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In Reply to: RE: Revisiting Heyser posted by tomservo on May 20, 2012 at 11:49:31
"The problem is you cannot easily record a live stereo image with two mics, there is no simple combination of spacing etc that "captures" the event and so most of what we hear was created with pan pots etc in the studio."
I've been a believer in this all along!
Cheers,
Presto
Follow Ups:
"The problem is you cannot easily record a live stereo image with two mics"
This can work just fine, assuming good acoustics, engineering and musicians. The Water Lily Acoustic orchestral recordings of Mahler's Fifth and Shostakovich's seventh symphonies are excellent examples of this.
On a smaller scale some of the Chesky jazz recordings have very natural stereo and were made with one stereo microphone.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Hi Tony
This is a topic I love!
It is true, if you take two microphones there is no combination of spacing that permits the genuine item to be captured accurately.
The Blumein technique comes a lot closer, it is a special case of two vertically stacked elements (with open backs usually) and unlike a simple pressure mic have a figure 8 pattern.
This does two important things, one, it is “mono compatible”, a single sound source produces the same signal phase / time on both mics.
This means you can sum them and not have all kinds of comb filtering that is present when you sum two or more mic signals that are in separate locations. In the horizontal plane, they are in the same location in time.
Two, the figure 8 pattern provides amplitude shading according to horizontal angle and this is why a signal to the left is louder on the left channel. Two pressure microphones in very close proximity produce the same signal but have no directional discrimination.
The weakness in that design is that that each mic has a figure 8 pattern while what you would like to capture is only what is in front, not the rear. Also, the shape of the figure 8 only allows a fixed degree of amplitude shading vs angle and so is limited to a two channel system as is used currently. Cardioid mics can be satisfying but their patterns change a lot vs frequency.
The microphone array thing I am working on is along this line but done an entirely different way.
It allows the sound to be detected as if it were from one point in space but can be divided into a large number of channels if needed.
Also, where the Blumein is not coincident in the vertical plane, this can be made to capture a full hemisphere from one point in space.
As you enjoy “stereo” image, please pop on a set of headphones and try a couple of the recordings they put on the web site at work.
These have no compression so you may have to turn the volume up to get to a real sounding level. Try the Harley or Trains and keep in mind this is a work in progress and only the front image, more or less the width of your vision.
Let me know what you think.
Best,
Tom
Recordings at bottom of the page;
http://www.danleysoundlabs.com/technical%20downloads.html
could also be used for recording, and reproduction. Onfotunately the standard array mics are a little noisy for music recording and a high quality low noise microphone would e costprohibitive at Qty 90.
And yes Blumein array is -IMO a nice recording technique - especially useful for the ambience feed to a recording or medium sized live events in the somewhat near field. A second (or 3rd) X-Y array can be used with appropriate delays to mix in ambience from the rear of the hall. For engineered recordings, M-S mic configurations for the individual performers and instruments are great - you can "place" the track anywhere adjusting the levles and delays relative to other tracks and the mix down to Mono is honest.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.
ABOVE is a reference to Belafonte at Carnege Hall... As being a stereo recording... IT IS NOT and the photos at the performance shows that,,, Harry is holding one mic and walking back and fort on stage,,,His band has two mics close to the floor not even matched spaced a couple of feet apart... Two other mics above his head are faceing away from his body tward the back of the stage,, A string section is grouped in another position on stage,,, NO imageing is produced,,,Also WHAT IS MOST INTERESTING ALL APPLAUSE SEEMS TO COME FROM THE FRONT ON STAGE WITH BELAFONTE,,...
about the applause coming from the front? You just pointed out how the mikes were placed. If they were cardioid types, that is to be expected.
Stu
The mics in the Belafonte concert are not pointed at the audience,,So how did the audience appear in front of you in reproduceing the mix of the recording.. When Belafonte asks the sections of the audience to respond,,Why did the section NOT give proper locolazation cues on the record ??
mountains of molehills.
If the mikes are omnis then the phenomenon you mention has an obvious explanation.
If the mikes are your typical cardiod pattern, which is a heart shaped pattern with the indentation being at the mike, you are capturing the sound off the sides and slightly to the rear.
Now take applause: can you identify individual people clapping? I don't think so. Applause is basically random noise and it literally echoes off the sides of the venure. Directionality concerning applause is basically impossible, not to mention that you have tremendous issues with phase, particularly wince applause tends to have severe "bounce" off side walls.
A normal mike will pick up a lot of the applause as it echoes off the side walls and the reflectors over the performers. The mike can not distinguish individual people clapping ( at lest for normal clapping) and so your ears perceive the clapping as being being all around.
Next time, try standing on a stage while the audience is clapping. The sound completely engulfs you, even if you are on stage.
If you want to hear applause as it should try a discreet four channel recording, like Kimber's Iso mike recordings.
Stu
The mics are in the photos and the manufacture can be identified..plus what way they are pointed,,So STEREO claimes are false....BELAFONTE is Obviously MONO..
All stereo recordings employ at least two mikes. What's wrong with more and then having to mix them down?
In a live performance, you can't have just two fixed mikes as the solo performer is moving around on stage. It isn't a studio. Concessions must be made to accommodate the performance.
Stu
There is a mono version of Belafonte at Carnegie Hall, but the stereo version actually is stereo, as in RCA Living Stereo.
Yes I know that...I have both,, But it does not answere my question.. RCA is pulling the wool over your eyes claiming a full stereo recording,,When on stage,,A full stereo mic setup did not exhist,,
The sound out the back of the figure 8's can be a benefit, as it provides hall ambiance. If this proves excessive, the microphones can usually be moved closer.
The big downside of minimal microphones is that the musicians are responsible for the balance and it won't be easy to fix their mistakes. It will be impossible to "Autotune" bad vocalists, but that's a good feature, IMO :-)
Comb filtering is a big problem when spatially separated microphones are mixed into a single channel. It is less of a problem when each microphone has its own speaker, as the ear hears these two cases differently at high frequencies.
My late wife loved your "Train Start" recording. I will listen to the newer ones when I get the chance. But it will be on speakers, as I don't have any decent headphones, just a handset that I use for Skype.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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