Cardioids crossed at 90 degrees

Discussion in 'rec.audio.pro' started by James Boyk, Aug 21, 2003.

  1. Sugarite

    Sugarite Guest

    > Sugarite wrote: Firstly, post processing is always required to tame a
    location
    > recording to be even remotely realistic.
    >
    > You must work in an entirely different genre from anything I've

    experienced. Granted, I do only a very limited kind of thing; but it
    involves *avoiding* all unnecessary processing and for that matter all
    unnecessary gain stages, to keep the sound as pure as possible.

    Yeah, I work in pro audio, not sure what you work in. It doesn't take Ben
    Hogan to illustrate how the process of sound reproduction is a very
    unnatural act, and therefore will require invasive procedures in order to
    seem natural. (Ben said the same thing of a golf swing and his book is
    pretty much a bible to pro golfers) For example, the use of microphones and
    speakers by their very nature is expansive, so by doing nothing you're
    actually in effect applying an expander. The signal is "pure" but the sound
    has been significantly altered. And if you think the human auditory system
    involves no significant processing by the brain, think again. (pardon the
    pun)

    > > ...The widening of a 90 degree cardioid XY pair is just one of many

    processes that must be done,
    >
    > You convert XY to MS, increas the proportion of S, then convert back to

    XY?

    Actually I use Waves Stereo Imager, which does what I need in the digital
    domain, presumably by that process. I know what you're going to say next, I
    should avoid the extra process and record in MS. I don't like the idea of a
    side channel running through any analog gear for fear that some expansion or
    compression might occur disproportionate to the mono channel, which can
    really warp the stereo image. That's what generally happens if you record
    MS with a tube preamp, the saturation effect makes the middle wider and
    brings the sides in. Any dynamics manipulation applied to MS must be keyed
    by the sum signal, which is impossible to do with any colored dual preamp.
    I prefer using a tube preamp in XY at the cost of the extremely minor extra
    process.

    > > ...and even though another mic
    > > format might be better suited to rendering more natural imaging before

    post,
    > > it's a minor issue compared to other factors, one of which is proper
    > > rejection. I don't claim to know exactly why 90 degree coincident

    cardioids
    > > can offer the best imaging, but I'm going to offer a plausible

    explanation
    > > for the specific circumstances of a live concert, which can also apply

    to
    > > other environments.

    >
    > Live rock concert, that is.


    Anything with sound reinforcement actually, so virtually any performance
    before a significant audience

    > I'd love to hear "before" and "after" examples.


    I think I've done enough already.

    > > Here's an example of this technique:

    http://www.thetrewsmusic.com/media/mp3/060703-tow.zip
    >
    > Can you put this on a web site instead?


    Uh, that is a website (http). Sorry it's in zip format (expands to an mp3),
    not sure what the webmaster is thinking there.

    > > ...figure-8's would slew the rear imaging and leave a gap up front.

    >
    > I don't get this statement about fig-8's.


    Well that process wouldn't be applied to fig-8's anyways, don't worry about
    it.

    > > ...AFAIK the cardioid XY pattern is the only way to acheive this
    > > effectively, probably because the 90 degree angle represents the

    separation
    > > between the two independent component vectors of the forces imposed on a
    > > single positon in two dimensions, hence the term "XY", much like the

    grooves
    > > on stereo LP's....

    >
    > I can't follow this.


    It's pretty basic physics, do a websearch on "component vectors" and you'll
    probably see some diagrams, it's also important to sailing theory.

    > Huh? A "stereo" listens to your recordings? No, a human listens. We

    certainly are ALWAYS recording for a human auditory system.

    Yes, a stereo listens, that's exactly what I said, word for word...
    </sarcasm>

    I was illustrating how our responsibility stops at the CD, so we get paid no
    matter what species is placed in front of the speakers. It's really just an
    issue of semantics, and just my opinion. Another more important aspect of
    what I said is that the human auditory system is not the template by which
    all recording devices and techniques should be based. It is an analysis
    tool, not a sound reproduction tool, and is the result of the evolution of
    our bodies which have many other systems, each comprimised to accommodate
    each other for the most effective total package. Microphones are not
    snail-shaped, full of liquid, with hairs lining the interior, for example.

