encoding (and decoding) 3 signals in to a stereo signal?

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12afael

Well-known member
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Aug 6, 2004
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I wonder if it can be done. with my band recently we have been rehearsing with a click track and some support tracks( keyboards mainly) . comonly to play live bands use a stereo track one side with the click and one with the support track then the drummer listen to the click and part of the support track and the PA is feed with the support track.  the problem is that the support track must be mono, provably fine for most of the aplications but what if I want to feed the PA with a stereo track? could it be done with some MS or other kind of encoders? this has been done before in other applications?

Best regards
Rafael
 
Not sure I understand the question, are you trying to multiplex L, R, and click,  into two tracks?  In general you want to keep the click well separate from any music.

You could experiment with a L+R (mono) and L-R (difference). If the L+R mono mix contains signals in it that can be used like a click track for timing (perhaps with extra EQ), then you can reconstruct the L and R signals  by summing  (L+R)+( L-R) =2L and (L+R)-(L-R)=2R 

JR

 
I'd use a portable 4-track recorder / playback device with 4 outputs.  You could use 1 & 2 for the backing, 3 for a click and 4 for a count-in for each song

Zoom, Tascam & etc make them. You just need to find one with 4 outputs.

Nick Froome
 
There is no linear relationship to with what I think you are trying to do, I mean, summing or extracting them, with gain scales and that's it. You can't have 3 independent tracks into 2 signals and recover them, if that where true we would only need 2 track recorders and then we can add a 3rd, and we still have 2, then we add a 4th, and still have 2 signals, and so on. There are other ways to do this, multiplexing is one, but you have to sacrifice at least half your bandwidth to fit 2 signals in one channel without perfect separation, as stereo FM for example, you multiplex M and S signals, and then you add as much S as you can split, and you have your stereo signal. Probably not good for your application since you would more likely to have the a single track for the click and another for the stereo, and you want the best for your stereo, with maximum separation from the click.

You could sacrifice a little bit less of bandwidth add a HF pulse, let's say a couple of 20kHz periods with a window so it doesn't introduce noise in a much lower band, then have a filter, at 16kHz so your signal from 16kHz and lower gets out and then you have a detector for the 20kHz which triggers a click from another place, a simple analog oscillator to do so, putting a pulse out, some eq/filtering and you have the click you want in an audible band, but your signal would be cut over 16kHz, if you do so in the S band you don't get stereo over 16kHz, which is probably fine for a live performance, you use stereo down there, and the M signal could have all high freq you want. Then for decoding you need a filter on the S, up to 16k you have your S, add and subtract from M to get L/R and over 16k at your S you use as a trigger for the click.

JS
 
you are right Joaquins, I was doing some maths and I have 3 variables and just 2 equations. sure I can extract the click signal but it is imposible to recover the original estereo track without the click.
multiplexing could be an option
 
I see a lot of bands do this with multitrack playback and an audio interface that has multiple outputs....

All the backing-tracks and click can then be summed or broken out depending on what the FOH/MON console(s) have available at the particular venue. Which can hopefully be prepared for accordingly if/when you advance the gig with the venue.

Ultimately, as you described, the drummer listens to the click and starts the playback when cue'd by the primary artist. He counts everyone in and the other musicians follow the drummer. Backing tracks are mixed through house/mon as needed and are "in time".

No need for encoding / multiplexing / de-coding multi-channel to stereo. Just need a laptop and an appropriate interface.

Hope that helps!
Cheers,
jb
 
Most bands that I've worked with run a small pro tools rig to do what you are going for.  Click is on one of the tracks, and backing tracks are sent out to two or more separate outputs. 
 
Unless you plan to play the tape at different speeds why does the click track need to be recorded?  If it's a sync thing, a click could be on the leader before the song starts.

JR
 
if by 2 track you mean analogue 2 track then fitting 3 or 4  in 2 is done with phase like Dolbysurround.
if you go digital you can have 6, 8 or more channels in a single stream but you need encoding and decoding
 
ubxf said:
if by 2 track you mean analogue 2 track then fitting 3 or 4  in 2 is done with phase like Dolbysurround.
if you go digital you can have 6, 8 or more channels in a single stream but you need encoding and decoding
Something like Dolby or CBS's old phase shift encoding will not give you 4 discrete output streams with acceptable separation to use one for a click track.  There will be enough click leakage into the other outputs to be unacceptable (IMO).

JR
 
JohnRoberts said:
Unless you plan to play the tape at different speeds why does the click track need to be recorded?  If it's a sync thing, a click could be on the leader before the song starts.

JR
Some drummers can't play if they don't have a click.
Listening to the other musicians? So old-fashioned, very unhip...
 
If you are trying to get in the track that isn't sounding still, or have a silent path, I see can be a big problem not having a click... The best option is the multitrack, an m-audio m-track are called the newer ones, but an older fast track should work as well, as any other brands, it's the one piping out right now since they are pretty good for the price, the lower cost decent ones I know, and you only need 4 outputs for your needs...

JS
 
abbey road d enfer said:
JohnRoberts said:
Unless you plan to play the tape at different speeds why does the click track need to be recorded?  If it's a sync thing, a click could be on the leader before the song starts.

JR
Some drummers can't play if they don't have a click.
Listening to the other musicians? So old-fashioned, very unhip...
I was suggesting that the click could be generated in real time and not wasting a precious track on the 2-tr recorder.

JR

PS: I suspect some can't play even with a click track...  :eek: Just kidding drummers, you know I love you all.
 
JohnRoberts said:
abbey road d enfer said:
Some drummers can't play if they don't have a click.
Listening to the other musicians? So old-fashioned, very unhip...
I was suggesting that the click could be generated in real time and not wasting a precious track on the 2-tr recorder.

PS: I suspect some can't play even with a click track...  :eek: Just kidding drummers, you know I love you all.
My secret sources tell me the next version of Resotune will not only tune your drums without human intervention ... but will play them for you.  Just hum the tune once and it does the rest.

Those of you unhappy with your drummer, send $$$ to https://www.resotune.com/ to be put on the waiting list  ;)
 
ricardo said:
JohnRoberts said:
abbey road d enfer said:
Some drummers can't play if they don't have a click.
Listening to the other musicians? So old-fashioned, very unhip...
I was suggesting that the click could be generated in real time and not wasting a precious track on the 2-tr recorder.

PS: I suspect some can't play even with a click track...  :eek: Just kidding drummers, you know I love you all.
My secret sources tell me the next version of Resotune will not only tune your drums without human intervention ... but will play them for you.  Just hum the tune once and it does the rest.

Those of you unhappy with your drummer, send $$$ to https://www.resotune.com/ to be put on the waiting list  ;)

No RESOTUNE will not tune drums by itself.. I could add a motor gadget to turn the lugs but you still need to have a plan and a clue. My customers think I'm already too expensive, so I'm not going to make it more expensive. .

I could make it click, but I'm not going to do that either... must be a dozen smart phone apps already.

JR
 

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