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-   -   Soprano distortion (https://www.gearslutz.com/board/remote-possibilities-in-location-recording-amp-production/747181-soprano-distortion.html)

MichaelPatrick 20th July 2012 07:34 AM

Soprano distortion
 
Operatic sopranos can distort in recordings and even in playback on some systems, yet there's very little written in English about this phenomenon that's searchable on the internet. I would love to pick the brain of a skilled Tonmeister who frequently records opera or has experience with critical Soprano recordings.

Leaving out obvious causes like analog and digital clipping, what other causes are there for this particular kind of distortion -- and what can be done to prevent it or fix it in post if the signal appears clean but sounds bad?

David Spearritt 20th July 2012 09:49 AM

Michael,

My partner is an operatic soprano and I have recorded her and many others and have experienced this problem. I have found that the distortion is heard acoustically with the ears as well which points to a distorting effect in the vocal tract.

If you listen to just the recording you would swear that it is distortion in the audio chain. But I think it is at or within the source, depending on the singer. When they push it can be much worse even though the SPL is largely unchanged.

I have also noticed that some phase/comb filter effects come into play when using spaced mics, hence I always use a coincident pair as the vocal spotter.

A very interesting problem and phenomenon. There are some heavyweight academics studying soprano vocal tracts, in the most professional manner of course.
Academic Staff at Physics UNSW: Wolfe

Rolo 46 20th July 2012 10:01 AM

Recorded a powerful Mezzo Soprano last weekend
My normally transparent HD25IIs didnt like her
My HD 650 open backs did
Its not just the voice cracking... it can be the kit.

MichaelPatrick 20th July 2012 04:38 PM

Quote:

Originally Posted by David Spearritt (Post 8086282)
Michael,

My partner is an operatic soprano and I have recorded her and many others and have experienced this problem. I have found that the distortion is heard acoustically with the ears as well which points to a distorting effect in the vocal tract.

If you listen to just the recording you would swear that it is distortion in the audio chain. But I think it is at or within the source, depending on the singer. When they push it can be much worse even though the SPL is largely unchanged.

I have also noticed that some phase/comb filter effects come into play when using spaced mics, hence I always use a coincident pair as the vocal spotter.

A very interesting problem and phenomenon. There are some heavyweight academics studying soprano vocal tracts, in the most professional manner of course.
Academic Staff at Physics UNSW: Wolfe

A paper by the author, Wolfe, says this: "They sang piano (softly) to avoid saturating the microphone and to improve the signal-to-noise ratio."

I don't know his definition of saturation, but I imagine he might mean that sufficient resonance modes in the transducer make it nonlinear with regard to it's designed function, i.e., simple acoustic-to-electric transduction.

rumleymusic 20th July 2012 05:43 PM

I have experienced this as well with soprano and other intense high pitched instruments (like trumpet). Hard to pinpoint the source, though an educated guess would be microphones and other audio gear are tested and designed with the idea that the highest level peaks are in the bass. Not all equipment is capable of withstanding such high db levels in the upper mids. High voltage at high frequency is a lot to ask, and not all circuits are quick to recover.

I have rode NT5's that will distort at the slightest hint of upper mid intensity, other mics I have used from Sennheiser, DPA, Schoeps, etc. (especially the MKH8040) don't have this problem.

Plush 20th July 2012 06:13 PM

Often this is observed when 48 volt phantom runs out of steam. The sound collapses under the intense volume assault. High voltage mics go a long way to alleviate the problem.

Also, may I mention that it sometimes has to do with singer technique.

The best singers in the world offer up a very even sound with high notes (often the really loud ones) not sticking out outlandishly and not jumping out at the listener. When you watch them sing, they seem to expend very little effort in making the wonderful vocal sounds. Let's face it--the best singers also have recorded a lot and some sing differently ( in a "recording voice") to microphones close to them.

Less experienced singers labor to produce their product and there can be an exaggerated dynamic range to their offerings. If they look like they're working hard to make the product, then I have found that they are sometimes very difficult to record.

MichaelPatrick 20th July 2012 06:24 PM

Thank you, guys, for all these thoughtful reflections.

fwiw, a project I'm working on is being affected by this problem. The mic is Schoeps CMC6 MK22 with CMC6 MK8 (M-S).

MichaelPatrick 20th July 2012 09:33 PM

I just called a brilliant guy to ask about this. He knows a great deal about acoustics and microphones and, after asking some questions about the setup, recommended I use a different capsule. He said the MK22 is "beamy on-axis" because it has no diffuser which is typical on cardioid mics.