    Ears actually have thousands of sensors, and it's been theorized that each
    covers a very small frequency range, with only marginal overlap. What we
    hear might actually be a tone generator in our brain that is triggered by
    those sensors like a keyboard, except with proper phase information. You
    want to try emulating that? That theory would be consistent with what's
    known about our vision system, which is a picture generated by the brain
    based on the information gathered by the eyes. Science hasn't produced any
    reliable explanation to date, so who knows.

    > And Blumlein showed why the right way to do that is to use coincident

    fig-8's (or spaced omnis with the "Blumlein shuffler," which no one seems to
    use).

    I never said there was a right or wrong way, in fact I would disagree with
    anyone claiming there was a right or wrong way. Different techniques are
    used, resulting in different effects. It's the difference between a craft
    and a science. The coincident fig-8 format is well-suited to a realistic
    representation of an environment which offers a mic position which is *both*
    where the best tone and balance between instruments, voices, and ambience
    can be found *and* the ideal position to be recreated on a stereo.
    Unfortunately, I have *never* encountered such an environment where sound
    reinforcement was involved. Every time the sound is better at a significant
    distance from the performers, but listeners at home want to feel close to
    the action. Just like a macro lens at a distance can make different objects
    seem closer to the same distance away from the camera, my way lets you seem
    close without the imbalances caused by proportionally greater differences in
    proximity. I'm essentially zooming in from afar to help keep certain
    aspects from upstaging others.

    Actually yeah, that's the ticket right there. I can't explain it any better
    than that. If that doesn't convince you of it's potential, then don't
    bother trying it, you won't know how to work with it in post.

    > > ...AFAIK nobody makes a CD player that plugs directly into the
    > > cerebral cortex. A stereo and the listener's ears do their part on their
    > > own and I see no reason to make special accommodations for this

    particular
    > > aspect. Coincident mics pick up the stereo image found at one position,
    > > then a properly configured stereo allows the listener to assume that
    > > positon. It is impossible for a listener to be in two positions, and

    also
    > > impossible for a stereo to reproduce two postions, so having mics in
    > > different positions generally makes about as much sense as putting legs

    on a
    > > car.

    >
    > Well, forgive me, but this is a psychoacoustically naive point of view.

    Can't it be enough just to say, "Coincident works for me"? There's no need
    to argue deep perceptual issues.

    Too late. But I fail to see your point. I've devised a technique from
    hundreds of hours of experimentation using scientific principles you
    apparently don't comprehend, while you suggest mimicking what happens to be
    on our heads and leaving it pretty much as-is. And it's ME that's naive?!
    Incompetence I can forgive, but hypocrisy and conceit aren't so easy...
  2. Sugarite <nobody@home.com> wrote:

    > Yeah, I work in pro audio, not sure what you work in.


    ahem.

    > Actually I use Waves Stereo Imager, which does what I need in the digital
    > domain, presumably by that process. I know what you're going to say next, I
    > should avoid the extra process and record in MS. I don't like the idea of a
    > side channel running through any analog gear for fear that some expansion or
    > compression might occur disproportionate to the mono channel, which can
    > really warp the stereo image. That's what generally happens if you record
    > MS with a tube preamp, the saturation effect makes the middle wider and
    > brings the sides in. Any dynamics manipulation applied to MS must be keyed
    > by the sum signal, which is impossible to do with any colored dual preamp.
    > I prefer using a tube preamp in XY at the cost of the extremely minor extra
    > process.


    Right, you wouldn't want to mess up the "imaging" in a recording of a
    PA.

    > > Live rock concert, that is.

    >
    > Anything with sound reinforcement actually, so virtually any performance
    > before a significant audience


    Have you ever been to a real concert? Not one where you sit a quarter
    mile away from the band and have the music piped over to you. You
    know, a real concert where you sit in a room with some musicians and
    hear the sounds coming out of their instruments. You know, a CONCERT?
    It could be in a little coffee shop or pub with a jazz trio or a solo
    classical guitar, or it could be a huge auditorium with a really loud
    fat lady. Or a symphony.

    To pretend that you're some excessively qualified authority on live
    recording techniques because you have refined your approach to setting
    a pair of microphones in front of PA speakers in this forum, where guys
    like James Boyk (who knows what live music sounds like) hang out just
    makes you sound, well, dumb. Sorry.

