Yes, but that means that for modern music we have no real concept of 'hi-fi' as there is no acoustic performance to reproduce. The 'recording' is actually a production in its own right. Nothing wrong with this, except that it belongs in a different thread where people can talk about the best way of miking particular instruments including electronically enhanced instruments. Of course there is some crossover if the piece is Turangelila with an Ondes Martineau!00940 said:
I guess I had in mind a less stringent definition of acoustic event. For example a small jazz quartet with some instruments (or voices) being amplified but not others. I'd want to record the voice of the singer directly, not the sound going through the PA. The recording would actually be more faithful to the acoustic performance, under some respects, than what the audience is experiencing.
Fully unplugged, in a good room, with good performers and the time/freedom to find the golden spot for the stereo pair, ok why not. But it's such a difficult setup that it's not hard to see why the industry moved away from such methods in most cases.
Fully unplugged, in a good room, with good performers and the time/freedom to find the golden spot for the stereo pair, ok why not. But it's such a difficult setup that it's not hard to see why the industry moved away from such methods in most cases.
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First I want to say that a recording that is identical to what you hear in the audiance ( dummy head) sounds bad, way to much room and audiance noise that the brain filters out when your there. I recorded small classical combos, 2 to 8 instruments in live performances twice a week for a year at the Banff centre for the Arts. Some of the musicians complained that they didnt want to see the mics so we recorded with a Nueman dummy head in the front row. As we expected, they hated the recording. A pair of mics would usually do unless there was a piano. It always needed a spot mic ( read about the 3 to 1 mic spacing rule to prevent comb filtering) or it would get lost in the reverb. (the piano was typically at least twice the distance from the other instruments) and Unfortunately the room sucked. The pair was usually an xy pair or spaced omnis or something in between. ( like a pair of u87s a foot apart in cardiod patern, but if you look at the specs these mics turn into omnis below a certain freq. so this is both a spaced omni and a xy card pair.) Blumlien pairs pick up too much from the rear. And the most important aspect, which you may have no control over is the placement of the musicians, there acoustic mix, how much they move, etc.
Have a look on his site, he was dissatisfied with many live music recording techniques so tried doing his own
That's exactly what this thread is about.
Situation: you have two mics to position in a venue with a 100-piece orchestra playing.
Where do you position the mics in order to achieve a convincing stereo image when played back through a conventional HiFi system?
You can replace "100-piece orchestra" with jazz sextet, string quartet, or whatever.
Some multi-instrument event is happening without reinforcement. The musicians are acoustically mixing themselves on-stage, and all we have to do is capture a good recording of that. Where do the mics go?
It's a purely theoretical discussion, but I thought it'd be an interesting one.
You could do ORTF at some location in the venue, but I don't know if having the mics pointing at some distant walls is the best thing to do.
XY means phase coherency throughout the stereo image, but is that a requirement for good stereo reproduction? Would it be better to introduce the time-of-flight differences that spaced mics bring in?
Here's a link that might be of interest: Comparison of different microphone positions for orchestra instruments: Violin
What's interesting there (IMO) is that the sound of most instruments varies a lot by height, so the "correct" height to record would probably be at audience/conductor ear height.
Chris
Where to place the stereo mics?
Where it sounds best.
Procedure: Put musicians in room, listen to the sound, walk through the room, put mic where it sounds best.
Yes it is really that simple.
Now deside what microphone technology is suited to the music and acoustics. Some coincedent microphone technologies allow you to vary the amount of ambience and width of the soundfield after recording.
In live TV concerts, soundfield mics are often used, because these recordings can easily be altered. These mics can also give a very accurate stereo field, kinda important for live TV concerts.
The mics high up in concert halls are used for adding ambience. These are never main mics.
Where it sounds best.
Procedure: Put musicians in room, listen to the sound, walk through the room, put mic where it sounds best.
Yes it is really that simple.
Now deside what microphone technology is suited to the music and acoustics. Some coincedent microphone technologies allow you to vary the amount of ambience and width of the soundfield after recording.
In live TV concerts, soundfield mics are often used, because these recordings can easily be altered. These mics can also give a very accurate stereo field, kinda important for live TV concerts.
The mics high up in concert halls are used for adding ambience. These are never main mics.
A discussion of coincident vs spaced and the emergence of the Decca tree by Ron Streicher : The Decca Tree - Mixonline
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https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=21&cad=rja&uact=8&ved=2ahUKEwiI1evGl4LiAhVNbKwKHQT7B6MQFjAUegQIBBAC&url=https%3A%2F%2F522bb370f5443d4fe5b9-f62de27af599bb6703e11b472beadbcc.ssl.cf2.rackcdn.com%2Fpublication%2Fupload%2F837%2Fmicrophone_techniques_for_recording_english.pdf&usg=AOvVaw1tWdibgIU2H7fLIC2DXEu_
imo, the most important is to get a good sound of all the mix before recording, so the mic and placement and mixing should be optimal before recording. Less adjustments later the better the result.
imo, the most important is to get a good sound of all the mix before recording, so the mic and placement and mixing should be optimal before recording. Less adjustments later the better the result.
