@Carambolooo You have forgotten to connect the right inlets of the [*~] volume controls for the effects channels.
Here is an abstraction that will give you the [panner] objects........ panner.pd
Put it in the same folder as your patch, then re-open your patch and for each instance give it an argument.
...... so in your patch change each [panner] to [panner 1] [panner 2] etc.....
That will keep them separate..... each one will receive control messages from only the fader that you wish.
Look inside [panner]. You will see at the top [r pan$1]. The $1 will take the argument you have just added to each [panner] as it is created.
Before you continue you should get to grips with abstractions...... that will save you a lot of time as you develop your patches......... https://forum.pdpatchrepo.info/topic/9774/pure-data-noob
You need to change all the hsliders controlling the pan to have a range of 0 to 1
In fact all your sliders need to have a range of 0 to 1 (because audio values in Pd must be in that range) and you will have to change them all in their properties pop up window..
You might well need to reduce the volume after your [catch~] objects as well because adding lots of [throw~] sends together will give you a final output greater than 1.
As @benalb says...... we have no "multiply defined" problems in Pd.
My best guess is that you have opened your patch twice..... effectively having each [catch~] then created twice in the plugdata program.
David.
Ps.... other parts of your patch could also be abstractions...... e.g.
You would create an abstraction...... say [mymix] and give that the argument for the channel number..... [mymix 5] etc.
Inside it would look like this......
..... and [panner $1] would then get the same argument (5 in this case) from its parent abstraction.... its a sort of magic......
And adding a $0 to all the send and receive names would mean that you can open your [mixer] twice without cross communication and without any "multiply defined" errors.
You could even include the control faders and VU's and show them through the GOP window of the abstraction...... another subject, but see the link above.......
Expanding your patch would then be child's play rather than a lengthy process prone to errors.
It's a lot to learn in one hit..... but well worth the effort...