natural slap echo

[Haible Juergen]

	>I guess it depends on how you look at it...
	>The "receiver" has much higher gain...
	>and the Transmitter has focused all its "information" in a useful
direction...
	>So signal to noise is excellent...
	>BUT there is still less signal at the receiver than was
transmitted. The sound
	>can never be louder than the source...

Well, let me be picky here: The "sound" (pressure level) can surely be
louder,
while the total energy (of course) cannot be increased.

JH.