    Dude, you record PA speakers. Quit giving advice to people who record
    instruments.


    ulysses
  3. Sugarite <nobody@home.com> wrote:

    > It doesn't take Ben
    > Hogan to illustrate how the process of sound reproduction is a very
    > unnatural act, and therefore will require invasive procedures in order to
    > seem natural.


    And some folks make a successful capture that generally obviates
    shitloads of "necessary" post production. The more natural the music
    itself the easier that is. I think Scott Fraser works in por audio, too,
    but what do I know.

    --
    ha
  4. Sugarite

    Sugarite Guest

    > << Firstly, post processing is always required to tame a location
    recording to
    > be even remotely realistic.
    >
    > Post processing is never necessary if the initial recording was done

    correctly.

    Well sure, you could just do the post-processing during the recording, but
    why?

    I hope you're not implying that a recording done with only a pair of mics
    and a neutral preamp would not benefit from further processing. That's just
    not how it works.

    > <<Most PA speakers at music venues are mounted parallel to each other, so

    the
    > mic has to be towards the rear of the room to get decent direct sound from
    > the horns especially.>>
    >
    > If this is indeed the case you are dealing with an improperly set up sound
    > system. While this is very likely true in many venues, I wouldn't base a

    theory
    > around bad sound system design.
    > Scott Fraser


    Another flawed blanket statement. First let's look at the use of the word
    "improperly" in the first sentence. PA's are set up to distribute sound to
    a mass audience, and generally not to provide an ideal recording
    environment, so do you mean that it's improper for recording, or improper in
    general?

    Either way, I disagree with "bad system design" rendering any theory
    invalid. Even if the system is critically flawed, the recording technique
    could still demonstrate its effectiveness by rendering a realistic
    representation of the flawed system. And if you're going to limit the
    venues you record to those without very expansive compression horns and
    insufficient or no room tuning (to name a few issues) then you're not going
    to do much recording, period.

    What I described is only one aspect to my audience recording technique
    anyway. There's lots of tricks to deal with sound systems that aren't
    condusive to recording. That's where the real fun begins! One room I've
    managed to "conquer" has a full twin-turbo-prop airplane suspended from the
    ceiling directly between the two main speaker columns, which of course are
    mounted in parallel. By isolating one speaker column (it's a mono mix
    anyway) from the balcony and pointing the mic in a certain oblique direction
    I can get a reasonably balanced audience response and even get some stereo
    information from the stage sound. It isn't 100% consistent with the
    "actual" sound of the venue, but it's a realistic impression nonetheless.
  5. ScotFraser

    ScotFraser Guest

    << Well sure, you could just do the post-processing during the recording, but
    why?>>

    Or set up in a way that doesn't require any further signal manipulation to get
    what you're after.

    <<I hope you're not implying that a recording done with only a pair of mics
    and a neutral preamp would not benefit from further processing. That's just
    not how it works.>>

    I hope you're not implying that it's not possible to record with just a pair of
    mics & a neutral preamp with results that need no further processing.

    > <<Most PA speakers at music venues are mounted parallel to each other, so

    the
    > mic has to be towards the rear of the room to get decent direct sound from
    > the horns especially.>>
    >
    > If this is indeed the case you are dealing with an improperly set up sound
    > system. While this is very likely true in many venues, I wouldn't base a

    theory
    > around bad sound system design.


    <<Another flawed blanket statement. >>

    You should talk.

    << First let's look at the use of the word
    "improperly" in the first sentence. PA's are set up to distribute sound to
    a mass audience, and generally not to provide an ideal recording
    environment, so do you mean that it's improper for recording, or improper in
    general?>>

    If, as you say, you need to back off into the diffuse field to get a decent
    picture of the PA sytem, then the system is improperly setup by virtue of not
    providing adequate coverage in the direct field. If your mics are not in the
    angle of coverage of the horns in the front half of the room, neither are a lot
    of audience members.

    << if you're going to limit the
    venues you record to those without very expansive compression horns and
    insufficient or no room tuning (to name a few issues) then you're not going
    to do much recording, period.>>

    Guess it all depends on your clientele. I've heard any number of spectacular
    location recordings done by European broadcasters of live concerts I've mixed
    FOH. They most definitely don't mic the PA from the back of the hall.

    <<What I described is only one aspect to my audience recording technique
    anyway. >>

    What you described are a bunch of assumptions apparently based on worst case
    scenarios, but which are in no way absolutes.




