[Elecraft] KX1 headphones

[Mike Morrow]

>I would not have spent the money on my Etymotics just for listening to  
>CW, but since they are great for listening to music with great fidelity
>while traveling on planes, which is something I do a lot of, I look at it
>as a bonus that they will be nice to use in conjunction with my KX-1
>once I build it. 

The absolute worst thing one can have in a speaker or headphones for
communications use is "high fidelity" and broad frequency response!!!

Communications-quality audio devices are deliberately *designed* for limited
frequency response (typically about 300 to 3000 Hz).  Anything of higher 
"fidelity" is adverse to quality in a communications device.

One might as well eliminate receiver IF and front-end filtering if high
fidelity is the goal.  But, of course, high fidelity is not the goal.   Just as
receiver IFs with limited bandpass are desirable, especially for CW
communications, so are headphones with narrow frequency response.
Narrow frequency response helps eliminate undesired signals as surely
as that IF filter.  And since the front-end and IF filtering in the KX-1 is
limited, hi-fi entertainment headsets are the last thing one needs.

QRP rig designers usually provide a headphone jack that accepts the common
entertainment-quality headphones with stereo connections.  That seems to
encourage the use of these unsatisfactory entertainment audio devices,
whether they be $5 Walmart specials or much worse, those wildly overpriced
"specialty" hi-fi headsets.

The best earbuds for communications use that I've ever found are Kenwood
HS-7 mono earbuds, with the essential limited frequency response. 
Unfortunately they haven't been available for more than a decade.

If you have headsets that are spec'd for entertainment audio purposes, that
should immediately be a warning that they are far from optimal for communications 
use unless nothing else is available.

Mike / KK5F