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What is the problem with using ORTF for a recording for film or television?

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I have read statements on ramps to the effect that producers insist that stereo recordings of ambient sound be done XY or MS to ensure mono compatibility because large numbers of people still own mono television sets.  A few questions:

Does this mean that nobody recording ambient sound for movies or television uses ORTF? (In these same ramps discussions, I have seen suggestions that ORTF is used, and that in the real as distinct from theoretical world, it works.)

What exactly is it about an ORTF recording, when received in a mono receiver, that is nasty?

Does this mean that broadcasters are broadcasting in both stereo and mono, or that they are broadcasting in stereo, but that quality of the stereo broadcast, when received on a mono TV or radio, depends on whether it was originally recorded XY or MS rather than ORTF? Or is there something else at play?

On a semi-related question, has anyone read The New Stereo Soundbook (2nd ed.) by Streicher and Everest?  If so, do you recommend it?

Thanks.

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I have read statements on ramps to the effect that producers insist that stereo recordings of ambient sound be done XY or MS to ensure mono compatibility because large numbers of people still own mono television sets.  A few questions:

Does this mean that nobody recording ambient sound for movies or television uses ORTF? (In these same ramps discussions, I have seen suggestions that ORTF is used, and that in the real as distinct from theoretical world, it works.)

Effects, including ambiences, are in fact recorded some times utilzing the ORTF principles developed and used extensively by French radio broadcasters, but it is not common. The mono compatibility issues come into play not so much in how these sound are recorded but how they are mixed in with all of the rest of the elements with consideration for the final product. All media forms, including filmed movies, video, radio shows, music CDs, DVD Audio and so forth may have several differenrt mixes, or mixdowns, and it is no longer just a simple stereo-mono compatibility issue. The stereo-mono compatibility issue mentioned here may relate to another ongoing discussion which is the recording of stereo dialog or stereo ambiences (by any one of several methods) and what "problems" that may create for others having to complete the soundtrack.

I will ask around my sound effects friends and see if I can get a more detailed answer as to whether there are some compelling reasons to stick with the more widespread techniques of X-Y and MS.

I have posted 2 images, for those who are unfamiliar, with a basic ORTF mic setup.

This technique was adopted by French Radio and uses two cardioid microphones spaced by 17cm (roughly the same as ear spacing) and angled outwards at 110 degrees.  This fine technique often gives a greater sense of space than coincident techniques due to the microphones being ear spaced and thus capturing phase information as well as intensity information.

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Having never used ORTF, my opinion may seem unqualified. 

For stereo efx I use M/S.  (schoeps MK41 and figure of eight).  If I know for sure that the post process can deal properly with mid-side then I submit the tracks in their un-decoded state so that post can have control over the stereo width.  On a job last week where I had little confidence in the editors ability to decode M/S, I decoded the mics into XY before I sent them to my recorder.

Even though ORTF has a following, due to theoretical concern about out of phase signals I prefer a coincident pair or a M/S to ORTF placement. If you have control of your mix, then I recommend M/S. 

M/S is a good technique for small setup such as documentary sfx.  Today’s shoots are sometimes more complex.  In last week’s shoot with the stereo schoeps, those tracks are iso recorded for audience ambience, but must be mixed with the other tracks (also iso tracks) of the singer’s mic, the guitar mic, and several RF lavs on actors.  So the phase integrity gets a bit dicey.

I have a rycote system for schoeps M/S that I no longer use and should probably sell.  I prefer my DPA windpac for M/S.

David Terry

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Around here we generally do not use MS very much for two reasons.  First, it is a hassle to have MS recordings in a SFX library in which all the rest of the fx are normal (XY) stereo--when in a rush one can overlook the MS notations.  Virtually all commercial SFX libraries are made available only in regular stereo.  In order to cut in an MS effect I would have to decode it to stereo, another step, or put it on it's own pair of tracks and decode it @ the mix.  2nd, I am not ever thrilled with the stereo imaging--it always sounds very monoish to me until you end up with a hole in the middle.  For music, especially, I very much like ORTF, and base most of my recording around that method.  For location SFX recording it is kind of a hassle to "package" an ORTF pair for wind protection--in that case XY stereo works better.  I've never visited the BBC mixing rooms, I'd love to see how they handle MS recordings, esp. archiving and cutting.

