This one screwed with my head for a long time.
I'll start with what I see when I look to the heavens,...
That mic array is two mics short of the entire stage front package at this concert, below.
DPA-omni ......................................................... EW-omni -- *array* -- EW-omni .......................................................... DPA-omni
*Center Array* = Royer Stereo Ribbon and DPA 4028 sub-cardioid stereo pair as ORTF stereo
Wide L/R Flanks are DPA compact series omnis
This concert hall has just been made "famous" to all TV watchers as the concert hall with the insane triangle solosit in the chamber orchestra (Geico ad?). If you watch the ad, you can see the same hoops as the first image. /rambling.
The bassist. That is the biggest bass violin that you'll likely ever see, with a massive and deep voice.
The tracks were all discretly recorded as mono tracks, intended to be mixed later.
But, the arrays are intended as multiple discrete stereo recordings:
DPA-omnis as wide Spaced Omnis
EW-Omnis as 3' Spaced Omnis
Royer Ribbon as Mid-Side stereo
DPA sub-cardioids as ORTF stereo
And, a stereo piar of DPA4028 sub-cards at the rear of the audience, facing the stage.
In total, 5 stereo recordings were done.
As I stated earlier, I am a two channel stereo specialist for 35 years. I'm just recently, in the last couple of years, trying to learn mixing.
Now, none of the stereo patterns mentioned above would ever have issues with overt comb filtering issues, when properly placed, as they are minimalist arrays, with long proven track records. The one exception might be the widest spread omnis, which will often end up with the "hole in the middle", which the center array fills.
In my mixing effort, I tried mixing the widest DPA omni tracks with the center ORTF tracks, which should have been a safe mix. NOT.
The right center mic was focused on the big bass face plate. The left wide flanking omni was focused on the big bass rear plate.
When mixed, that giant voice of a bass, and I'm talking wall shaking voice,... it flat out disappeared.
Listen to the discrete tracks, massive voice. Mixed, bass disappears. This is some strng phasing shit, and its mind boggling.
OK,... lets try flipping polarity of mics.
Yea! the bass is back. But, it is now cleanly placed in the fourth violin spot from the left, right between the last standing violin, and the first seated violin.
WTF?
I tried various polarity flips between the four tracks, and, could never land him in his position in the mix.
The problem, I surmise, arose with the two left mics relating to each other in a + polarity for the face-plate of the bass, and a + polarity for the back-plate of the bass, which caused phase cancellations.
Eventually, I found a combination of things, along with a bit of HPF edit sweeps to the bass tracks to reduce the commonalities that were causing the phase cancellations.
The stereo tracks,.. tracked, split, enjoyed.