When you view Stereo as Two Mono channels, where do things go right or wrong? if any...
thanks!

 

I see two mono channels as two narrow spaces separated and with no communication between them, while a stereo channel is a more wide space and the elements can move from one side to the other and interact with each other. Sort of...

 

if you want an answer you should ask a question.

 

One goes right, one goes left.

 

the term Joint Stereo was used long ago for audio broadcasting because of smaller amount of data. All the non internet radio still uses this right ? (not sure, forgot the last time doing that, who listens to that kind of radio now anyway) Especially the audio player inside a car, whenever you tune in to the radio a small "stereo" sign appear when you get the broadcast in full reception. I thought this is old tech, no ?

 

Wut?

 

what goes up, must come down!

 

joint stereo is when you write both channels in the same document.

 

It goes "right" when you get what you want from the majority of playback scenarios you are targeting. It goes wrong if you signal has phase issues on playback, or other wonky shit is going on if summed (stereo files might be summed if the playback system is mono.)

Joint Stereo encoding isn't quit the same thing as M/S || L/V though they share similarities. Any audio can be represented as summed center (mono sum) and the difference L-R which results in L C R. This is just mathematical representation and there is no loss of fidelity. Encoding as LCR doesn't really save that much space and you can reconstruct L/R PCM with no fidelity loss. Joint implies L+R (L(-)/R(+)) for encoding purposes you can lower the bitrate in the mids and filter lower frequencies out of (L-R) and algebraically reconstruct the inverse channel as present in (L+R). all post filter as you generally can band limit the entire signal bellow full range.

Broadcast FM Stereo did use a version of JS, not to save data (actually bandwidth) the system actually used more bandwidth but before there were computers FM composite multiplex signal scheme allowed analog FM decoders to be mono or stereo without needing any type of summing bus. There are 3 principles tones in an FM Stereo broadcast

• L+R (mono sum) from 30Hz-15KHz
• L-R (vertical differences) 30Hz-15KHz - double side-band switching suppressed carrier encoded from 23 kHz to 53 kH
• 19Khz Maximum Amplitude Pilot tone - signal lock / phase alignment for L(-) R(+) @38Khz AM sub carrier.

The FCC chose this method as a monaural receivers that people already owned would continue to work regardless of weather the station broadcast in stereo or mono.

This era where the term Radio Ready first came into the lexicon before it was a shyster term for compress the shit out of music. If you had phase issues in summing the L+R sum would be attenuated or even harmonically comb filtered due the nature of non-linear analog stereo decoders and signal drift.

It's been a long time and all this is from memory so check on it and I don't really remember the formulas off the top of my head but I am sure they are out there in the intrawebs.

yup

 

Last edited: Mar 9, 2021

Thank you for this. This is new information.

 

This is one thing I like about soundforge. It will take a stereo track which is two mono tracks, L&R and allow you to deal with the left and the right independently. I don't think audacity for example allows independently working with the two parts like this. Being able to mute one side and just hear the other lets you hear what is included in each side, and might give insight into how they interact with one another to create stereo imagery. Not sure if this addresses your needs but it does tend to give you insight to be able to isolate them in this manner.

 

You are welcome. Happy to be of some assistance.

 

why is it that in hifi gear left is white and right is red?
does it have anything to do with politics?
With racial discrimination?
it would be better the same color for both channels so to give them equal opportunity

 

Last edited by a moderator: Mar 10, 2021