Topic: mic placement for matrix purposes

[nicegrin]

Hi!

I plan to record using 2 omnis and 2 hypers and wondering if it makes any difference (i.e. what config will sound the best) depending on the following mic placements:

1. Omnis spaced like 16 cm apart and hypers spaced 18 cm apart   like: (H, O, O, H).

2. Like 1 but in (O, H, H, O) config.

3. (O,H,O,H) with same spacing between the two omnis and the two hypers.

Furthermore, anything else to consider such as different stereo placement teqniques (ORTF,XY etc...) for the different mic-types that would be prefered when matrixing them together?

Thanks! 




 

[Brian Skalinder]

When I was playing around with 4-ch mic mixes, I found I preferred one pair coincident, the other pair spaced or near-coincident.  For example, hypers XY (with an appropriate included angle) + spaced omnis (with an appropriate spacing).

[boojum]

When I was playing around with 4-ch mic mixes, I found I preferred one pair coincident, the other pair spaced or near-coincident.  For example, hypers XY (with an appropriate included angle) + spaced omnis (with an appropriate spacing).

Exactly.  Close to this is the standard ORTF card array in the center with omni flankers about half the distance from the ORTF to the edge of the stage on either side.  I have run ORTF with omni AB at ~40cm spacing and that works fine as does MS with the same omni array.  The deal is to get the omnis on the outside for the room sound. 

[Gutbucket]

When I was playing around with 4-ch mic mixes, I found I preferred one pair coincident, the other pair spaced or near-coincident.  For example, hypers XY (with an appropriate included angle) + spaced omnis (with an appropriate spacing).

Same here, coincident center pair with spaced omnis. 
I like that it gives you the most usable options to play with if you're so inclined (or even if you aren't now, but think you might be at some point in the future)-

1) You can obviously use either pair alone as a standard 2-channel stereo recording.
2) I find a coincident center pair mixes easier with the spaced omnis without phase combing issues when matrixing, which I think is the angle Brian is coming from.
3) You can play with combining the coincident center pair to mono (which works fine since they're coincident) and using that to reinforce the center image of the spaced omnis in a three channel mix to stereo.  (similar of like the old, historic Mercury recordings)
4) Same as 3) but instead of mixing the 3 channels to stereo, send that center mono signal to the Center channel of your 5.1 home theater reciever and route the omnis Left/Right.
4) Going even crazier with the suround playback matrixing above, send the difference signal from the omnis to the surrounds.. endless geek fun.

One thing you can do to make any mixing/matrixing options even more likely to work well is consulting the Stereo Zoom charts for setting up the A-B spread of the omnis and the mic angle between the coincident hypers so that both pairs of mics have similar recording and playback angles.  That's a good way to determine the appropriate spacing for the omnis and angle for the hypers.

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When I was playing around with 4-ch mic mixes, I found I preferred one pair coincident, the other pair spaced or near-coincident.  For example, hypers XY (with an appropriate included angle) + spaced omnis (with an appropriate spacing).

Exactly. 

I'll agree as well, if you are running all 4 mics in the same location; this is what I'd do, a coincident set flanked by the omnis. If you can run the mics separately, then your hypers become the dominate source with the omni's run up front for stage sound.