> The obvious advantage would be a complete lack of any phase problems
> that might impact 3 spaced mics. And for my specific situation, this
> would be an extremely compact, unobtrusive 3 mic array. While I'm
> waiting for the opportunity to try this out, has anyone else already
> done this? Or are there reasons why it just wouldn't work and there
> isn't any need to try it out?

Probably because you don't need 3 coincident mics to derive a 2-channel
signal?




> (FWIW, I'm not trying to compete with modern, multi-mic'd productions
> where ever utterance is loud and clear. I'm aiming for a simulation
> of what someone might hear in the "best seat in the house." A
> believable stereo image with that holds up even as singers turn and
> move all over the stage)

I would think ORTF could handle this well if it's placed properly and
done with good mics.

[James Boyk]

<purist> You're sending mixed messages here. You say you want a legit stereo
image as a priority over close-up intelligibility. Fine. Then you say you might
have to handle signals coming from the left differently than signals from the
right. That's fine, too; but it's hardly consistent with the first goal.


If what you want is stereo, not two-channel mono, you need to get out of your
head the idea of multiple mike locations. What you use is a single coincident
pair. I suggest using MS if you have condenser mikes, and thinking of XY only if
you have ribbons. You place it back far enough that the included angle from full
left to full right is <60 degrees (+/- 30 on either side of center), or at
worst, <90 degrees. You are doing this in a good hall, so the additional
ambience you pick up by being this far back enhances the sound rather than
detracting from it. You are using superb mike preamps with resolution way down
into their nominal dynamic range (which many preamps don't really have). You are
encouraging the audience by all possible friendly means to be SILENT. And you
have arranged for hall mechanical noises to be turned off. No fans, no
fluorescents, no SCR dimmers.


Then you set your level--once--and sit back and enjoy the show.


After hitting RECORD, that is.



James Boyk

</purist>

[Jim Weld]

I agree with James Boyk in that coming up with a single point-source
position and being able to ride a specific level are incompatible ideas.
Once you change a level setting everything gets screwed-up. You may need to
use PZM technique if you want to capture everything. Or maybe even a stereo
arrangement in center with PZMs to far left and right just to pick up head
turns and way off-axis stuff. I'm assuming you're stuck with mics on the
stage apron, too close to get the angle you need for good pick-up.

Jim Weld


"hollywood_steve" > wrote in message
om...
> I need to cover a small stage with multiple singers spread out and
> moving around. If I had three M50s lying around, I thought that this
> might be a good application for a Decca tree, but the only available
> mics will be cardioids or FIG8.
>
> Instead of a spaced array of Left, Center and Right mics, how about
> three coincident mics assigned to those same positions? An XY pair
> for the Left and Right placed immediately above (or below) a forward
> facing Center mic. The XY pair is panned full Left / full Right and
> the ratio between the XY pair and the Center mic would give you
> control over the image width similar to an MS arrangement (would that
> work?, let's assume basic cardioid patterns for all three mics)
>
> I've looked through a LOT of books that focus on stereo mic
> techniques, and I've never come across any 3-way coincident arrays.
> The obvious advantage would be a complete lack of any phase problems
> that might impact 3 spaced mics. And for my specific situation, this
> would be an extremely compact, unobtrusive 3 mic array. While I'm
> waiting for the opportunity to try this out, has anyone else already
> done this? Or are there reasons why it just wouldn't work and there
> isn't any need to try it out?
>
> (FWIW, I'm not trying to compete with modern, multi-mic'd productions
> where ever utterance is loud and clear. I'm aiming for a simulation
> of what someone might hear in the "best seat in the house." A
> believable stereo image with that holds up even as singers turn and
> move all over the stage)
>
> thanks,
>
> Steve
>

[Michael Putrino]

How about trying the decca tree arrangement that's in this month's Mix
magazine (I think it's this month's issue). It uses an MS for the
center and a cardiod at each end of the tree.

Sounds like it might be just what you're after. You have the center MS
to cover the stero image and can "mix" in the end mics as you see fit.
This is not what was intended, but it might work for you.

The intension of the "improved" decca was to provide for the good
central focus of the MS (or coincident pair), while also providing
time-domain cues from the spaced pair. The article was actually adding
to this arrangement for surround sound, but...

I've never tried it, but I'd like to.

And, if you record each mic on seperate tracks, you have a lot of
options...assuming you use the MS for the center of the tree, instead
of a coincindent pair.

You've got stangard decca with the three cardioids (is that standard
decca? or does it use omnis?); you get standard MS; plus you get
"improved" decca.

Mix it the way it turns out the best.

Mike Putrino

[Kurt Albershardt]

Michael Putrino wrote:

> How about trying the decca tree arrangement that's in this month's Mix
> magazine (I think it's this month's issue). It uses an MS for the
> center and a cardiod at each end of the tree.

Sounds somewhat like what Ron Streicher does for surround stuff. Who
wrote the article?

[Carey Carlan]

(hollywood_steve) wrote in
om:

> I'm aiming for a simulation
> of what someone might hear in the "best seat in the house." A
> believable stereo image with that holds up even as singers turn and
> move all over the stage)

An ORTF pair will accomplish what you ask with the least trouble and most
flexibility. Remember that cardioids can be spread 130 degress and still
get a full center signal. That should cover your L & R wings. If you can
sit it back from the stage you'll get a better balance between center and
sides.

[Michael Putrino]

Kurt Albershardt > wrote in message >...
> Michael Putrino wrote:
>
> > How about trying the decca tree arrangement that's in this month's Mix
> > magazine (I think it's this month's issue). It uses an MS for the
> > center and a cardiod at each end of the tree.
>
> Sounds somewhat like what Ron Streicher does for surround stuff. Who
> wrote the article?

I believe Ron Streicher wrote it ;-)

[Mike Clayton]

In article >, Carey
Carlan > wrote:

> (hollywood_steve) wrote in
> om:
>
> > I'm aiming for a simulation
> > of what someone might hear in the "best seat in the house." A
> > believable stereo image with that holds up even as singers turn and
> > move all over the stage)
>
> An ORTF pair will accomplish what you ask with the least trouble and most
> flexibility. Remember that cardioids can be spread 130 degress and still
> get a full center signal. That should cover your L & R wings. If you can
> sit it back from the stage you'll get a better balance between center and
> sides.

Innaresting Carey. I like to use hypercardioids (or supercardioids when
the MK41s turn up!) in sort of ORTF/NOS. My maths isn't up to snuff on
this question so I'll ask does the change in polar pattern affect the
available included angle?

--
Mike Clayton