[Elecraft] Audio Output Impedance of the KX3

[Jim Brown]

On Mon,1/23/2017 12:54 PM, Jim Brown wrote:
> The impedance of mics is defined as 5X their minimum load impedance. 

Correction -- one-fifth of their minimum load impedance. For example, a 
250 ohm mic should drive an input impedance no lower than 1.25K. Most 
pro mics are in the range of 150-250 ohms.

Another point I forgot to mention. ALL electro-acoustic transducers 
(mics, loudspeakers, headphones) are very complex, and their equivalent 
circuits are also very complex, containing multiple reactive components 
and a few resonances. The impedance curve of a typical loudspeaker or 
headphone has a low frequency peak of hundreds of ohms, a broad minimum 
at the lower middle of its operating range, and rises rapidly with 
frequency as it approaches the top of its operating range. The impedance 
of a loudspeaker or headphones is defined as that minimum value of the 
impedance. Multi-way loudspeakers have two such drivers, each with its 
own equivalent circuit, fed respectively by low pass and high pass filters.

73, Jim K9YC