I had not considered this because MK22 polar plots don't give any indications of it and I've had excellent results in other vocal applications.

I also asked him about possible limitation from 48v polarization to which he replied that in this case it "is not a problem."

Next time I'll try an MK21 or may pull out a trusty old MK4.

Celloman 21st July 2012 06:36 AM

Michael,
You might find that the distortion like sound is actually present at the source and accentuated by certain microphones or capsules.

Mike

Quote:

Originally Posted by MichaelPatrick (Post 8088011)
I just called a brilliant guy to ask about this. He knows a great deal about acoustics and microphones and, after asking some questions about the setup, recommended I use a different capsule. He said the MK22 is "beamy on-axis" because it has no diffuser which is typical on cardioid mics.

I had not considered this because MK22 polar plots don't give any indications of it and I've had excellent results in other vocal applications.

I also asked him about possible limitation from 48v polarization to which he replied that in this case it "is not a problem."

Next time I'll try an MK21 or may pull out a trusty old MK4.


Rick Sutton 21st July 2012 06:58 AM

Quote:

Originally Posted by Plush (Post 8087434)
Less experienced singers labor to produce their product and there can be an exaggerated dynamic range to their offerings. If they look like they're working hard to make the product, then I have found that they are sometimes very difficult to record.

That's what I have also observed. I don't have any solutions for remote capture (other than the obvious: using the best gear at the most conservative gain usable) but in a studio multitrack situation I have relied on a 2 mic approach. One mic (usually a ribbon) is recorded at a lower gain and used only for the peaks that stress the primary mic. Maybe a little difficult to balance but can be a life saver.

MichaelPatrick 21st July 2012 07:21 AM

Update
 
We changed three things in today's session and the problem disappeared:
  1. MK21 instead of MK22 and re-aimed the axis, putting it over the soprano's head. The singer also moved forward a little bit.
  2. On strong forte passages the singer turned 30 degrees to reduce on-axis energy.
  3. We moved the piano back 3 feet, opened the lid from short to full stick and turned the tail upstage, away from the singer, so the hinge was no longer exactly 90deg to the soprano and the main microphone.
My analysis

The MK21 is warmer and the pattern is more generous. The diffusing grill in front of the capsule probably reduced on-axis pressure. Moving the soprano forward made it possible to open the piano lid full stick and still keep them in balance.

Asking the soprano to turn a little bit on fortes was a no-brainer. Once she got it the improvement was obvious.

Moving the piano back and opening the lid gave us a fuller piano sound and it was still balanced because the soprano had moved forward a little.

Finally, we turned the piano's tail back away from the singer by about 15deg. We discovered, to my surprise, that the singer's forte passages consistently made the strings resonate, producing a high-pitched flutter that contributed significantly to the distortion we were hearing. Changing the angle stopped direct reflections and moving it back reduced her energy hitting the strings.

Problem solved!

BTW, this is a recording session, not a concert, but the lessons I've learned may be helpful in future concerts.

daivadisc 21st July 2012 09:18 AM

Soprano distortion
 
Many years ago a veteran sound engineer played me his recording of a soprano that appeared to be afflicted with very bad i.m. distortion. The recording was made using his RCA 77 ribbon mic into, probably, an Ampex tape recorder -- or maybe even direct to acetate disc.

When he heard the distortion, he went into his studio -- and discovered that that's the way she sounded!

There are some things that are our fault ... and others that aren't!

daivadisc

David Spearritt 21st July 2012 09:49 AM

Quote:

Originally Posted by daivadisc (Post 8089281)
When he heard the distortion, he went into his studio -- and discovered that that's the way she sounded!

This was precisely my point and what I have experienced most reliably.

I wouldn't like to distract the singer by asking her to move her head during performance. She needs to concentrate on the music.

MichaelPatrick 21st July 2012 05:26 PM

Quote:

Originally Posted by David Spearritt (Post 8089323)
I wouldn't like to distract the singer by asking her to move her head during performance. She needs to concentrate on the music.

In my experience most pros can adapt to reasonable requests that improve their performance. When she heard the difference she was glad to do it.

