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I have been thinking a lot about the heigh of microphones Condenser Microphones
Old 9th July 2018
  #1
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Thomas W. Bethe's Avatar
I have been thinking a lot about the heigh of microphones

I have been doing a lot of thinking lately about the height of microphones when recording classical music in an auditorium. When I worked for the college we used flown microphones for almost all the concert recordings. (Neumann SM-69 and AKG C426Bs using both M-S and X-Y configs). I got some amazing recordings using those microphones. They were about 10 feet high off the stage and back about 4 to 6 feet from the stage lip. The sound was good and the imaging was also good. When I started into doing my own recordings I went with stand microphones (X-Y or ORTF) about 4 to 6 feet above the conductors head and 6 to 10 feel in front of the stage. I also got good recordings from that setup. Lately I have been doing a lot of thinking about how the ear perceives the sound field. In most auditoriums the majority of the audience is sitting below the orchestra. We hear just fine and even the instruments in the back of the orchestra are heard well and in good balance. I think the next concert I record I am gong to try one set of microphones at audience ear level into a seperate recorder and see what happens.

Any thoughts on mic height for the main microphones? Thanks in advance.
Old 9th July 2018
  #2
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I think that "how the ear perceives the sound field", along with all the perceptual processing that goes with human hearing, is very different from how the microphone captures the sound field. I have always thought of the microphone as 'the innocent ear', free of human bias such as visual correlation, preconceptions, and generally 'intellectual' listening (i.e. the way we can focus in on an instrument in a sound field because we know its there from a score or watching a YouTube video and are then able to locate it spatially in the sound field). So the magic happens when sound of 'the innocent ear' comes out of the speakers and paints a picture of the performance in the mind's eye (ear?). By elevating the microphones to more of a bird's eye (bird's ear?) vantage point, the individual components of the orchestra are captured in a way that makes the playback seem more realistic when the listener does not benefit from visual perceptions to add spatial cues. This conceit means that the 'best seat in the house' for a listener is not necessarily the best place for the microphone capture. Well, that's my theory, which is just a theory...

Last edited by jimjazzdad; 9th July 2018 at 03:26 PM.. Reason: clarity
Old 9th July 2018
  #3
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Brent Hahn's Avatar
 

Two things.

1. People are noisy. Al other things being equal, I like to minimize my people:music ratio.

2. This is based on experience that's probably very limited compared to yours, but... when I've recording rehearsals with an empty house as well as the concert performance, with designs on whacking together a CD from them, the takes were a better match with flown mics than with lower ones. Y'all who have done lots of this may feel the opposite, and my observations are based on several gigs but in only a couple of different halls.
Old 9th July 2018
  #4
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Bruce Watson's Avatar
 

Quote:
Originally Posted by Thomas W. Bethe View Post
Lately I have been doing a lot of thinking about how the ear perceives the sound field. In most auditoriums the majority of the audience is sitting below the orchestra. We hear just fine and even the instruments in the back of the orchestra are heard well and in good balance. I think the next concert I record I am gong to try one set of microphones at audience ear level into a seperate recorder and see what happens.
The human ear/hearing system is not a microphone, or a pair of microphones, or a surround set of microphones. Far from it.

As to concert seating, much of what you hear in a concert setting is what you see. That is, you see on the stage where the musicians are sitting, so that's the spread and location of what you hear. The visual system fills in the blanks and supports the fuzzy localization of the actual sound. Have you ever noticed that you can watch just one of the musicians to the point that you can hear what she is playing above the others? Do you think a microphone can do that?

Anyway, try your experiment. You won't be the first to try it, nor the last. Tell us what you think of your results. These kinds of experiments are always fun.
Old 9th July 2018
  #5
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tourtelot's Avatar
The problem with experimenting is, for me, that if the experiment fails, the client is unhappy. It's hard to try out a new pair or technique or height adjustment or front-to-back etc during a paid recording.

Sometimes, I'll put up a new/different pair on the same stand/bar to compare but almost always go with what I know. It's a bit of a shame since no new earth-shattering techniques are ever discovered through doing the same old thing.

D.
Old 9th July 2018
  #6
I approach this all with a healthy schizophrenia, and I diagnose the situation somewhat like thusly:

These poor saps in attendance are getting the worst version of what's being presented here, the live, unalloyed version: from one single seat on the floor (or the balcony), at the mercy of a generally merciless reality. It takes a great leap of the imagination for them to loose themselves in this music, and make the best of it-- absorbing the visuals and ignoring the anomalies or distractions. Because, after all, there is a thrill to be had in watching something unfold before your eyes, and being there.

