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#1
Posted to rec.audio.pro
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Quick question ORTF mic angles
If the image seems too wide, in that actors go towards the edges too
easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. Listening to the playback it sounds pretty good, with both mechanical and electrical noise from the lights on the bar not noticeable. We've had to move a couple of lights closer to the mics to get the right lighting effect so we'll see. They made lovely clanking noises after last night when things cooled down. Thanks - Richard -- _/_/_/ _/_/_/ _/_/_/ Richard Corfield _/ _/ _/ _/ _/_/ _/ _/ Time is a one way street, _/ _/ _/_/ _/_/_/ except in the Twilight Zone |
#2
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Quick question ORTF mic angles
On Mon, 11 Feb 2008 08:17:52 GMT, Richard Corfield
wrote: If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. Listening to the playback it sounds pretty good, with both mechanical and electrical noise from the lights on the bar not noticeable. We've had to move a couple of lights closer to the mics to get the right lighting effect so we'll see. They made lovely clanking noises after last night when things cooled down. Move them in - every time! You will find that you still get a perfectly good image at +/- 30 deg. And the best thing is that actors at centre stage aren't working so far off the mic axis, and they will be reproduced better. Most of the problem you are experiencing is to do with the highs - particularly sibilants. When you move even a little way off the axis of one mic, you are getting better centred on the other, and the top end response lifts dis proportionately. If you have the option available, always the smallest diameter mics possible for ORTF, because they will have the best off-axis response - which will give you the best image. d -- Pearce Consulting http://www.pearce.uk.com |
#3
Posted to rec.audio.pro
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Quick question ORTF mic angles
On 2008-02-11, Don Pearce wrote:
If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. Listening to the playback it sounds pretty good, with both mechanical and electrical noise from the lights on the bar not noticeable. We've had to move a couple of lights closer to the mics to get the right lighting effect so we'll see. They made lovely clanking noises after last night when things cooled down. Move them in - every time! You will find that you still get a perfectly good image at +/- 30 deg. And the best thing is that actors at centre stage aren't working so far off the mic axis, and they will be reproduced better. Most of the problem you are experiencing is to do with the highs - particularly sibilants. When you move even a little way off the axis of one mic, you are getting better centred on the other, and the top end response lifts dis proportionately. If you have the option available, always the smallest diameter mics possible for ORTF, because they will have the best off-axis response - which will give you the best image. Thanks. It's dress rehearsal tonight so I can give that a go. The band are far left though so taking them too far off axis could hinder things. The mics are Behringer C2 - cheap but not bad for the price actually. Apparently Behringer fixed the output circuit last year some time so noise isn't such a problem. These are on quite a long cable run. - Richard -- _/_/_/ _/_/_/ _/_/_/ Richard Corfield _/ _/ _/ _/ _/_/ _/ _/ Time is a one way street, _/ _/ _/_/ _/_/_/ except in the Twilight Zone |
#4
Posted to rec.audio.pro
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Quick question ORTF mic angles
On Mon, 11 Feb 2008 10:14:25 GMT, Richard Corfield
wrote: On 2008-02-11, Don Pearce wrote: If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. Listening to the playback it sounds pretty good, with both mechanical and electrical noise from the lights on the bar not noticeable. We've had to move a couple of lights closer to the mics to get the right lighting effect so we'll see. They made lovely clanking noises after last night when things cooled down. Move them in - every time! You will find that you still get a perfectly good image at +/- 30 deg. And the best thing is that actors at centre stage aren't working so far off the mic axis, and they will be reproduced better. Most of the problem you are experiencing is to do with the highs - particularly sibilants. When you move even a little way off the axis of one mic, you are getting better centred on the other, and the top end response lifts dis proportionately. If you have the option available, always the smallest diameter mics possible for ORTF, because they will have the best off-axis response - which will give you the best image. Thanks. It's dress rehearsal tonight so I can give that a go. The band are far left though so taking them too far off axis could hinder things. The mics are Behringer C2 - cheap but not bad for the price actually. Apparently Behringer fixed the output circuit last year some time so noise isn't such a problem. These are on quite a long cable run. - Richard Ah - the band could be a problem. If they aren't too big, could you perhaps spot mic them with a third mic and pan it in hard left. Start with it at zero level, and bring it up just far enough to add a little clarity to the music, just don't try and make it the main source of band sound. d -- Pearce Consulting http://www.pearce.uk.com |
#5
Posted to rec.audio.pro
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Quick question ORTF mic angles
"Richard Corfield" wrote in
message nal.littondale.dyndns.org If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. You've missed the whole point of microphone placement - you are supposed to discover that by trying different angles and listening! You also need to learn how to compensate for suboptimal angles during editing and mixing. |
#6
Posted to rec.audio.pro
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Quick question ORTF mic angles
On Feb 11, 3:17 am, Richard Corfield
