[Elecraft] audio amplifier/speaker/headphone impedance matching

[Bob Lewis (AA4PB)]

> If the resistor is pure R and no X, it should have
> no effect on frequency response.

But the headset has X which means it represents a lower impedance at
lower frequencies. There could be more drop across the resistor at
lower freqs than at higher frequencies and that could affect the
frequency response. As a practical matter the difference in response
is probably not enough to notice.