    Scott Fraser
  6. James Boyk

    James Boyk Guest

    Sugarite wrote:

    > Yeah, I work in pro audio, not sure what you work in.


    I've been a member of NARAS in 4 categories, but I guess this doesn't make me a "pro." For credits as performer/engineer/producer for Sheffield Lab and Performance Recordings, see http://www.performancerecordings.com/albums.html . For research/teaching, se
    e http://www.its.caltech.edu/~musiclab/ . For writing, see http://www.cco.caltech.edu/~boyk/ARTICLES.HTM .



    > ...the process of sound reproduction is a very unnatural act, and therefore will require invasive procedures in order to
    > seem natural.


    This is a dramatic assertion which in my experience is false. Perhaps it's true with the kind of performances you record.



    > For example, the use of microphones and speakers by their very nature is expansive, so by doing nothing you're
    > actually in effect applying an expander.


    Where on Earth do you get this? Some speakers do slightly dynamically expand burst signals in certain frequency ranges; others compress slightly; yet others don't do either, at least not within quite a wide dynamic range.




    >>>...The widening of a 90 degree cardioid XY pair is just one of many

    > processes that must be done,



    >>You convert XY to MS, increas the proportion of S, then convert back to XY?



    > Actually I use Waves Stereo Imager, which does what I need in the digital
    > domain, presumably by that process. I know what you're going to say next, I
    > should avoid the extra process and record in MS.


    If using condensers, you should use MS for an entirely different reason, which I've described in other threads.



    > ...I don't like the idea of a side channel running through any analog gear for fear that some expansion or
    > compression might occur disproportionate to the mono channel, which can
    > really warp the stereo image.


    I don't know why you think compression/expansion are normal side effects of linear amplification.



    >...That's what generally happens if you record MS with a tube preamp,

    the saturation effect makes the middle wider and brings the sides in.

    I challenge you to show an example of this.



    > ...Any dynamics manipulation applied to MS must be keyed
    > by the sum signal, which is impossible to do with any colored dual preamp.
    > I prefer using a tube preamp in XY at the cost of the extremely minor extra
    > process.



    What "extra process"?



    >>>...and even though another mic format might be better suited

    to rendering more natural imaging before post, it's a minor issue
    compared to other factors, one of which is proper rejection.
    I don't claim to know exactly why 90 degree coincident cardioids can offer the best imaging,


    The reason you don't know is that no one knows. No one *can* know, because 90-coincident-cardioids *do not* offer the best imaging!




    >>>...figure-8's would slew the rear imaging and leave a gap up front.


    >>I don't get this statement about fig-8's.


    > Well that process wouldn't be applied to fig-8's anyways, don't worry about it.



    *You* made the statement about figure-8's; now I'm asking what you meant by it. Are you now saying your statement was meaningless?



    > It's pretty basic physics, do a websearch on "component vectors" and

    you'll probably see some diagrams, it's also important to sailing theory.

    Gosh, thanks; I know the basic physics. What I can't understand is your statement about "slewing the rear imaging" and "leaving a gap up front."



    > I was illustrating how our responsibility stops at the CD, so we get paid no
    > matter what species is placed in front of the speakers.



    Well, here's a fundamental disagreement: I feel that my responsibility stops when the listener is satisfied, whether in the concert hall or the home.



    > ...It's really just an issue of semantics, and just my opinion. Another more important aspect of
    > what I said is that the human auditory system is not the template by which
    > all recording devices and techniques should be based. It is an analysis
    > tool, not a sound reproduction tool, and is the result of the evolution of
    > our bodies which have many other systems, each comprimised to accommodate
    > each other for the most effective total package. Microphones are not
    > snail-shaped, full of liquid, with hairs lining the interior, for example.
    > Ears actually have thousands of sensors, and it's been theorized that each
    > covers a very small frequency range, with only marginal overlap. What we
    > hear might actually be a tone generator in our brain that is triggered by
    > those sensors like a keyboard, except with proper phase information. You
    > want to try emulating that? That theory would be consistent with what's
    > known about our vision system, which is a picture generated by the brain
    > based on the information gathered by the eyes. Science hasn't produced any
    > reliable explanation to date, so who knows.



    This is a VERY confused account of something that's anyway irrelevant to the issue. Satisfying the human listener has zero to do with emulating the listener's ear/brain system. It has to do with providing *to* that system an acoustic signal close enough to
    the original to give pleasure. "Close enough," in this context, is defined BY the ear/brain system.




