[Elecraft] Nearfield monitors

[Erik Basilier]

Don Wilhelm wrote:

 

"Any radio will show its true audio traits if it is fed into a good
wide-range speaker (or amplifiers and speakers)."

 

I strongly agree, but theoretically a speaker with an intentionally limited
response (as opposed to a cheap speaker) can to some extent cover up some
problems in the radio's audio as revealed by the good wide-range speaker.

 

What I haven't seen mentioned in this discussion is that if you want a good
wide-range speaker, e.g. for critical examination of your radio, or for
permanent use if the radio has good audio, it is not enough to buy some
specific speaker known for good quality. Any given speaker can vary
enormously in its response curve depending on how it is placed in relation
to walls and other equipment. It is not enough to follow some instruction
sheet that came with the speaker. I find that with quality speakers it is
necessary to perform some kind of response measurement during installation.
This is not as straightforward as it may seem. Even good speakers tend to
have response variations with frequency, but if you look at measured
response diagrams, they are for anechoic chambers. In practical
installations you will encounter all kinds of room resonances that cause
bumpiness even with the best speakers. The objective then cannot be flat
response, but a flat average response over limited frequency ranges, and
balance between those ranges. My favorite way of testing for that is to use
a series of warbling test tones, each of which covers a limited range of
different frequencies, as produced by an old test CD I have (disques PIERRE
VERANY PV 784031 CA 803 "DEMONSTRATIONS TESTS"). On the detection side I use
a cheap RS sound level meter. It is not perfect for the highest audible
range, but the room resonances happen mostly at the lower frequencies
anyway. You get an average reading during the warbling, and this is much
faster than measuring at high numbers of individual frequencies. Warning:
when you have moved the speakers for the flattest possible response, they
are not likely to be where you would like them from a decorator's point of
view!

 

73,

Erik K7TV