"Deek" wrote in message
. ..
Telstar Electronics wrote:

On Sep 13, 3:19 pm, Deek wrote:

Telstar Electronics wrote:

Why Do You Need a Speech Processor for Your CB Radio?
Two-way radio communication relies on the modulation contained within
the signal. Maintaining a high modulation level is crucial in
providing the highest possible efficiency from any transmitter
operating on AM, FM, or SSB modes. Two-way radios also rely on
microphones that inherently change audio levels delivered to the
transmitter. This causes transmitter modulation to fluctuate greatly
depending on voice level and pitch. The average modulation of a
typical voice signal is only about 40%. This low percentage applied
to the transmitter, results in less than optimal transmission range.

PURE B--- S---

The peak power is the peak power is the peak power!

Distorting the audio with a speech processor ... distorts the audio.

Distorted audio is distorted audio is distorted audio.

Modulation is supposed to fluctuate greatly. It is supposed to replicate
your
voice which fluctuates greatly. If it does not replicate your voice it is
by
definition DISTORTION!!

Most processors cause 'nasal' and high pitched sounding audio because our
voices
are not 'nasal or high pitched. It is called DISTORTION.



You might want to read this... it's a good explanation of what
VoiceMax is all about.
http://en.wikipedia.org/wiki/VOGAD

I understand DISTORTION quite well! I hold an EE degree, managed an EE
design department for 10 years, and served as Chief Engineer on a major
Military System LGM 118A RS/RV.

Speech compression IS IS IS distortion. PERIOD!


You are correct, of course. But there are instances where distortion
increases intelligibility. as I'm sure an EE knows in spades.

Ed, NM2K

Ed Cregger wrote:

SNIPPED

You are correct, of course. But there are instances where distortion
increases intelligibility. as I'm sure an EE knows in spades.

Ed, NM2K



Ed, of course you are correct. The problem with CB compressors and the folks who
use them is that they don't know or pay attention to the reasonable limits.

My oldest son owns and runs an interstate long haul trucking business. I have
heard more garbage on 27.185 MHz from over compressed, over powered, over
distorted, off frequency, boosted radios while riding shotgun with him than I
care to recall.

Most audio 'power' is in the lower portion of the voice spectrum. Increasing the
mid range by 2 to 4 dB, adding 2 to 4 dB of audio spectral distortion, does
increase received intelligibility AND it does sound un-natural. Also, increasing
the average audio power output from 30% duty cycle to 50 or 60% audio power
output increases the thermal load on the PA final and heat sink by 100% in SSB
and by approximately 40-50% in AM. I don't believe CB rigs have thermal designs
for the heavier duty cycle.

When I chase DX on the ham bands I do not use compression. My transmitted audio
passband is 300 to 2400 Hz [IC 756 P3]. I have four HF radios [IC756P3, IC746,
IC706MKIIg, and KW TS570D] all with built in compression capability.

If I can't work them on SSB I do it the easiest way possible ... CW [Don't need
compression on CW] :-)

I have heard so many over-compressed signals on 75 and 20 meters that I'll turn
on two meters and join a local rag chew or round table where we old farts solve
all the world's problems.

"Deek" wrote in message
...
Ed Cregger wrote:

SNIPPED

You are correct, of course. But there are instances where distortion
increases intelligibility. as I'm sure an EE knows in spades.

Ed, NM2K

Ed, of course you are correct. The problem with CB compressors and the
folks who use them is that they don't know or pay attention to the
reasonable limits.

My oldest son owns and runs an interstate long haul trucking business. I
have heard more garbage on 27.185 MHz from over compressed, over powered,
over distorted, off frequency, boosted radios while riding shotgun with
him than I care to recall.

Most audio 'power' is in the lower portion of the voice spectrum.
Increasing the mid range by 2 to 4 dB, adding 2 to 4 dB of audio spectral
distortion, does increase received intelligibility AND it does sound
un-natural. Also, increasing the average audio power output from 30% duty
cycle to 50 or 60% audio power output increases the thermal load on the PA
final and heat sink by 100% in SSB and by approximately 40-50% in AM. I
don't believe CB rigs have thermal designs for the heavier duty cycle.

When I chase DX on the ham bands I do not use compression. My transmitted
audio passband is 300 to 2400 Hz [IC 756 P3]. I have four HF radios
[IC756P3, IC746, IC706MKIIg, and KW TS570D] all with built in compression
capability.

If I can't work them on SSB I do it the easiest way possible ... CW [Don't
need compression on CW] :-)

I have heard so many over-compressed signals on 75 and 20 meters that I'll
turn on two meters and join a local rag chew or round table where we old
farts solve all the world's problems.


-------------------

One of the things that I liked about some Yaesu radios (haven't used them
all to know) was that obtaining robust/strong audio with my bassy, soft
voice was as simple as turning up the mic gain a bit so that it was just
entering distortion. This trick even works on my FT-690R and used to work
quite well on my FT-726R as well. Getting my voice to project through any
radio has been a constant struggle.

Later on, with the advent of the IC-706, I was able to get good
intelligibility by shifting the "window" a bit through the crystal filters.
This is simply a matter of a software adjustment.

Like you, I do not use speech processors. They seem to be "tuned" for voices
that are a tad higher in frequency than my voice, so are completely counter
productive when engaged.

I have a Robyn 520D CB set from 1977 that is paired with an EF Johnson
ceramic element mic. No, it does not match at all, but it can make any male
voice sound like the God Thor when they talk. I keep it around just to
remember how far we have come. G

Ed, NM2K