The desired direct-to-reverberant ratio must be considered before the mike mounting.
This will also depend on the expected playback environment and the listeners' tastes.
When D-to-R ratio goal is defined, and a mike technique is picked, distance from source as a function of room critical distance falls out of basic directivity acoustics.
However some rooms just don't sound good much beyond critical distance. The in-room audience may not complain but on later playback it sounds crap.
This will also depend on the expected playback environment and the listeners' tastes.
When D-to-R ratio goal is defined, and a mike technique is picked, distance from source as a function of room critical distance falls out of basic directivity acoustics.
However some rooms just don't sound good much beyond critical distance. The in-room audience may not complain but on later playback it sounds crap.
As mentioned before, some microphone technologies allow you to change the direct to reverb ratio after recording. Examples are XY, MS and soundfield.
And if, as a consumer, you have an upmixer and surround sound, then you can change the direct to reverb ratio yourself just by changing the level of the surround channels.
I'm afraid this is incorrect.
M/S allows you to change the stereo width (ranging from mono centre all the way out to 100% stereo difference and nothing mono). The direct-to-reflected ratio is a function of mic position, mic pickup pattern, and room acoustics.
Stereo width and direct-to-reflected sound ratios are not the same, although I can see why you might conflate the two.
Chris
I kind of see them as the different sides of the same coin.
The S mic doesn't pick up direct sound at all, it's all ambience. The M mic, depending on polar pattern, can pick up ambience but it doesn't have to be a lot.
With XY mics you can change the width of the stereo image by changing the angle of the mics.
And by adding and subtracting the mic signals, you can go from MS to XY and visa versa. Hence my to sides same coin. But I can be wrong.
Those are ambiance, audiance mics, mostly to record applausse. And I'll say it again, No one records with mics in the audiance, too far away from the music. It ends up burried in reverb. Most people start with a stereo pair above the conductors head and go from there. Hes the mixer, so it follows that the instrument ballance is correct in that spot.
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Not sure how, "after recording", "changing the angle of the mics" does anything?
I would not agree that "the S mic doesn't pick up direct sound at all". Does depend on orchestra width and mike placement. But MS was never my thing.
Yes, SoundField is interesting, almost distressingly so. (You can spend hours playing around in post-production.) But expensive.
And what is "reverb"? Classic acoustics simplifies to Direct and Reverberant fields, and assumes the reverberant is uniform in the whole room. The long tail is obviously uniform. But the Early Reflections are very location specific, and are KEY clues to the ear.
If music rooms were properly designed there would be "good" early reflections over a large area in front of the orchestra. Very few rooms meet this criteria.
When I documented music performances nightly, we had two popular minor rooms. One had a cylindrical stage shell and too-early reflections focused to a single spot (singers liked that spot). The other had an open back-space with heavy draperies and NO useful early reflections in the lower half of the room. A third, 'good', stage had NO lateral early reflections but a big overhead reflector with no diffusion. In that space I could only avoid "ceiling bounce". Oddly, mikes high in the back above the lighting booth sounded almost decent: the baseball-diamond shape "came together" up there with decent image but spoiled by blower rumble.
Not sure how, "after recording", "changing the angle of the mics" does anything?
What I meant is that the changing of the angle of the xy mics is equivalent to changing the amount of s in a ms setup. Of cause you can't literally change the angle of the xy mics after recording. But you can change it into a ms signal and THEN "change" the angle of the xy mics.
An other way how I think about it.
Assume the angle of the xy mics is zero, then you have a mono signal. (this mono signal has of course a direct to reflection ratio that can't be altered after recording, just like you mentioned.) This mono signal has zero width. By changing the angle of the mics, width is added to the sound field. Just like adding the s signal to the m signal with a ms setup, they are equivalent. Soundfield mics are an extrapolation of this.
And if this is correct, this means that a stereo Soundfield is a mono signal with an ambience signal superimposed on top of it. Further extrapolation into surround means that a surround soundfield is a mono signal with multiple ambience signals superimposed upon one another.
But I'm speculating.
What I meant is that the changing of the angle of the xy mics is equivalent to changing the amount of s in a ms setup. Of cause you can't literally change the angle of the xy mics after recording. But you can change it into a ms signal and THEN "change" the angle of the xy mics.
An other way how I think about it.
Assume the angle of the xy mics is zero, then you have a mono signal. (this mono signal has of course a direct to reflection ratio that can't be altered after recording, just like you mentioned.) This mono signal has zero width. By changing the angle of the mics, width is added to the sound field. Just like adding the s signal to the m signal with a ms setup, they are equivalent. Soundfield mics are an extrapolation of this.
And if this is correct, this means that a stereo Soundfield is a mono signal with an ambience signal superimposed on top of it. Further extrapolation into surround means that a surround soundfield is a mono signal with multiple ambience signals superimposed upon one another.
But I'm speculating.
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