If you ask 100 different hams what sounds good, you'll come
up with 50 different answers. Audio is a very subjective
thing, we don't all hear the same way.
Oh, what the heck, here are my opinions on this. Yours will differ.
A communications radio should provide the operator with audio
that is the most intelligible, so maximum information may be
extracted from the signal with the least chance for errors.
IMHO The last thing you want is high-fidelity extended frequency
range in your communications equipment. What is important
on receive is to accentuate the voice tones, that's from
about 150 to about 3000 Hz. Most of the energy is from 450
to 800 Hz-the, A,E,I,O and U sounds, the upper registers
tend to reproduce the constants, S, C and F sounds.
In the design of the speaker enclosure for voice or CW
resonance in the voice range is important, if music is
played through a properly designed communications speaker
it'll sound like a telephone call. The highs above 4 Khz
should be significantly attenuated.
Another important aspect is the compliance of the driver, or
sensitivity. So, how much magnetism does it take to push a
few ounces of cardboard back and forth? Not a great deal,
really. Speakers are rated in regards to efficiency by how
much sound they will make when given a standard signal level.
Contemporary tastes in hi-fi are to excentuate
the extreme lows and highs, suppressing midrange
frequencies. In addition to this consumers seem to feel
that as far as power goes, more is much better, so speakers
must be made less efficient to handle higher amplifier
powers consumers think they need. to do this magnets with
less power or gauss are used (although they are much larger-go
figure) and a wider gap from magnet to voice coil is used.
This effectively reduces the effect the electromagnetism has
pushing the voice coil and big heavy bass pounding speaker cone
around, as you can immagine control of the cone will be poor, but
it will thump well! The ability of a speaker of this design to
accurately reproduce a human voice or fast CW in an articulate
fashion is poor.
Lets get back to the human element here, yes, that. Many
people have hearing problems. Since one can't try on
another set of ears, we may not know what we are missing.
Many of my peers had their hearing ruined by attending extra
loud rock concerts in the 60's and 70's, our fathers may
have had their hearing ruined by exposure to artillery fire
or aircraft-fighting for our Country - kids now days?
Kicker boxes in cars? Oh GOD! Some of us may have special
needs and just not know it. The high end of hearing is the
first thing to go, there are devices that artificially
create extra high frequencies by clipping and filtering
lower frequencies. Indeed, this is creating gobs of
harmonic distortion in the upper registers. This effect
will drive a person with normal hearing up a wall, it sounds
extremely "Essey", but for an operator with lost high
frequency hearing, this process is a godsend for them. BTW,
the box that does this is called an Aphex Aural Exciter,
about $300 at your local music store. It'll bring a smile
to the face of the right people. This might be a hint Ten-
Tec.
Ten-Tec uses a small oval speaker that's not too bad when
it's mounted in the rig, but the same speaker in the power
supply seems to be less than ideal. I found placing some
glass wool around the back of the power supply speaker helps
greatly-or at least it did in my case.
For me, with normal hearing, an external speaker I have had
good luck with is the Auratone 5C Sound Cube. This is a 5"
speaker in a small cube shaped box, it's used in the music
recording industry as a "standard" car speaker example. You'll
see the little 5C along with huge Tanoy, JBL and UREI monitors
atop most mixing consoles in recording studios - to give the
recording engineer and producer an idea of how the mix will
sound in an auto with an AM radio and dash mounted speaker!
The Ten-Tec can drive it loud enough to get the XYL screaming
with it's little 1.5 watt amp. You get two to a box, parallel
them and get "stereo". ;-). Don't look for these at your local
ham radio store. You can get these at most professional sound
and recording stores.
As far as transmission audio goes, the Ten-Tec sounds pretty
good for what it's designed to do, it doesn't stand out-but
it's extremely clear. On my Omni I have found that the mic
processor adjustment is critical. In my Omni the 9 to 9:15
position does a great job fattening the audio, more adds a
great deal of distortion and picks up room tone, blower noise
and my metal chair squeaking. The meter is useless for setting this
"sweet spot" if the processor is driven to indicate in "the black"
it's too much - if you are going for a sweet sound. For DX I
run it up to the black - which gives a very processed sound
but really cuts through.
These are my thoughts on the subject, your mileage may vary,
don't try this at home, etc.
John
KE6PID
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