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Classical songs

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Re: Classical songs

Postby Vox Gnus » Fri Jun 26, 2020 6:38 pm

Note, he mentioned that he'll be recording with a Zoom F6, so it's safe to assume he can use it in 32-bit mode. No need to set levels, although mic position will be critical.

Assuming the soprano is in the cove of the piano (they usually like to stand with the right hand on/near the body of the piano, so beware of tapping noises from any rings the singer might wear), I'd think you should play with an NOS setup, but don't have it directly on axis of the singer. You might find that having it particularly high (or even way down near the floor) helps keep the singer's brightness in check.

Ultimately, it depends on the room and the balance between the performers. Move the mics around, play with the music, and have fun!
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Re: Classical songs

Postby hooty2 » Mon Jun 29, 2020 4:20 pm

Hi... hope this is relevant and not intrusive.
I sent the sengpielaudio link to a friend.
How would people assess and respond to friends reply?
"...Am I correct in thinking the general approach is... Find favourite distance from musicians where it sounds best (direct / room sound) point mics at outter performers, and the formula tells you the distance between the capsules?..."
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Re: Classical songs

Postby Hugh Robjohns » Mon Jun 29, 2020 4:58 pm

Well, he's along the right general lines....

Find favourite distance from musicians where it sounds best (direct / room sound)

This is correct. The starting point is to determine the optimum position for the mics to achieve the desired direct/reflected sound balance -- bearing in mind that (1) this balance is changed if the polar pattern is changed (as it can be if using multi-pattern mics or MS arrays), and (2) it will always be drier in the summed mono than in stereo so some position compromise may be required if the mono sound quality is deemed important. (ie, err towards being more distant rather than less!)

point mics at outer performers, and the formula tells you the distance between the capsules?..."

Not quiet...

From the chosen mic position you need to estimate the angle which spans the intended width of your final stereo image. This angle is called the stereo acceptance angle (SRA).

For example, in the case of an orchestra it is normal to have the back row of the first violins more or less fully left, and the back row of the cellos or basses fully right. So I would draw an imaginary line from the mic position to just left of the last violin desk, and just right of the last basses desk, and then estimate the angle between those lines to give me a target SRA.
SRA graphic.png


In the case of smaller ensemble, the instrumentalists might fill a smaller proportion of the whole stereo image with the outer portions effectively containing just room sound/reverberation...for example. Each case must be judged on its merits and the required stereo image of the final production.

When you know the required SRA, and the mic polar patterns, the Sengpiel website -- or the Neumann App which I much prefer* -- can be used to offer suggestions for the appropriate mutual angle between the mics and the capsule spacing that will provide that SRA.

In general, if you increase the capsule spacing you will decrease the mutual angle to maintain the same SRA (and vice versa). For example, coincident Hypercardioids with the traditional 90 degree mutual angle gives an SRA of 109 degrees. But if you space the mic capsule by, say, 20cm, the mutual angle needs to be reduced to 45 degrees to maintain an SRA of 109 degrees.

Spacing the capsules introduces inter-channel time-of-arrival difference information while the mutual angle and polar pattern combine to create inter-channel amplitude differences, and that t-o-a information is usually perceived as giving a more spacious sound character at the expense of less imaging precision.

Of course, if you decide to change the polar pattern then the physical location of the mics in the room may well need to change, and so the SRA will change and you'll need to go around the loop once again.

...And even when you arrive at a specific solution of polar pattern, position, SRA, mutual angle and spacing, it's quite possible than on hearing what you're getting you may need to jiggle things around a bit to full optimise the setup and match your aesthetic requirements.

...And don't forget that these SRA-based processes don't take the mic height into account which may also need to be adjusted independently to achieve the desired front-back perspectives and balance of a large ensemble like a big choir of orchestra!

*Neumann Recording Tools app is preferred by me because it's more convenient on the phone on site, and it's more interactive.
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Re: Classical songs

Postby guttenor » Sat Jul 04, 2020 7:23 pm

Hugh Robjohns wrote:Well, he's along the right general lines....

Find favourite distance from musicians where it sounds best (direct / room sound)

This is correct. The starting point is to determine the optimum position for the mics to achieve the desired direct/reflected sound balance -- bearing in mind that (1) this balance is changed if the polar pattern is changed (as it can be if using multi-pattern mics or MS arrays), and (2) it will always be drier in the summed mono than in stereo so some position compromise may be required if the mono sound quality is deemed important. (ie, err towards being more distant rather than less!)

point mics at outer performers, and the formula tells you the distance between the capsules?..."

Not quiet...

From the chosen mic position you need to estimate the angle which spans the intended width of your final stereo image. This angle is called the stereo acceptance angle (SRA).

For example, in the case of an orchestra it is normal to have the back row of the first violins more or less fully left, and the back row of the cellos or basses fully right. So I would draw an imaginary line from the mic position to just left of the last violin desk, and just right of the last basses desk, and then estimate the angle between those lines to give me a target SRA.
SRA graphic.png


In the case of smaller ensemble, the instrumentalists might fill a smaller proportion of the whole stereo image with the outer portions effectively containing just room sound/reverberation...for example. Each case must be judged on its merits and the required stereo image of the final production.