wrote: If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? The simple answer is that there is only one "official" ORTF configuration. Cardioid microphones at an included angle of 110 degrees, positioned so that at this angle, the capsules are 17 centimeters apart. Anything else and it is no longer ORTF. You are supposed to place the mics so that you capture what you want. Knowing that this is not always possible, you just listen while moving the mics until you get the coverage and stereo field that you want. Be sure to check the sound when left and right channels are combined to mono to be sure that nothing important drops out. |
#7
Posted to rec.audio.pro
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Quick question ORTF mic angles
On 2008-02-11, Soundhaspriority wrote:
Richard, Here's a classic article on the subject: http://www.microphone-data.com/pdfs/Stereo%20zoom.pdf Thanks. I've printed that off and will have a good read. - Richard -- _/_/_/ _/_/_/ _/_/_/ Richard Corfield _/ _/ _/ _/ _/_/ _/ _/ Time is a one way street, _/ _/ _/_/ _/_/_/ except in the Twilight Zone |
#8
Posted to rec.audio.pro
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Quick question ORTF mic angles
"Richard Corfield" wrote in message nal.littondale.dyndns.org... If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. You don't mention the capsul-to-capsul distance. In any case, if you have too much at the outer extents of the image then you want to either a) angle the mics inwards, and/or b) maintain your current angle but bring the mics closer together |
#9
Posted to rec.audio.pro
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Quick question ORTF mic angles
Richard Corfield wrote:
If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle,... When the rush is over, go to your library and read: "Two-Channel Stereophonic Sound Systems" by F.H. Brittain and D.M. Leakey. Wireless World. Vol 62 (May 1956) pp.206 - 210 Their experiments were done with panned mono and a classic Blumlein array, but the results show that a lot of the image posititoning problems are not caused by the mic set-up but are actually inherent in the two-loudspeaker playback arrangement. This raises the old question of whether the recording engineer should distort his recording in order to compensate for the defects of the reproducing suystem. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#10
Posted to rec.audio.pro
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Quick question ORTF mic angles
On Mon, 11 Feb 2008 08:17:52 GMT, Richard Corfield
wrote: If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? My guess narrower. I'm at about +-45deg at the moment on a bar just forward of the stage so quite close to the action. It means that the angular size of the action is somewhere around 130deg. Listening to the playback it sounds pretty good, with both mechanical and electrical noise from the lights on the bar not noticeable. We've had to move a couple of lights closer to the mics to get the right lighting effect so we'll see. They made lovely clanking noises after last night when things cooled down. Thanks - Richard Richard, I've just remembered a technique I saw used an awful long time ago when the BBC were recording a stage drama. They used three mics in a sort of ORTF plus one in the middle (a bit like a Decca Tree, but co-located). That allowed them to put the two side mics pointed at at quite a wide angle - about 150 degrees total I think. The centre mic pointed straight forwards. They were then mixed with the side mics panned hard left and right, and the centre mic panned to centre. This resulted in a very natural spread of images, with good tone balance all the way across. Worth a try, I think if you can get hold of a third mic. d -- Pearce Consulting http://www.pearce.uk.com |
#11
Posted to rec.audio.pro
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Quick question ORTF mic angles
On 2008-02-12, Adrian Tuddenham wrote:
When the rush is over, go to your library and read: "Two-Channel Stereophonic Sound Systems" by F.H. Brittain and D.M. Leakey. Wireless World. Vol 62 (May 1956) pp.206 - 210 Their experiments were done with panned mono and a classic Blumlein array, but the results show that a lot of the image posititoning problems are not caused by the mic set-up but are actually inherent in the two-loudspeaker playback arrangement. It sounds interesting. I used to have a lovely pink book about recording techniques which I left at the theatre once and didn't find again. This raises the old question of whether the recording engineer should distort his recording in order to compensate for the defects of the reproducing suystem. I think in this case I ought to as the purpose of the recording is to be listened to rather than to capture a perfect copy of the event. I'm going to have to try to arrange a spot mic for the band, or take some of their mix on the PA into the recording, though that adds some monitoring black magic balancing it. I don't have a multitrack recorder or outside broadcast lorry. The mics are almost over the stage, so the singers are a lot closer to them than the musicians. (I'm also running around like a headless chicken as we failed to secure our followspot operator before last rehearsal so we have two operators running between three things. A pain already in rehearsal as I've wanted to change the band mix but been followspotting at the time. In production starting tonight I'll run both lighting and sound during musical numbers as both desks are in proximity. My lighting operator prefers manual mode using group memories over sequence mode - more control, and maybe not as boring as pressing "Next". Programming in a sequence could be risky at this late stage - a bit like blind plotting which I've seen some people do.) - Richard -- _/_/_/ _/_/_/ _/_/_/ Richard Corfield _/ _/ _/ _/ _/_/ _/ _/ Time is a one way street, _/ _/ _/_/ _/_/_/ except in the Twilight Zone |
#12
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Quick question ORTF mic angles
Richard Corfield wrote:
(I'm also running around like a headless chicken as we failed to secure our followspot operator before last rehearsal... Brings back memories of operating follow-spots from the top of a swaying scaffolding tower which was partly roped together from bits of two different tower systems. I was sitting on a plank, directing one spot with each hand and operating a pair of slate dimmers (screwed to a plank a little further down) with my bare feet. I wore a pair of gardening gloves because the lanterns were hot, so it didn't matter that the 240v supply didn't have an earth connection. Ahh... Happy days before risk-assessments were mandatory. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
#13
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Quick question ORTF mic angles
On 2008-02-13, Adrian Tuddenham wrote:
Brings back memories of operating follow-spots from the top of a swaying scaffolding tower which was partly roped together from bits of two different tower systems. I was sitting on a plank, directing one spot with each hand and operating a pair of slate dimmers (screwed to a plank a little further down) with my bare feet. I wore a pair of gardening gloves because the lanterns were hot, so it didn't matter that the 240v supply didn't have an earth connection. Ahh... Happy days before risk-assessments were mandatory. Some of the rigging I've been doing this weekend wouldn't be allowed. We did as much as possible with the bar lowered, but some things like focusing and moving some lights around a little we did with the bar in place. I think I should theoretically have had a harness, but instead did the normal perch on top of step ladders with someone at the bottom and hold onto the bar when I was high. A lot of the focusing had feet below 2 meters so I think that is within the limit for working without harness. Back in my theatre days we had very big step ladders on stage, and very big ordinary ladders up to the front of house bars which were secure enough to rest the ladders against them. Our lighting director once had the stage step ladders go over on him and was saved when the top tangled in a safety chain. It shows how strong those safety chains are. - Richard -- _/_/_/ _/_/_/ _/_/_/ Richard Corfield _/ _/ _/ _/ _/_/ _/ _/ Time is a one way street, _/ _/ _/_/ _/_/_/ except in the Twilight Zone |
#14
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Quick question ORTF mic angles
Mike Rivers wrote:
On Feb 11, 3:17 am, Richard Corfield wrote: If the image seems too wide, in that actors go towards the edges too easily rather than stay in the middle, do I need to make the microphones wider angled or narrower? The simple answer is that there is only one "official" ORTF configuration. Cardioid microphones at an included angle of 110 degrees, positioned so that at this angle, the capsules are 17 centimeters apart. Anything else and it is no longer ORTF. You are supposed to place the mics so that you capture what you want. I think if you are going to go hard-core official ORTF, you want to use whatever types of mics they were using too! All these mic'ing techniques are starting points, really. ORTF, XY, AB etc. Once you set them up, it's worth adjusting them to the situation and mics. Change the angle, the distance apart, the height, distance to source. Listen for how each change effects the sound---in a number of ways. Knowing that this is not always possible, you just listen while moving the mics until you get the coverage and stereo field that you want. Be sure to check the sound when left and right channels are combined to mono to be sure that nothing important drops out. Absolutely good advice. Rob R. |
#15
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Quick question ORTF mic angles
On Feb 17, 11:55 am, Rob Reedijk wrote:
I think if you are going to go hard-core official ORTF, you want to use whatever types of mics they were using too! I suppose so, at least use true (textbook-pattern) cardioids, which I think was what was used in the textbook configuration, Probably some Schoepes or other. ORTF is just one of the infinite number of "near coincident" stereo mic setups, but it's one that has a definition. If I'm not mistaken, "X-Y" is defined as two cardioids at 90 degrees, but with modern mics, it's more often better implemented with two hypercardioids at 110 degrees. All these mic'ing techniques are starting points, really. Sure, but by adhering to a standard and making it work (by adjusting non-specified parameters distance and height), you can more easily repeat the technique should you need to do so. |
#16
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Quick question ORTF mic angles
Mike Rivers wrote:
On Feb 17, 11:55 am, Rob Reedijk wrote: I think if you are going to go hard-core official ORTF, you want to use whatever types of mics they were using too! I suppose so, at least use true (textbook-pattern) cardioids, which I think was what was used in the textbook configuration, Probably some Schoepes or other. Doesn't matter, as long as it has a conventional medium cardioid pattern and is flat off-axis sort-of. One of the wonderful things about ORTF is that it does not rely on aberrations of particular microphone designs, like the Decca Tree for instance. It will work nicely with a wide variety of microphones. ORTF is just one of the infinite number of "near coincident" stereo mic setups, but it's one that has a definition. There are several of these, including NOS, which have names. ORTF, though, is a good starting point for most environments. If I'm not mistaken, "X-Y" is defined as two cardioids at 90 degrees, but with modern mics, it's more often better implemented with two hypercardioids at 110 degrees. It's not really X-Y any more, though, because it has a rear lobe. It's something different. Yes, it's something that probably sounds better because typical modern hypercardioids are better off-axis than typical modern cardioids, but it's not the same. All these mic'ing techniques are starting points, really. Sure, but by adhering to a standard and making it work (by adjusting non-specified parameters distance and height), you can more easily repeat the technique should you need to do so. Which is why there are calibrated stereo bars. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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