    >>And Blumlein showed why the right way to do that is to use coincident

    > fig-8's (or spaced omnis with the "Blumlein shuffler," which no one seems to
    > use).



    > I never said there was a right or wrong way, in fact I would disagree with
    > anyone claiming there was a right or wrong way.



    I doubt that you've heard the comparisons, then.



    > ...Different techniques are used, resulting in different effects. It's the difference between a craft
    > and a science. The coincident fig-8 format is well-suited to a realistic
    > representation of an environment which offers a mic position which is *both*
    > where the best tone and balance between instruments, voices, and ambience
    > can be found *and* the ideal position to be recreated on a stereo.



    I don't follow the last phrase of this.



    > Unfortunately, I have *never* encountered such an environment where sound
    > reinforcement was involved. Every time the sound is better at a significant
    > distance from the performers, but listeners at home want to feel close to
    > the action. Just like a macro lens at a distance can make different objects
    > seem closer to the same distance away from the camera, my way lets you seem
    > close without the imbalances caused by proportionally greater differences in
    > proximity. I'm essentially zooming in from afar to help keep certain
    > aspects from upstaging others.


    > Actually yeah, that's the ticket right there. I can't explain it any better
    > than that. If that doesn't convince you of it's potential, then don't
    > bother trying it, you won't know how to work with it in post.



    Poor me.


    *

    >>Well, forgive me, but this is a psychoacoustically naive point of view.

    > Can't it be enough just to say, "Coincident works for me"? There's no need
    > to argue deep perceptual issues.



    > Too late. But I fail to see your point.



    I know.



    > ...I've devised a technique from hundreds of hours of experimentation

    using scientific principles you apparently don't comprehend, while you
    suggest mimicking what happens to be on our heads and leaving it pretty
    much as-is. And it's ME that's naive?! Incompetence I can forgive, but
    hypocrisy and conceit aren't so easy...


    This is hilarious and there's no point continuing. But if you try to name just one of the "scientific principles," you'll find that no such principles are involved. Your "system," as you call it, may indeed work fine for what you're doing. That's fine; but
    there's no need to elevate it to the status of science.



    James Boyk
  7. Sugarite wrote:
    >
    >>> ...The widening of a 90 degree cardioid XY pair is just one of many
    >>> processes that must be done,

    >>
    >> You convert XY to MS, increas the proportion of S, then convert back
    >> to XY?

    >
    > Actually I use Waves Stereo Imager, which does what I need in the digital
    > domain, presumably by that process.


    The wording of this statement doesn't seem to imply a deep understanding
    of those "scientific principles" you claim to hold so dear. Have you
    read any of Alan Blumlein's papers, or even Ron Streicher's book?



    > I know what you're going to say next, I
    > should avoid the extra process and record in MS. I don't like the idea of a
    > side channel running through any analog gear for fear that some expansion or
    > compression might occur disproportionate to the mono channel, which can
    > really warp the stereo image.


    One of the primary advantages of carrying the M & S signals through the
    production (often broadcast) chain separately is the reduction of image
    shifts caused by small phase differences between L & R.
  8. Sugarite wrote:
    >
    > I hope you're not implying that a recording done with only a pair of mics
    > and a neutral preamp would not benefit from further processing. That's just
    > not how it works.


    Many of us view 'further processing' as something to try and avoid. We
    find that by changing our mic choice and placement we are able to
    faithfully capture the event with little or no processing. Sometimes we
    need (or want) more manipulation but w3e certainly don't accept it as a
    requirement.
  9. Scott Dorsey

    Scott Dorsey Guest

    Sugarite <nobody@home.com> wrote:
    >
    >I hope you're not implying that a recording done with only a pair of mics
    >and a neutral preamp would not benefit from further processing. That's just
    >not how it works.


    If it was done properly, in a good room, it certainly would not.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  10. Mike Rivers

    Mike Rivers Guest

    In article <bi6q6i$k1h$1@naig.caltech.edu> boyk@caltech.edu writes:

    > One of the requirements is that, as the source moves across the stage, the sum
    > of the two channels has to stay constant. With figure-8's, it's pretty close
    > to doing so; and very close with +/- 30 degrees of center.