I'm there for a totally different reason. I'm there as a stand-in for Plato: to capture the form of this whatever-it-is-they're doing. That's why I will prefer mics hovering over the group like birds of prey, or surrounding them like hungry wolves. My contract is to agree to produce something later, that will play out of loudspeakers, designed to convey a distilled essence of it, with *hopefully* a clarity and focus that kind of defy reality and real life-- with all trickery and every fraud available to me, I want to create an experience for the listener that slips these surly bonds, that isn't this one single performance anymore.

Uh... what was the question?
Old 9th July 2018
  #7
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much of my work for orchestras includes both live mixing and recording at the same time, often in fairly unusual places, sometimes with multichannel/surround reproduction, so i have to bring quite a lot of gear anyway (desk, fiber to connect the stagebox, multichannel amp, frontfills, measuring mic/analyzer/speaker processor etc. in addition to the usual equipment) almost always.

bad thing: i'm often forced into putting mics in places i would not necessarily choose for recording in unamplified situations yet have to deliver mixes that do not exhibit any technical shortcomings.

good things: it's not much of an issue to put up another pair/array of mics so i get to experiment a lot.
i'm much more comfortable with less than ideal mic characteristics, positions and room sound ever since - as long as i have enough dsp/gear to compensate!
and from using pa's, i'm much more aware of how sound bounces off surfaces/areas depending on density/temperature and humidity so i'm trying to adjust my mic placements in the same way as i would adjust the height/angles of a pa.

i was never a big fan of mics way up in the air - these days, i mostly go even lower than 30 years ago (and from what i get to see in pics/videos from other engineers).

---

i once got to set up a soundfield mic at the conductor's position during rehearsals: wish i could always do this and that mixes from the conductor's perspective could get released (and be in surround!) rather than in a more traditional way which imo is from the perspective of an listener sitting somewhere between row 5 and 15 - would i consider this to be ideal, i'd try to put my mics there...
Old 9th July 2018
  #8
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tourtelot's Avatar
Quote:
Originally Posted by deedeeyeah View Post
would i consider this to be ideal, i'd try to put my mics there...
Overwhelmed by first strings. Not for me.

I once had a conductor listen to a recording engineered by a famous live classical recordist as he played back a bit of the day's work. "Not enough strings" says the conductor. Sounded perfectly balanced to us but then, we had not spent the whole afternoon standing five feet away from 30 first strings.

D.
Old 9th July 2018
  #9
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Quote:
Originally Posted by tourtelot View Post
Overwhelmed by first strings. Not for me.

I once had a conductor listen to a recording engineered by a famous live classical recordist as he played back a bit of the day's work. "Not enough strings" says the conductor. Sounded perfectly balanced to us but then, we had not spent the whole afternoon standing five feet away from 30 first strings.

D.

maybe i was lucky that the composition they were rehearsing was not that heavy on strings (and using a soundfield can help to keep things under control while mixing.)
Old 10th July 2018
  #10
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Brent Hahn's Avatar
 

Quote:
Originally Posted by tourtelot View Post
Sounded perfectly balanced to us but then, we had not spent the whole afternoon standing five feet away from 30 first strings.
I remember first hearing a record of the Mozart Requiem after only having heard it from amid the bass section of a huge college choir and thinking, "No sh!t!"
Old 10th July 2018
  #11
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hbphotoav's Avatar
 

Quote:
Originally Posted by joelpatterson View Post
Uh... what was the question?
Exactly.

HB

*Right there with you...
Old 10th July 2018
  #12
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Thomas W. Bethe's Avatar
When I do my "experiment" it will go to a different recorder and will NOT be what the client is given (unless it sounds soooooooooo much better).

I agree with all who say your ears are a lot different from microphones. I use to teach that as part of a course on orchestral miking that I taught a long time ago. I would give students some virtual microphones and ask them to put them in the hall at a place were they thought the sound would be best. Most of them put them near the conductor's head. A couple of times I would let them roam around rehearsals with a Tascam DR100 MKII and using only the built in microphones and a pair of headphones let them determine where the sound was the best with out resorting to large microphone stands. Some came up with some innovative ideas some copped out and just put the Tascam on a music stand in the first row of the venue.

Not sure when the next time I will get a chance to record a full orchestra but I am looking forward to some experimenting.

Thanks for all the GREAT replies.
Old 10th July 2018
  #13
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some clue to how much 'departure from conventional miking wisdom' is possible yet still able to render a credible (if not optimal) recording....would be the example of PZM-type boundary-layer mics placed on the floor in front of an opera performance. This is often done when either wireless lavalier or conventional stand miking is impossible...and ensures relative microphone invisibility.