BTW, she turned her whole body. Turning just her head would have uncomfortably altered her instrument.

edva 22nd July 2012 04:05 AM

Quote:

Originally Posted by MichaelPatrick (Post 8089180)
We changed three things in today's session and the problem disappeared:
  1. MK21 instead of MK22 and re-aimed the axis, putting it over the soprano's head. The singer also moved forward a little bit.
  2. On strong forte passages the singer turned 30 degrees to reduce on-axis energy.
  3. We moved the piano back 3 feet, opened the lid from short to full stick and turned the tail upstage, away from the singer, so the hinge was no longer exactly 90deg to the soprano and the main microphone.
My analysis

The MK21 is warmer and the pattern is more generous. The diffusing grill in front of the capsule probably reduced on-axis pressure. Moving the soprano forward made it possible to open the piano lid full stick and still keep them in balance.

Asking the soprano to turn a little bit on fortes was a no-brainer. Once she got it the improvement was obvious.

Moving the piano back and opening the lid gave us a fuller piano sound and it was still balanced because the soprano had moved forward a little.

Finally, we turned the piano's tail back away from the singer by about 15deg. We discovered, to my surprise, that the singer's forte passages consistently made the strings resonate, producing a high-pitched flutter that contributed significantly to the distortion we were hearing. Changing the angle stopped direct reflections and moving it back reduced her energy hitting the strings.

Problem solved!

BTW, this is a recording session, not a concert, but the lessons I've learned may be helpful in future concerts.

Good post, thanks.

MichaelPatrick 24th July 2012 12:43 AM

Quote:

Originally Posted by edva (Post 8091609)
Good post, thanks.

YW ! cooge

12ax7 24th July 2012 01:08 AM

.
I can personally attest to the fact that sometimes a soprano's voice can sound like it's "distorting" even without any sound gear at all:

I once did sound for a variety show in an old opera house (built before electricity), and one of the acts was an operatic soprano with piano accompaniment.

When I was setting up, the soprano searched me out, came up with kind of a worried look, told me her name, and asked what I planned to do for her act.

I quickly looked her name up on the list: "Oh, you're the soprano with piano? In THIS place? -- I was planning on turning the amps off to make sure there's no hum or hiss!

(She looked at me like I had just given her a bouquet of roses!)

...During the show, I heard what I could have sworn was distortion (and actually double-checked to make sure I didn't accidentally have an amp on / mic up).

-- Nope. All amps were cold.
.

GIACOMO-_ 1st August 2012 07:05 PM

Soprano ? TLM 170. Always.

tvanderbrook 3rd July 2013 04:58 PM

Thank you for starting this thread, Michael. This is anwering a lot of questions for me!

I am grappling with some choir recordings I need to mix that have a LOT of what sounds like IM distortion. I think it is not the gear, as I've used different mics and cables with them, and the distortion sound appears to be consistent (and the Millennia and Apogee part further in the chain specs out in the clear.)

Also, I'm doing some soprano and piano recording coming up in September.

The explanations in this thread make the most sense to me as to the distortion sound.

The last time I recorded her I used two UM17Rs in ORTF and wide cardioid at around 5' high, about 6 feet or so away. Schoeps CMT30s in cardioid in ORTF back and up for room sound. This yielded acceptable results.

When I do the next session, I will record copious notes.

She stood in familiar recital formation with the piano, although I think I was able to get her to stand a little further away than she's used to, in order to help downplay the piano volume in her mics.

When you say you re-aimed the MK21's axis, aiming it abover her head, where exactly was the mic placed? In front of her face?

My soprano, through some trial and error experimentation with a previous engineer has found that she prefers her sound when the mic is no higher than chest level. When it is higher, it is getting to many overtones that are important for projection in a hall, but sound overly bright up close. I wonder due to your findings I could have the mic higher, but focused off axis from her mouth (i.e., pointed over her head) and get good results.

PJWeitzner 3rd July 2013 06:31 PM

Full stick usually always better
 
I think one should pretty much always use full stick. This is much better for clarity and I don't think volume is affected. A good pianist can adjust to this very quickly. I'd love to hear other thoughts on half/full stick.

tvanderbrook 3rd July 2013 09:29 PM

I agree soundwise, but the trick is having a pianist who doesn't have excessively heavy hands.

David Spearritt 3rd July 2013 10:29 PM

Quote:

Originally Posted by PJWeitzner (Post 9195154)
I think one should pretty much always use full stick. This is much better for clarity and I don't think volume is affected. A good pianist can adjust to this very quickly. I'd love to hear other thoughts on half/full stick.

With a professional singer, I always try to encourage full stick. As you say, a professional accompanist can adjust and balance without fuss.