    > The cardioid differs a lot from this; in particular, the two channels add up to
    > too much at and near the center.


    This is why I learned "cardioids at 110 degrees, hypercardioids at 90
    degrees" at least as a starting point.




    --
    I'm really Mike Rivers - (mrivers@d-and-d.com)
  11. WillStG

    WillStG Guest

    << James Boyk boyk@caltech.edu >>
    << You can judge only by listening. The question was whether
    90-coincident-cardioids image correctly. They don't; they don't come close. >>

    It is interesting to me that the reason given for that is because of
    having too much center image though, mainly because this weekend I have been
    having the opposite problem. In a very large hall with a 50' ceiling my
    problem has been the main XY pair wasn't _narrow_ enough on the Concert Grand.
    WelI ok I do have two spaced AB pairs of B&K 4006's up, but I just started with
    the main pair of MKH40's (started in ORTF, then switched to XY.) Still too
    wide, the sound really only came together when we panned in the XY pair (with
    the Omni outrigger's up), that really brought a lot of depth and 3
    dimensionality to the soundstage. The piano really projects much much wider
    in a larger space than it does in a smaller environment like Concert Stage, at
    least that's been what I have been experiencing this weekend...


    Will Miho
    NY Music & TV Audio Guy
    Fox And Friends/Fox News
    "The large print giveth and the small print taketh away..." Tom Waits
  12. James Boyk

    James Boyk Guest

    WillStG wrote: > ...In a very large hall with a 50' ceiling my problem
    has been the main XY pair wasn't _narrow_ enough on the Concert Grand.
    ....I do have two spaced AB pairs of B&K 4006's up, but I just
    started with the main pair of MKH40's (started in ORTF, then switched
    to XY.) Still too wide, the sound really only came together when we
    panned in the XY pair (with the Omni outrigger's up), that really
    brought a lot of depth and 3 dimensionality to the soundstage.


    Did you mean to write "only came together when we panned in the AB pair"?


    This is interesting. I have no idea why 90-coinc.-cardioids would be too wide. You didn't by any chance record a bit with just that pair?


    James Boyk
  13. WillStG

    WillStG Guest

    << James Boyk boyk@caltech.edu >>
    << Did you mean to write "only came together when we panned in the AB pair"? >>

    Yes.

    << This is interesting. I have no idea why 90-coinc.-cardioids would be too
    wide. You didn't by any chance record a bit with just that pair? >>

    Yes, we recorded the main XY pair and the two AB pairs separately on 6
    tracks, and a balance of them on another pair of tracks. There's also a couple
    of tracks of SM2 in cardiod that we didn't mix in.



    Will Miho
    NY Music & TV Audio Guy
    Fox And Friends/Fox News
    "The large print giveth and the small print taketh away..." Tom Waits
  14. James Boyk

    James Boyk Guest

    WillStG wrote:
    > << James Boyk boyk@caltech.edu >>
    > << Did you mean to write "only came together when we panned in the AB pair"? >>
    >
    > Yes.
    >
    > << This is interesting. I have no idea why 90-coinc.-cardioids would be too
    > wide. You didn't by any chance record a bit with just that pair? >>
    >
    > Yes, we recorded the main XY pair and the two AB pairs separately on 6
    > tracks, and a balance of them on another pair of tracks. There's also a couple
    > of tracks of SM2 in cardiod that we didn't mix in.



    Care to send me a couple of minutes of the XY cardioids on a CD? I'd be vy interested to hear the imaging.


    If so, write me off-group & I'll supply my address.


    James Boyk
  15. WillStG

    WillStG Guest

    << << James Boyk boyk@caltech.edu >> >>
    << << This is interesting. I have no idea why 90-coinc.-cardioids would be too
    wide. You didn't by any chance record a bit with just that pair? >> >>

    I suppose it's possible that 6' out (7'up) was too close? But by
    comparison on a small Concert hall stage ( Merkin Hall ) there is a very
    obvious very stereo "sweet spot" about 2 1/2' feet wide, 4 to 5 feet up and 3
    feet out in the center of their 9" Concert Grands when placed center stage. I
    could see in that situation for the first time some kind of sense in the
    DPA/B&K placement advice of 40-60 centimeters apart and 1 to 2 meters away for
    their omnis in AB. But on the floor of Manhattan Center under the (actually 60
    foot) curved ceiling a 9' Steinway just projects totally differently somehow.
    And my brother and I can't remember ever observing a classical or filmscore
    session that used 4006's that close together in that large hall, on a piano or
    on an Orchestra.