Philip Perkins

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I have a rycote system for schoeps M/S that I no longer use and should probably sell.  I prefer my DPA windpac for M/S.

David Terry

David - I might be interested in this.  Could you provide more info: model type etc.  feel free to contact me off list

gregsextro at hotmail dot com

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I will ask around my sound effects friends and see if I can get a more detailed answer as to whether there are some compelling reasons to stick with the more widespread techniques of X-Y and MS.

I think that that would be very interesting.

There are people on ramps who have said pretty unequivocably that there is a problem using ORTF for reasons relating to some necessity about producing, for television (which must include all films that may be shown on television), a monaural track due to the fact that people own televisions that produce monaural sound.

I really don't understand why monaural compatibility, which is said to favour XY and MS, is an issue.   I am pretty sure that I have listened, through a monaural radio receiver, to a lot of LPs and CDs that were recorded in stereo.  No doubt some of these recordings were done using ORTF, and probably even AB, and I don't recall being conscious of some deficiency in the sound.  So I don't understand why it should be different if one is receiving through a television.

I figure that I must be missing something, and I'd be grateful to know what it is, because I'm interested in the idea that ORTF might give a greater sense of space.

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Here is a link to a page done by SHURE (extract from a lengthy publication) which talks about stereo mic technique. There is some useful, though somewhat general information, about X-Y, A/B, MS and ORTF. As I said earlier, I do not think "mono compatibility" is the same issue it used to be when stereo recordings first came in or even when stereo TV broadcasts began, because most of these incompatibilities (necessity to provide pure mono for car radios and ancient televisions) are dealt with in some fashion in the mix for release format. As a simple example, the majority of material that is broadcast goes through any one of several major Dolby processors, all of them designed to deal with these issues and to provide a viable release format with high compatibility.

http://www.prosoundweb.com/studyhall/shure/mics/stereo/techniques.php

Regards,  Jeff Wexler

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I think ORTF is a strange format for TV post to work with. XY and MS are most likely more familiar for them and fits into their setups easier.

Many shows are finished in stereo and the major networks do broadcast stereo but not all cable outlets broadcast in stereo. The Bravo channel is one of them.

Eric

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I think ORTF is a strange format for TV post to work with. XY and MS are most likely more familiar for them and fits into their setups easier.

Many shows are finished in stereo and the major networks do broadcast stereo but not all cable outlets broadcast in stereo. The Bravo channel is one of them.

Eric

ORTF isn't strange for post--when we get a stereo audio clip we have no idea how it was recorded, it's just some form of stereo as far as we know.  I can tell right away if the source is MS and I'm listening to it through a stereo patch, and I know I'll have to stop and do a work around to get the MS clip into a form I can use.    All stereo shows have to be mono compatible, but that isn't really such a big deal regarding stereo SFX or ambiances.  When it is a problem it usually has to do with extreme signal processing or mixing errors in the music.

Philip Perkins

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I was at Posthorn Recordings yesterday to buy an audio recorder and I got into a discussion about this issue with Jerry Bruck.  He had just finished doing the sound for a film/sound recording of a performance of Mahler's 2nd Symphony, reviewed in yesterday's New York Times, and he spoke very favourably about using the Radio France system, rather than XY or MS, for ambient stereo recording.  He said that a transition to mono, if necessary, will cost a bit of high frequency, but that the cost will be worth the extra sense of space.  Between the comments of others in this thread, and his comments, I think that I'm going to have a go at ORTF.  Thanks to all.

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I was at Posthorn Recordings yesterday to buy an audio recorder and I got into a discussion about this issue with Jerry Bruck.  He had just finished doing the sound for a film/sound recording of a performance of Mahler's 2nd Symphony, reviewed in yesterday's New York Times, and he spoke very favourably about using the Radio France system, rather than XY or MS, for ambient stereo recording.  He said that a transition to mono, if necessary, will cost a bit of high frequency, but that the cost will be worth the extra sense of space.  Between the comments of others in this thread, and his comments, I think that I'm going to have a go at ORTF.  Thanks to all.