I'm not saying it's ideal...or not moderately or even severely compromised...but yet it persists as 'a method'
Old 10th July 2018
  #14
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Peter Allison's Avatar
I have said this kind of thing before, regarding "pipe organs". the general consensus among most "pro recording outfits", is to get the mic(s) as high as possible, to soften floor reflections? BUT the builders all over the world, voice there instruments at ground level. I have personally never gone higher than 6 feet ( after asking a professional record label in the UK) and used PZM's even, with good results, as my sound bites on here, have confirmed (some may have heard the very "amateur" results)
Old 10th July 2018
  #15
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2 reasons why putting mics in the audience doesn’t
work for audio recording:
1. It is my understanding that what we see actually affects brain processing of what we hear.
Obviously this is an issue for listening to audio-
only recordings.
2. Our ability to hear a given sound source is partly based on our ability to exclude unwanted background sounds(reverberance + extraneous sounds) and especially the further we are from a sound source.
Given that none of our mic techniques (and reproduction techniques) can totally/realistically reproduce all the ambient sound information that hits our ears it is reasonable to think that our brain’s ability to exclude unwanted ambient sounds ( and focus) on the desired sound will be compromised, and especially in the audience position where the direct to reverberant(plus extraneous ) sound ratio is so much lower.

Perhaps the least compromised recording+
reproduction system in this regard would be a binaural recording made with mics in our own ears (or exact replica) of our own head and torso
and listened back over highly accurate headphones while watching immersive video but any changes ( recording with someone else’s head/torso, speaker playback instead of headphones, no video) would degrade the perceived sound quality ( esp the ability
to hear the desired direct to ambient balance) from the real experience.

Because of the above issues, we have to place our mics much closer ( higher direct to reverberant ratio position) in order to compensate for the reduced sound (and visual) information we have available to us to focus on the desired sound source and exclude/reduce background sound (ambience/reverberance + extraneous sounds).

Last edited by Folkie; 10th July 2018 at 03:21 PM.. Reason: grammar
Old 10th July 2018
  #16
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My pianist wife and I have subscribed the Nashville Symphony for going on 35 years (since 1984) and, especially in Schermerhorn Symphony Center (purpose-built for NSO and Chorus a decade ago) we choose seats in the front of the center balcony (at the end of main floor, above the "Founders Circle" seats, usually 3rd or 4th row) where we have a view of every instrument on the stage. While this is too far back for mics placement, everything onstage is clearly audible, and in balance. In a typical setup, high strings to the left and center; perc left/center; horns/reeds in the center; low strings center/right; trumpets and trombones center right; basses and tuba hard right. When we occasionally end up in orchestra level seats, we remark how, though the soloists are a bit more "pronounced"... the balance of the orchestra is not as nice, nor the "detail" as detectable.

One outcome of that experience is that I try to place my main mics (usually pairs of Gefell M296 in AB and MKH8040 in ORTF or NOS) so as to ensure that they are high enough and close enough to be able to "see" all the instruments onstage... i.e., 4-6' above the conductor's head from 3-10' back, depending on the width of the stage. Tall stands are necessary, of course. Finding the "best" height/depth is, with enough time (most of my work is at concert, not sessions), the trick... and rarely does the array go lower than the initial visual assessment.

FWIW, NSO onsite live recordings (for local broadcast and, occasionally, for release projects... if the requisite cough-ers and sneezers allow) are generally anchored by a pair of omnis (Schoeps or Earthworks, IIRC) flown on fishline at 5' or so over the top of the conductor's head, and 4-6' behind the podium... supplemented by omni outriggers on the same guy wire, and spots on stands as needed.

One old guy's opinion... worth every penny paid.

HB
Old 10th July 2018
  #17
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Quote:
Originally Posted by hbphotoav View Post
My pianist wife and I have subscribed the Nashville Symphony for going on 35 years (since 1984) and, especially in Schermerhorn Symphony Center (purpose-built for NSO and Chorus a decade ago) we choose seats in the front of the center balcony (at the end of main floor, above the "Founders Circle" seats, usually 3rd or 4th row) where we have a view of every instrument on the stage. While this is too far back for mics placement, everything onstage is clearly audible, and in balance. In a typical setup, high strings to the left and center; perc left/center; horns/reeds in the center; low strings center/right; trumpets and trombones center right; basses and tuba hard right. When we occasionally end up in orchestra level seats, we remark how, though the soloists are a bit more "pronounced"... the balance of the orchestra is not as nice, nor the "detail" as detectable.