    Panning in the XY pair gave a clearer center image and a depth of
    soundstage that was lacking with the XY pair hard panned. Actually panning
    them in went against the purist approach I was trying to take, but I had to
    admit to my brother it was an improvement. Perhaps we'll try just moving the
    main pair further away from the piano next time though.

    We had the XY MKH40's 5-6 feet out and 7 feet up, a pair of 4006's a little
    higher up about the same distance from the piano and 10 feet apart (placed
    there because that's where the sound was), and another pair of 4006's with the
    black grids on them 13 feet up,16' out and about 17 or 18 feet apart.

    Ok, a 2:1 ratio isn't optimal theoretically. It worked pretty well
    though...


    Will Miho
    NY Music & TV Audio Guy
    Fox And Friends/Fox News
    "The large print giveth and the small print taketh away..." Tom Waits
  16. WillStG

    WillStG Guest

    << James Boyk boyk@caltech.edu >>
    << Care to send me a couple of minutes of the XY cardioids on a CD? I'd be vy
    interested to hear the imaging.

    If so, write me off-group & I'll supply my address. >>

    It's not even edited yet! But I'll ask the artist when I see her later this
    week. This weekend was very ambitious, 19 pieces in two days. Right now, I'm
    whipped and have had enough Classical piano for a couple of days...


    Will Miho
    NY Music & TV Audio Guy
    Fox And Friends/Fox News
    "The large print giveth and the small print taketh away..." Tom Waits
  17. I have a theory.

    Forget about cardioids for a moment and think of figure-8s at 90 degrees. The
    instruments "facing" each mic will be reproduced as coming directly from the
    corresponding playback speaker. Therefore, reducing the angle between the mics
    widens the playback image, and vice-versa. (I have actually done this when
    recording, varying the angle to adjust the apparent width of the image.)

    The same principle roughly applies to a pair of cardioids, though the effect
    would be less extreme, as a cardioid's response does not fall off to the sides
    as rapidly as a figure-8's.

    This is obviously not a complete or fully correct explanation, as it doesn't
    consider how the anti-phase elements of a cardioid or figure-8 output affect the
    imaging, but I think it's broadly correct.


    > I have no idea why 90-coinc.-cardioids would be too wide.
  18. Mike Clayton

    Mike Clayton Guest

    In article <20030901030242.20786.00000389@mb-m21.aol.com>, willstg@aol.com
    (WillStG) wrote:

    > << James Boyk boyk@caltech.edu >>
    > << Care to send me a couple of minutes of the XY cardioids on a CD? I'd be vy
    > interested to hear the imaging.
    >
    > If so, write me off-group & I'll supply my address. >>
    >
    > It's not even edited yet! But I'll ask the artist when I see her later this
    > week. This weekend was very ambitious, 19 pieces in two days. Right

    now, I'm
    > whipped and have had enough Classical piano for a couple of days...



    I don't suppose you considered M/S Will? Would have liked to hear what you
    could have done with it in post.

    --
    Mike Clayton
  19. Mike Rivers

    Mike Rivers Guest

    In article <vl63jcha7sfc06@corp.supernews.com> williams@nwlink.com writes:

    > Forget about cardioids for a moment and think of figure-8s at 90 degrees. The
    > instruments "facing" each mic will be reproduced as coming directly from the
    > corresponding playback speaker. Therefore, reducing the angle between the mics
    > widens the playback image, and vice-versa.


    This is true, and it works for cardioids also. It's counter-intuitive
    until you either think about it real hard or just try it.

    But like all other near-coincident techniques, you can go too far far
    too quickly. The extreme theoretical case is the two mics, one panned
    hard left and the other panned hard right, separated by a small
    distance. That gives you a comb filtered hole in the middle.



    --
    I'm really Mike Rivers - (mrivers@d-and-d.com)
  20. Actually, Tony Faulkner has done this with forward-facing figure-8s, about 8"
    apart.

    > But like all other near-coincident techniques, you can go too
    > far too quickly. The extreme theoretical case is two mics, one
    > panned hard left and the other panned hard right, separated
    > by a small distance. That gives you a comb-filtered hole in the
    > middle.

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