Continuing an oddball micing discussion here to keep from hi-jacking
another thread..
..In another thread, Chris Church proposed the idea of split omnis, with a homemade baffle blocking the rear, sides, and top/bottom of each mic. The baffle would be covered by acoustic foam. I've bought/ordered supplies to create this but haven't tried yet.
Have you tried anything like this? What do you think? Any tips?
Thanks,
Brendan
Thanks Brendan,
I've thought a lot along similar lines. My apologies jnorman, this is going way off topic, and I typed a long reply so I'll answer in that other thread to keep from hi-jacking this one.
One problem as I see it is that complex baffles get unwieldy and impractical. The little spheres in the surround rig above are a way of adding some high frequency directionality without unwieldy, sight-blocking baffles. I've used more traditional Jecklin-type baffles for side to side and front-back baffling, and Moke once posted about using padded chairs to block rear sound arriving at his spaced omnis up front at a seated concert, which is similar. Further along those lines I've considered using two small jecklin disks to get a bit more A-B spacing than a single disk of reasonable size allows, keeping each mic close to it's own disk so that the baffles can be relatively small and effective, but the two can be spaced further apart. The two baffles could then also be angled as well to make the directionality of the array point more forward. I still think that could be worth playing around with.
Turning the closed box idea inside out- If I could get away with it, I'd build a closed box shaped baffle with a non-sonic reflective exterior (think four Jecklin discs connected at the edges to make a box) and mount my four mics around the outside of it, or more simply use a hard, reflective surfaced box and boundary mount the mics on each face. I've drawn up weird star shaped baffles on the back of napkins that favor the front direction, but still pickup sound from all directions in an attempt to get more isolation between adjacent channels. For the same reason, the sphere baffles on the rig above all point more forward except for the back channel.
The baffling idea behind all that is somewhat similar to what your mention, but the motivation is different- One of the basic ideas that is important to me is that if I put a baffle up, I want a mic on the opposite side of it too. A big reason why I like recording with omnis and have extended that to surround is I’m drawn to their natural sound and the way they record the sense of space, the complete sound of the room. To me that quality is an essential component of a really good, open and natural sounding recording that takes me back to the event.
Because of that, one idea I’ve placed importance on is that I want the combined response of the entire array (considered as a whole) to have a somewhat even response in all directions, at least all horizontal directions, even though I might want to split up the circle unevenly between mics to favor the forward direction. So if I'm using 4 mics to record Left, Center, Right and Back channels, I might want the Left & Right mics favoring the front direction and the back mic picking up a wider angle for the back and more sides. That way I keep more of the room and crowd sound in the Back channel and the sound from the stage in the other three. I’m not blocking out sound arriving from one horizontal direction to a mic without picking it up with another mic instead. If I do just block out crowd sound to the rear for instance, it’s often still there, but just sounds muffled and less realistic to me, unless completely silenced, and even then the ambient room sound suffers. Believe it or not, I often find audience noises more acceptable in my surround recordings than my stereo ones for that very reason