[Les.]

"Martin Griffith" wrote in message
...
On Sat, 3 May 2008 17:01:19 +0100, in sci.electronics.design Ian
Jackson wrote:

600 ohms is dead and buried, for the audio world.The only time it is
mentioned is in data sheets, "will drive XXdB into 600R" etc


martin

Quite so. The concept of matching a microphone's impedance to get the best
power transfer has not been practiced for a considerable time.
Modern dynamic mics expect to look at a "bridging" impedance e.g. around 10K
for a mic having a Z of 150-200 Ohms and to operate as a voltage, rather
than a power source.
The characteristic imedance of the feeder (over a few feet) may thus be
disregarded.


Les.