Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion HiFi & HT Chat Live Multichannel Recording techniques

Sitting in Boston Symphony Hall the other evening, I counted about 30 microphones distributed around and over the stage and hanging over the front quarter of the audience. (Part of DG's recording project of the Shostakovitch symphony series.) Obviously the final product will be a mix of these inputs.

Got me wondering if anyone has tried a multichannel recording using just 5 quasi-directional microphones set in the audience and placed/oriented akin to a home theater speaker setup. On one hand such a protocol would seem to have the potential for making a home theater experience very similar to that when physically sitting in the audience of a live performance. The downside I suppose is that the recording would include all the coughing, paper shuffling and other distractions that I'm finding increasingly annoying at the BSO. (Don't people know to stifle their coughing!)

What is the standard procedure for multichannel recording - create it by mixing after recording using many many microphones, or simply recording 5 channels directly and just going with it?

I see there is a new thread about the possibility of MCH MQA over on the Meridian Sooloos forum. As my musing is more general in nature, I thought I'd post it here.

The microphone technique used will depend on whether you want an accurate reconstruction of the soundfield at home (e.g. using ambisonics or even wavefield synthesis - WFS) or some sort of acoustically processed version, which is what the multi microphone method will give you. The multi mic version you describe is sort of old fashioned quad and that never really worked all that well if what was wanted in playback was to sound realistic and natural, hence the demise of quad except for its Dolby-type variants (5.1, 7.1, Atmos, ProLogic etc).

How about using a tetrahedral mic (e.g. Soundfield, CoreSound Tetramic, Brahma or even a home made version)? You can then mix the B-Format channels to make any virtual mic polar pattern you like and retain something closer to the soundfield at your preferred listening position. The B-Format archive retains the acoustic data, if I can put it that way, in pressure and velocity terms (channels). Spot micing or spaced mics can still be added to taste and mixed in, but you still retain the focus of the original listening position soundfield.

Meridian surround DSPs since the 565 support ambisonics in its UHJ 2-channel version and 3-channel B-format (both are horizontal isotropic systems).

On theme but OT I attended a drum recording master class last night at Soundattak in Colchester UK.
We started with going from a two mic set up to using 9 in stages.

I was invited by Jonathan of Little Rabbit Barn fame along with two of our live sound engineers.

This was very interesting and went along way to show what can be done with correct set up.
We covered the Glyn Johns method where correct mic placement distances are crucial and it was amazing to experiance that when correct in recording, the stereo image just popped out of the PA on playback.
Apparently when recorded like this no post production EQ or compression etc is required.
If you mic it correctly, you record it correctly.

Another section was the importance of choosing the correct snare drum for the style of music and the kit. We had about six differant ones to demonstrate this.
One of the snares was the actual 1957 drum that was used to record the 'Only Fools and Horses' theme.

Mixing the kick drum with three Mic's and using differant placings was a revelation.
The importance of Phase when micing up a snare from top and bottom as well as mic distances. Phase is crucial here. As is direction. Point the mic at the edge of a Cymbal is a very bad idea as the sound fluctuates with the movement. Point it centre.

We also used high quality ambiance Mic's to mix in on playback for great natural reverb. They can cause feedback on live reinforced sound so caution is needed.

The other tip was the ninth mic place in front of the kit which should be the cheapest and nastiest you can find. This is then fed through horrible overdrive deliberately.

Without this we had a perfect clinical drum recording, then as you fed this distortion into the mix the whole recording lifted to a new level with some edginess, grit.
Apparently this technique was developed by U2. Fascinating to experience.

We used Shure Mic's and pro tools to record.

I am no expert here, but this was fascinating.
Chris