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Gear / Technical Help => Microphones & Setup => Topic started by: GDfan on November 04, 2017, 01:13:06 PM
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I want to use the 3rd channel on my MixPre3, I was thinking of 2 cards ORTF and a omni (?) in the middle. Neumann SKM184 and an AKG314. I can set the AKG314 to subcard, omni, hyper or figure 8. I was leaning towards omni, but maybe setting it to subcard instead. thoughts? I have considered pair of omnis with the card in the middle but I want to run this for the Dead & Co Florida shows and the arenas might not be best for split omni.
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There is a pretty informative thread about a mic for the third channel of a MP3 in this subforum. I'd find the link but I'm on my phone. You should be able to find it pretty easily though.
ETA: http://taperssection.com/index.php?topic=182566.0
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Thanks for the link. still on the fence. might try omni one night and subcard the next.
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I was thinking of 2 cards ORTF and a omni (?) in the middle.
The microphone angle and spacing of ORTF is optimized for two microphone channels using a pair of cardioids. When introducing a third microphone in the center, you'll want to increase spacing or angle of the outside pair or both, unless you are using an omni and low passing the signal with the intent of only reinforcing the bottom octave and a half or so. Otherwise the stereo width will collapse towards mono significantly, and you might also hear comb-filtering from too much "bleed" of similar content across the three channels when mixed down to two. Nothing wrong with using the center mic to only reinforce the very bottom- that preserves "ORTF-ness" and maintains simple 2-channel stereo microphone technique above the low bass region- but to my way of thinking it discards a lot of the potential goodness a center mic can provide.
More optimized options-
Double the standard ORTF spacing and angle the mics further outwards (point them 180 degrees apart facing directly to the sides).
Triple the ORTF spacing and leave the mic angle the same.
Quadruple the ORTF spacing and PAS.
The less ideal the acoustic / further back you are in the room, the more a more narrowly-angled but wider-spaced configuration becomes advantageous. If you change one thing (spacing, angle, number of mics) you also need to change the others to compensate.
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If you cannot increase spacing for whatever reason, pointing the Neumann cardioids fully sideways and setting the AKG314 to hypercard or figure-8 is what I'd do if I was constrained to a narrow spacing arrangement typical of a 2-channel stereo pair. I know it's hard to accept sideways pointing mics. But if your ability to increase spacing is limited, angle the cardioids as far apart as you dare and use a more directional center mic.. or just plan to not use much of the center mic signal.
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:cheers:
Appreciate the info. I am going to digest it all and will let you know what I decide :)
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As a fan and user of the Oddball Mic Technique (OMT) and a few of it's variants I'll add:
We ran Wood Brothers with AKG ck61 ULS Cardiods wide PAS (~17-20 cm) with one ck22 Omni in the middle. I used the middle mic low in the mix and did EQ it with 2-3 octaves down starting about 2.5 kHz and above.
Depending on room acoustics I also advocate aiming the subcards sideways and adding the 314 in hyper/Fig 8 in the center (fig 8 if less crowd noise potential). The acoustic theory is sound for this. Unless you know there will be standing waves or a large open space is on one side or the other of the mics (kitchen, bathrooms, or such) you should be able to get a nice mix.
visualize it:
The subcards are a wide card pointed sideways (90'), so two aimed away from each other makes two lobes with holes in the front and rear.
Pointing a hypercardiod forward (0') adds a pinched lobe with a small tail in the rear to the picture- filling in the center forward hole and adding a small tail to the rear hole. (this rear lobe may provide an added sense of depth)
Pointing a figure 8 forward (0') adds a round lobe front (0') and rear (180')- filling in the center in a more omni way and adding a rear Omni-like lobe with a bit more detail than the hyper counterpart. ( A little bit more effort to mix this channel in properly; typically, for me at least)