1. Re: Decca Tree?

["Greg Simmons" simmosonics]

--- In  Dan Dugan <> wrote:

> John Lundsten's correction is acknowledged. To amplify:
>
> Adding two identical signals in phase increases the level by 6 dB.
But
> subtracting two identical signals nulls!

Yes... I don't know what I was thinking when I wrote 12dB, come to
think of it. It is at odds with the mathematical explanation I had
given in an earlier post.

But 'infinite' is the correct theory and, as John pointed, in practice
we get less than infinite. For example, DPA's 4011 (a fine example of a
cardioid) has about 28dB of rear rejection at 1kHz, and just over 30dB
at 2kHz. For many practical purposes, that may as well be infinite.

- Greg Simmons