Dpro 4th July 2013 01:38 AM

Hmm interesting I have experienced this as well with the singer I work with who is also a Soprano. Its interesting because it usually only happens when she is going up high. When she sings low its fine. It baffle me as well, I will suggest she try turning her body on the high parts. to move some of the energy off axis.

kstrauss 4th July 2013 02:47 AM

Quote:

Originally Posted by MichaelPatrick (Post 8086067)
Operatic sopranos can distort in recordings and even in playback on some systems, yet there's very little written in English about this phenomenon that's searchable on the internet. I would love to pick the brain of a skilled Tonmeister who frequently records opera or has experience with critical Soprano recordings.

Leaving out obvious causes like analog and digital clipping, what other causes are there for this particular kind of distortion -- and what can be done to prevent it or fix it in post if the signal appears clean but sounds bad?

It's called squillo. To project over an orchestra singers emphasize the higher harmonics in their voice which allows it to carry better and penetrate through a thick orchestration. With some singers the squillo tone sounds like distortion when the mics are relatively close to the singer, especially in the high register. It tends to mellow and just become bright the farther away you get. The best way to deal with it is to work with your soprano and have her place her voice "lower" aiming for a rounder, warmer tone. Tell her she does not have to project to the back of the hall. You can also, as has been mentioned, put the microphone at chest level and/or try a ribbon mic.

king2070lplaya 4th July 2013 04:47 AM

Squillo is a tenor vocal technique, not really used by other voice types, so I'm not sure that's the correct term to use about this problem with the soprano voice.

I've heard several explanations, from 48v phantom not being high enough voltage to accurately capture the source to actual acoustic anomalies.

I do not have the technical understanding to elaborate on the first, but I have, when listening to singers live, heard some distortion-sounding artifacts actually coming from the singers mouths. It is typically worse on less-polished singers, though I've heard some great ones do it in moments of intensity too.

This was of course on an operatic singer where they are REALLY spinning the air in the high range, so I'm not really sure how this would happen in a choral setting, as the massed singers do not project in quite the same way as a soloist does. My guess is that it's a mechanical problem in the chain. Maybe a less-than-stellar mic or a gain-staging problem?

boojum 4th July 2013 08:01 AM

Squillo - Wikipedia, the free encyclopedia

Thomas W. Bethe 4th July 2013 01:21 PM

I did a studio recording of a lyric soprano. She had a GREAT voice. I spent about an hour trying to get just the right sound for her. Most of the time was finding the right microphone for the job and finding the best spot to put it in. I too noticed some distortion on her voice but when I went into the studio I heard the same thing I was hearing in the control room. The recording came off very well and she was pleased with the results. The other problem I had was that the piano was in one studio and she was in another due to the way this place was constructed. She was a real trouper and made it all seem like there were no problems at all. I wound up using a AT4050 about 3.5 feet away and positioned just below her chin.

king2070lplaya 4th July 2013 04:32 PM

Quote:

Originally Posted by boojum (Post 9197086)

I mean no personal offense by this, but I'm going to trust the word of a soprano Met-opera house singer who is also fabulous teacher that I am close with over a Wiki article whose "factual accuracy has been disputed". Obviously this doesn't mean I'm right, but that's where I'm at with it.

kstrauss 4th July 2013 09:08 PM

Quote:

Originally Posted by king2070lplaya (Post 9198196)
I mean no personal offense by this, but I'm going to trust the word of a soprano Met-opera house singer who is also fabulous teacher that I am close with over a Wiki article whose "factual accuracy has been disputed". Obviously this doesn't mean I'm right, but that's where I'm at with it.

You are correct that squillo is generally associated with the tenor voice, it allows a voice to project without actually being louder. However the technique of emphasizing higher partials is used by all voice types. With some voices the combination of vibrato, resonances in the mouth/vocal tract, and a bright tone can result in a sound that is "distorted" on certain notes. The same effect can be heard in choirs, especially when the sopranos are singing high and loud. Singers can usually dial this down if you ask.

king2070lplaya 4th July 2013 09:17 PM

A little OT but a fun story: I saw a production of Turandot a few years back, with a tenor who in person was kind of a smug D-bag. Anyways at the climax towards the end, the tenor modifies his vowel as he is going up a fourth to the loud, high C. Instead of "Turan-doh-aaaaaaaat", he sang "Turan-dah-aieeeeet", it sounded like a racist karate sound, lol! I almost starting busting up right there in my seat.