For education..... what was "Sound Tracker" ?

[guitar_199]

I know Cobras had models out in the past that had the moniker "Sound Tracker" on them.

What exactly was that? Was there any circuitry added to do anything? Or was it just marketing hype of some kind?

Thanks,
Bob

 

[w9cll]

I believe it was some sort of a compression system to increase the audio.

 

[ForestRunner98]

I believe it’s only “effective” if both radios had one and it was engaged. My previous radio had one...I couldn’t tell the difference.

 

[LeapFrog]

Thread:
https://www.worldwidedx.com/threads/cobra-25-wx-nw-st-lowering-the-deadkey-question.211315

JoeDirt,
for a "compander" arrangement to work correctly, both the receiving and the transmitting station should be equipped with the technology.
This tech was actually developed for the telephone industry, but made it's way into the two way radio world. Secret CB tried to sell a kit that was basically the same thing as the sound tracker technology, and they called it the "Voice Signal Booster 1" or "VSB1". you can read about it in volumes around 7-10.

the transmitting station's signal is compressed, and then the receiving station expands the compressed signal.

obviously the radios will work whether the other station has the tech or not, but the tech won't be helpful in those situations, and some say it actually makes things worse than if neither radio had it.

i will see if i can find some of Cobra's old literature from back when they thought it would work well. LOL
LC

 

[undertaker]

Lucky for me mine is not the sound tracker

 

[w9cll]

Cobra today is not the Cobra of old, most of their stuff is junk now. Their offices are just a few !miles from me, someday I should stop in.

 

[secret squirrel]

I thought it was a device used in the Man from UNCLE, by UNCLE agents. "Open Channel D."

 

[144inBama]

I believe it’s only “effective” if both radios had one and it was engaged. My previous radio had one...I couldn’t tell the difference.

Correct, I had a 29 ST and I couldn't tell the difference unless the other guy had it, in which case, it sounded awesomely clean and clear compared to it not being engaged. It's been a long while ago but I believe at distance, it even pulled in better, signal was obviously the same but the voice was better heard.

 

[Handy Andy]

Man I feel old, we had things like dbX Dolby HX, Quadraphonic, Omnisonic imagers - all kinds of compression/Expansion technology for the effort of reducing the noise from the transfers' of Recordings to tape or other mediums that had inherited traits for noise floor problems Noise gates are about as close as you can come to understanding that.

The effort the technology did back then was more or less "transparent" to the end user if they did not have the proper equipment you still could enjoy much of the sounds and music of those recorded efforts - but without the proper de or pre emphasis equipment - you couldn't truly enjoy the effects of microphone placements and how the studio engineers put together such an effort.

It's although overdone now, the effort of Pink Floyds' Dark Side Of The Moon album as well as Billy Thorpes' Children Of The Sun - cheesy by todays standards but definitely a lot of the effects embedded in the tracks could be brought out by using that equipment.

 

[w9cll]

It's although overdone now, the effort of Pink Floyds' Dark Side Of The Moon album as well as Billy Thorpes' Children Of The Sun - cheesy by todays standards but definitely a lot of the effects embedded in the tracks could be brought out by using that equipment.

You have this right, first time I listened to dark side with headphones was a little freaky. I played with quad back inn the day, it was bitc h to setup but sounded cool.

 

[ForestRunner98]

In the late 80’s the Griffith park observatory in the Hollywood hills had a lasereum. On Friday and Saturday nights they would play Dark side of the moon or Zepplin 4. Total trip experience!! Get stoned in the parking lot and go in and experience lights and loud stereo sound. Good times!!!

 

[Handy Andy]

Well.- for what it's worth, heres the Cobra 18ST rendition of the Sound Tracker system.

​

So in a way, for you to enjoy the ST effect, you had to have a separate radio listening into it to understand the effect.

Others that didn't have the ST feature, got the noisy reception but also could hear the extra compressed effects of the audio in the signal from that ST-radio..

Examples would be - when ST is turned off, they are typical radios, when it was on, the compressor side added more to the audio by compressing it into a higher energy level signal within the carrier that others could hear this as an extra level of like they turned up the mic a bit more.

On the ST based units listening in, when ST turned on, the noise floor of the ambient air noise at the re3ceiver side, got quieter because the receiver can engage the expander side of the Compandor and push down noise that would otherwise washed in with the signal.

The ST radio used a little trick to accomplish this, they added extra amplification to the Expander input to obtain this compressed signal and then expand it's dynamic range to normal

Note the Yellow Arrow, points to a R802 and C816 ...​

That simple little amp took in the channel - all it's noise after the ANL did it's effort to reduce the noise - then this little amp simply amplified the signal left from the previous processing and injected it into the EXP (Expander) input.

But notice the novel use of R802, and C816 - these two act as a tonal amplifier filter (parallel) - so the Compressed effects of the ST unit, can then be more amplified using this tonal filter.

So with many looking into HI-FI and direct inject, many are not hearing the "expected" levels of distortion that normally come with radio reception. There is better fidelity, but lack of intelligibility - because too much is placed on bandwidth and not the inflection and distortion products that helps us discern the consonants from the vowels and when you listen carefully, your phone call does about the same thing - only uses less that 8-bit DAC (255 different tone burst effects) using the VOIP compression technology already in your Cell phone.

 

[Cabover Bob]

[QUOTE="Handy Andy, post: as well as Billy Thorpes' Children Of The Sun - cheesy by todays standards[/QUOTE] - and I thought that me and a couple high school buddies were the only ones that listened to that jam, good times 4 sure........

 

[guitar_199]

YOU KNOW "Children of the Sun"???

 

[Cabover Bob]

YOU KNOW "Children of the Sun"???

Makes three of us.......