This is SOUND advice :*) BUT I've played around with speakers for
years. CW confronts us cw ops with some demanding requirements that no
off-the-shelf stereo speaker offers. First, the speaker must be
"sensitive". That is, it should not require much power for full output.
Most stereo speakers have foam cones and heavy magnets. These are fine
if you have 15 or more watts to drive them but with the wimpy amplifiers
in our rigs you should expect full output from only 1/2 watt or so.
Otherwise, you will need to crank up the volume into the distortion
range.
Next, the speaker should have absolutely no bass response. The low end
cuttoff frequency should be around 500hz. Most stereo speakers, even
cheap ones cut off at about 60hz. Good bass response is fine for rap
music but with cw, it punctuates the thumps and clicks. This is
especially bad for qsk work not to mention how it enhances the sound of
static.
Furthermore, the cw-man's speaker should roll off at the high end at
around 1000hz. Most store-bought speakers roll off at about 16,000hz
which results in audible white noise generated within the rf and IF
amplifiers.
The MFJ ClearTone Speaker Model MFJ-281 meets all the requirements plus
one other. It resonates at about 700hz which is perfect for cw work. I
can turn the volume all the way down on my Omni V and still hear cw! Of
the hundreds of speakers I've tried over the years, nothing comes close
to such accurate reproduction as this little spkr. The cone is a made
from clear mylar, a stiff plastic like substance. This would be terrible
for rock music but perfect for cw!
My last point is that the case plays an important roll in the speaker's
operation. The case works together with the speaker to produce a
resonant system at 700hz. If the speaker is removed and placed in a
power supply, loudness will suffer and it will no longer resonate at the
proper frequency. Yes, anything is an improvement over TenTec's internal
speaker but don't be to anxious to perform a speakeronomy in hopes of
better sound! Spend the $10 and enjoy some easy listening.
Steve N4LQ
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