One outcome of that experience is that I try to place my main mics (usually pairs of Gefell M296 in AB and MKH8040 in ORTF or NOS) so as to ensure that they are high enough and close enough to be able to "see" all the instruments onstage... i.e., 4-6' above the conductor's head from 3-10' back, depending on the width of the stage. Tall stands are necessary, of course. Finding the "best" height/depth is, with enough time (most of my work is at concert, not sessions), the trick... and rarely does the array go lower than the initial visual assessment.

FWIW, NSO onsite live recordings (for local broadcast and, occasionally, for release projects... if the requisite cough-ers and sneezers allow) are generally anchored by a pair of omnis (Schoeps or Earthworks, IIRC) flown on fishline at 5' or so over the top of the conductor's head, and 4-6' behind the podium... supplemented by omni outriggers on the same guy wire, and spots on stands as needed.

One old guy's opinion... worth every penny paid.

HB
Yes,
having our mics able to “see” all the instruments is essential if you want to be able
to hear the full frequency range of all the instruments. If not, then we only get the full frequency range for the instruments in front and just the lower frequencies ( that can diffract around those in front), for the rest.
The mid and high frequencies (not the low frequencies) are what help us to locate sounds and separate them from the reverberant/background-(see my post above).

The other reason to get mics high, besides “seeing”/ hearing the full frequency range of all the instruments, is that it helps to even out the
relative distance (and thus loudness) of the front vs rear instruments.
Old 11th July 2018
  #18
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tourtelot's Avatar
Quote:
Originally Posted by Folkie View Post

The other reason to get mics high, besides “seeing”/ hearing the full frequency range of all the instruments, is that it helps to even out the
relative distance (and thus loudness) of the front vs rear instruments.
Remember though, orchestras are seated to be "front firing," loudest players to the rear please.

Too high gives me too much "room" in the ratio for my taste, which tends toward dryer.

FWIW, I usually start my main pair, for orchestral recordings, let's say omnis, maybe, four feet above the conductor's head and (if it works), maybe, five feet or so downstage. This seems to give me a good balance and duplicates what I have seen for in-house rigs elsewhere where Grammy winning classical album projects are recorded. The "maybes" in the last bit are the killers. The main pair could, on any given day, realistically, end up just about anywhere, alas.

D.
Old 11th July 2018
  #19
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I use a similar go to position for my main pair and I agree that too high is too reverberant and not good. On the other hand too low doesn’t give a good balance of the front and back. As always the problem is to find the sweet spot-something
that is tough to do when there is no rehearsal to
experiment with.

Last edited by Folkie; 11th July 2018 at 02:40 AM.. Reason: add comment
Old 11th July 2018
  #20
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Quote:
Originally Posted by Folkie View Post
2 reasons why putting mics in the audience doesn’t
work for audio recording:
1. It is my understanding that what we see actually affects brain processing of what we hear.
Obviously this is an issue for listening to audio-
only recordings.
2. Our ability to hear a given sound source is partly based on our ability to exclude unwanted background sounds(reverberance + extraneous sounds) and especially the further we are from a sound source.
Given that none of our mic techniques (and reproduction techniques) can totally/realistically reproduce all the ambient sound information that hits our ears it is reasonable to think that our brain’s ability to exclude unwanted ambient sounds ( and focus) on the desired sound will be compromised, and especially in the audience position where the direct to reverberant(plus extraneous ) sound ratio is so much lower.

Perhaps the least compromised recording+
reproduction system in this regard would be a binaural recording made with mics in our own ears (or exact replica) of our own head and torso
and listened back over highly accurate headphones while watching immersive video but any changes ( recording with someone else’s head/torso, speaker playback instead of headphones, no video) would degrade the perceived sound quality ( esp the ability
to hear the desired direct to ambient balance) from the real experience.

Because of the above issues, we have to place our mics much closer ( higher direct to reverberant ratio position) in order to compensate for the reduced sound (and visual) information we have available to us to focus on the desired sound source and exclude/reduce background sound (ambience/reverberance + extraneous sounds).
Good points about the ear/brain interface processing (and the involvement of the visuals to 'fill in the missing information') If it were down to the physiology of the outer ear- ear canal and torso alone, then dummy head binaural should be able to be placed anywhere that a seated human reports experiencing good sound in a hall ? Clearly not the case, so it's all that brain processing which saves the day....

