On Fri, 18 Nov 2005 20:45:27 -0600, Charlie
wrote:

Instead of paying $75 - $150 for an adapter, I constructed
what is the equivalent of 500 ohm source impedance to
4 ohm (actually, 2 8-ohm earbuds in parallel) adapter.

Is your intercom/radio capable of enough signal level (voltage, not
current) to compensate for the ~100-1 stepdown in voltage?

he has ~100:1 impedence ratio ... that will be about a 10:1 turns
ratio ... impedence in an n^2 relationship.

Question is still valid, though. The POWER, less efficiency, will be
the same, so 1mW at (say 400 ohm) will be 1mW at 4 ohm. So if the
sensitivity of the transducer elements is the same, same SPL.