When you know the required SRA, and the mic polar patterns, the Sengpiel website -- or the Neumann App which I much prefer* -- can be used to offer suggestions for the appropriate mutual angle between the mics and the capsule spacing that will provide that SRA.

In general, if you increase the capsule spacing you will decrease the mutual angle to maintain the same SRA (and vice versa). For example, coincident Hypercardioids with the traditional 90 degree mutual angle gives an SRA of 109 degrees. But if you space the mic capsule by, say, 20cm, the mutual angle needs to be reduced to 45 degrees to maintain an SRA of 109 degrees.

Spacing the capsules introduces inter-channel time-of-arrival difference information while the mutual angle and polar pattern combine to create inter-channel amplitude differences, and that t-o-a information is usually perceived as giving a more spacious sound character at the expense of less imaging precision.

Of course, if you decide to change the polar pattern then the physical location of the mics in the room may well need to change, and so the SRA will change and you'll need to go around the loop once again.

...And even when you arrive at a specific solution of polar pattern, position, SRA, mutual angle and spacing, it's quite possible than on hearing what you're getting you may need to jiggle things around a bit to full optimise the setup and match your aesthetic requirements.

...And don't forget that these SRA-based processes don't take the mic height into account which may also need to be adjusted independently to achieve the desired front-back perspectives and balance of a large ensemble like a big choir of orchestra!

*Neumann Recording Tools app is preferred by me because it's more convenient on the phone on site, and it's more interactive.

Thanks for your explanation and for recommending the Neuman recording tools! So, I suppose I should start finding the prefered "audience position" and check the SRA from that position and then position the mics (I use cardioids) relative to each other according to the Nemann app?

Judging from the Nemann app it seems that if I am recording in a relatively dry room with a narrow stereo image something like Ortf may be ideal. On the other hand if I am recording in a church with a wide stereo image something like xy-90 may be more ideal. Am I making the right assumptions?

And, for everyone who is curious, I will accomany the soprano on a grand piano.
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Re: Classical songs

Postby Hugh Robjohns » Sat Jul 04, 2020 7:28 pm

guttenor wrote:Judging from the Nemann app it seems that if I am recording in a relatively dry room with a narrow stereo image something like Ortf may be ideal.

Yes, in a dry room you'd want to place the mic array further back, and so would need a narrower SRA for a given recorded image width. ORTF or NOS would be good starting points with cardioids.

On the other hand if I am recording in a church with a wide stereo image something like xy-90 may be more ideal. Am I making the right assumptions?

In a very reverberant space you would need to go closer and thus need a wide SRA, so crossed cardioids might be more appropriate.
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Re: Classical songs

Postby guttenor » Sun Jul 05, 2020 3:44 pm

Hugh Robjohns wrote:
guttenor wrote:Judging from the Nemann app it seems that if I am recording in a relatively dry room with a narrow stereo image something like Ortf may be ideal.

Yes, in a dry room you'd want to place the mic array further back, and so would need a narrower SRA for a given recorded image width. ORTF or NOS would be good starting points with cardioids.

On the other hand if I am recording in a church with a wide stereo image something like xy-90 may be more ideal. Am I making the right assumptions?

In a very reverberant space you would need to go closer and thus need a wide SRA, so crossed cardioids might be more appropriate.

I read an informative reply you wrote regarding the recording of a pipe organ:
https://www.google.com/amp/s/www.soundo ... rgan%3famp

More specifically, I'm interested in the things you wrote about critical distance. Is the Dc something I should always try to find, regardless in what room I'm recording in. Is it even possible to find the Dc in a room with a minimal amount of reverbance.
Also, you said the prefered distance from the source with cardioids is about Dc/2. Would you say this distance is also preferable when you are recording a chamber ensemble or, in my case, grand piano and song?

One more question: the SRA obviously needs to be wider than the physical width of a small chamber ensemble, or a pipe organ for that matter.
Are there any guidelines for how the width of the SRA vary in relation to the distance from the source or in relation to the amount of reverbance?
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Re: Classical songs

Postby Hugh Robjohns » Sun Jul 05, 2020 4:16 pm

guttenor wrote: Is the Dc something I should always try to find, regardless in what room I'm recording in.

Yes... It's an essential element in deciding the position of a mic array. But with experience it can be judged pretty accurately by ear.

Is it even possible to find the Dc in a room with a minimal amount of reverbance.

It's always possible to calculate, if not physically measure, but it's certainly possible for the Dc to be outside the maximum dimension of the room.

Also, you said the prefered distance from the source with cardioids is about Dc/2. Would you say this distance is also preferable when you are recording a chamber ensemble or, in my case, grand piano and song?

It's regardless of the source -- it's just about the wet/dry balance. But it is a starting point; you can still move the mic a bit closer/further to adjust the perspective as required to suit the material.

Are there any guidelines for how the width of the SRA vary in relation to the distance from the source or in relation to the amount of reverbance?

The SRA is just about how you want the sources to fill the stereo width.
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