I was at a concert last night, swiveling my head to look across a big stage and occasionally bopping along--omnis in a more fixed position on the shirt collar--and I realized that if I had had ear-mounted cardioids, the recording would have been a very seasick thing. Maybe XY or ORTF cardioids stably mounted in a sweet spot would be good too, would eliminate that backless void I hear (or don't hear) in front-facing cardioid recordings. Never tried it. But in the rough-and-tumble of concert recording, I'd always go for omnis as the first choice.
The phasing happens with omnis too, albeit not as bold.
On the bolded part of your quote, are you referring to cards in an A/B fashion where you state "front facing cadioids"?
Also, just one of many situations but, say running cards onstage, what benefit would it be to hear whats in back of you?
I can't really think of me ever wanting to hear whats behind me on a recording.
Also judging by the bolded sentence, it tells me that you haven't really experimented with cardioids too much. Probably has some to do about
your preference of omnis. You need to find a great little onstage pull with cards and throw on the headphones and be set adrift.
Ahhh, here's one.
http://archive.org/details/ClubdElf2012-02-17.milab-vm44.flac16Lastly,(thinking out loud here), both omnis and cards obviously yield great stereo concert recordings. In order for me
to fully experience/appreciate what's capable because I don't have a great playback system, I believe headphones are a must for the stereo field becoming alive.
For about two years now 80% of playback of live tapes are through headphones for me. I love 'phones