Kudos to whichever genius can model that as an algorithm, and apply it as post processing to a recording made in a clearly sub-optimal (for mics) location. Maybe the Fraunhofer Institute folks are already chipping away at this Everest-sized conundrum ?
Old 11th July 2018
  #21
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Dummy Head binaural recording is also compromised by the differences between a standard dummy head/torso/earlobes and that of individual listeners. A lot of us may be dummies but we’re all variably different from standard
recording dummies.
Old 11th July 2018
  #22
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hbphotoav's Avatar
 

Quote:
Originally Posted by tourtelot View Post
... The main pair could, on any given day, realistically, end up just about anywhere, alas. D.
Indeed. That’s what makes it... fun.
Old 11th July 2018
  #23
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John Willett's Avatar
 

Wink

Quote:
Originally Posted by Folkie View Post
Dummy Head binaural recording is also compromised by the differences between a standard dummy head/torso/earlobes and that of individual listeners. A lot of us may be dummies but we’re all variably different from standard
recording dummies.
That's why I use a Schneider disk
Old 14th July 2018
  #24
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roonsbane's Avatar
Keep in mind you are capturing a ratio. The ratio of front to back. The ratio wil be different with aimed directional mics as opposed to omni’s.
Cameron
Old 14th July 2018
  #25
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roonsbane's Avatar
Also the Inverse square law says that as a listener gets farther away from the ensemble, the differences in levels between instrument willl be less and less, but this does not mean mics back in the hall or low will give you what you are wishing to hear.
Cameron
Old 14th July 2018
  #26
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Quote:
Originally Posted by roonsbane View Post
Also the Inverse square law says that as a listener gets farther away from the ensemble, the differences in levels between instrument willl be less and less...
njet: the relationship between instruments doesn't change (much) with increasing dustance, it's the damping of the hf range and the ratio of direct sound versus reflected/refracted/absorbed sound (reverb) that does change - just put up the same mic system at the far end of a hall as you use for the mains, add some hf to the rear system and then compare: you'll get a more blurred image and more 'room sound' but levels between instruments stay pretty much intact!

Last edited by deedeeyeah; 14th July 2018 at 10:57 AM.. Reason: slightly edited for clarification
Old 14th July 2018
  #27
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Quote:
Originally Posted by deedeeyeah View Post
njet: the relationship between instruments doesn't change much, it's the damping of the hf range and the ratio of direct sound versus reflected/refracted/absorbed sound (reverb) that does change.
The inverse square issue has a bearing as well
as the points you make. All are reasons why
it is important to not be too low/ too close to the front of the orchestra with the main pair and esp
with omni’s. Too low/too close to the front exaggerates the differences in level, high frequency content and direct to reverberant ratio.
With more directional mics/patterns( eg Blumlein aimed at the back of the orchestra) the level
and high frequency content differences between front and rear are reduced somewhat.
Old 14th July 2018
  #28
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many favour omnis as main mics, i don't: i'm trying to capture mostly direct sound close to ensembles/orchestras with (close to) coincident cardioid pairs and use omnis only at the rear of halls to record as much diffuse sound as possible - because i want to have the option of changing the relationship between front and back mics in post (or while going on air). also, i mostly don't like the image i'm getting with spaced omnis (and even less with further mics on most arrays) - nothing wrong with that though, it's about taste (and mine is inferior one might say...)
Old 14th July 2018
  #29
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Quote:
Originally Posted by tourtelot View Post
Overwhelmed by first strings. Not for me.

I once had a conductor listen to a recording engineered by a famous live classical recordist as he played back a bit of the day's work. "Not enough strings" says the conductor. Sounded perfectly balanced to us but then, we had not spent the whole afternoon standing five feet away from 30 first strings.

D.
I think this is an important point. I've often heard it repeated that the recording engineer should aim for the balance heard by the conductor. I think this is not necessarily the case. Probably, in the vast majority of cases, the conductor is not hearing the balance as heard in the hall. Much like an engineer learns how to translate what they hear in their headphones to how it will sound through their monitors, so the conductor learns how to translate what they hear on the podium to how it will sound in the hall.

In the orchestra I play in, on the conductors podium, the winds are very soft. This usually throws off visiting conductors and the winds usually speak up to inform the visiting conductor.

The wise conductors understand this and adjust.
Old 14th July 2018
  #30
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Was listening in rehearsal today to Impressionist Debussy and Ravel, at the stage lip, a 10 pc v talented ensemble,perfect on a balmy English summer day
It sounded Wonderfull, wide and fully detailed
But in performance it could be catastrophic
Easier to aim for the birds eye view, away from the unpredictable punters
The stage manager was in overdrive
2 harps ,piano moved on and off and a new soprano flown in after medical problems, a miracle, never seen so many coloured tape marks onstage
Later mouth music from a contemporary female trio and 6 new composers
Tomorrow wind trio ,plus synths and electronic processing /PA and 6 new composers..
Roger
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