If you are recording music, experiment as much as you can w/ mic placement.  I have, and pretty much all my concert recording setups are now based around a central ORTF pair.

Philip Perkins

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Warning:  This post is going to try the patience of anyone who has little patience for DIY.

I've been thinking about how to set up an ORTF configuration outdoors to record wild sound.  It isn't a problem in light wind.  For stronger wind, I'll need some kind of zeppelin rig.  There are references on the net to nature recordists who use ORTF, but I haven't been able to find information about what they do in zeppelin conditions.  I don't think that any of the commercial zeppelins will fit, or comfortably fit, two cmc541 microphones in an ORTF configuration on a bar (see JW's photo earlier in this thread).  I want to try making a zeppelin that will fit over the microphones and the bar. Presumably, it could be in the shape of a ball.  That may even be preferable (are zeppelins the shape of a zeppelin for acoustic reasons or for convenience/size?)  I was thinking of making a wire frame around a styrofoam core and then cutting out, or melting, the styrofoam.  I'm looking for any suggestions for alternatives for the frame, and any suggestions on what to cover the frame with.

Thanks.

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Guest repete86

Actually, I don't think I would even go for a ball.  I would probably make it in the shape of a shield in order to reduce air resistance. I would think that making it that wide and kind of flat would help and should fit over both mics.

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You could start with a really big zepplin (like the Rycote made for Neumann stereo mics) and have enough room inside

to rig an ORTF pair.  You could also probably fit an ORTF pair using head preamp extension cables like the Schoeps Kat5.

(I used to do this with a Rycote "ball gag" windscreen.)  Otherwise, make your mic mounting and then see how big a cover you need.  I see basketball-sized mic windscreens being used in production stills of "Lawrence of Arabia"-- the issues of lightness and smallness come into play only if you have to be very mobile.  The Rycote "ball gag" is a pretty versitile windscreen, small and not too expensive--I bet you could rig an ORTF pair of capsules inside one with a little custom work.

Philip Perkins

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Ok, maybe this is a little obvious, but what if you set up the mics on the bar like you mentioned and just covered each individual capsule with a baby ball gag ? might even be more practicle for when you want to set up the mics in an A-B or X-Y set up.

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Simon,

I think that you and Philip Perkins have made similar points, which I have now had time to investigate a little.

It turns out that there is a stereo bar on the market that can be mounted in a suspension mount, meaning that the two ORTF mics don't need their own mounts.

The next step is to use, in the case of a Schoeps mic, either a W5D or the basket with fake fur (don't recall the model number but it was recently discussed here, with JW saying that it's a good product and Oleg saying that it is drek - there's nothing like consensus).

So the only problem is when one gets into high wind/Zeppelin territory, for which there does not appear to be any commercially available product that will handle two mics in ORTF configuration.

So how big a problem is this?

A few days ago, while in my favourite pub in New York, I watched a camera crew walk by.  What I mostly noticed was that the camera guy was carrying a fairly diminutive video camera and the sound guy looked like he was dressed for Hallowe'en. Chest harness with a boom pole anchored to it, topped by this huge Rycote Zepellin with furry. The wind was about 5mph.

As a neophyte with this stuff, I'm beginning to think that there is a lot of windscreen overkill going on.

Anyway, I've been experimenting a bit and I'm beginning to think that I can do the ambience recordings that I want to do with windscreens short of a Zepellin.

If not, a New York sound guy told me the other day that a bird cage mounted over ORTF mics makes a great frame :)

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As a neophyte with this stuff, I'm beginning to think that there is a lot of windscreen overkill going on.

....a sudden and unexpected gust of wind is headed your way, and you'll be cabled in and far from your cases..... 

That guy you saw was ready for any reasonable amount of wind.  In the city, especially, you can be in absolute calm and then turn a corner into a stiff wind off the water etc.  that a "softie" style windscreen will not protect you against.  Better to be prepared.

Philip Perkins

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