I'd swear I've seen the answer to this question in this
newsgroup before, but if so, damn if I can conjure up the
right search terms to find it.

I'm doing three more sessions this coming week recording the
Baltimore Mandolin Quartet. I've been using a borrowed pair
of Schoeps CMC64 cardioid mics for these sessions.

I just bought a pair of Schoeps CMC641 supercardioids. I'd
like to put up the new CMC641s as well this week to check
them out, but I won't have time to do proper listening tests
(it would hardly be kosher for me to be experimenting on
the client's time).

I've been using the CMC64s in an X/Y configuration at
about 105-110 degrees. I was figuring on putting the CMC641s
in X/Y at 90 degrees, but back farther than the cardioids.
Is there a rough rule-of-thumb as to how much farther back
a pair of supercardioids should be to get approximately the
same ratio of direct-to-reflected sound as a pair of cardioids?

Hal Laurent
Baltimore