I need a bit of guidance from those of you who understand the complex technical details of signal processing.
I have a send from my Alto 1604 going to my Lexicon PCM81. The send is a single output but the PCM81 receives input in stereo returns in stereo.
Reading the PCM manual (an online version and a hardcopy with the unit), it suggests using a Y cable to run the single output to both L and R inputs. I am doing this but the input to the PCM is only coming in on one of the channels, not both. The online version of the manual also says to use a Y cable for the outputs of the unit to sum the return to mono. The hardcopy does not say this.
My query is:
Why is the Y cable not splitting the signal from the send? I have tried 2 separate Y cables - same outcome for both.
Should a Y cable be used for output? Will that not create a mono unit out of my PCM?
I’ve searched this topic on the net and found others querying the same problem - all suggest a Y cable in line with the manual - Have I got the wrong cable (picture attached)?
you probably have a balanced send(mono) on a TRS jack and a Y cable which is a splitter i.e. T and R go to different sides - either way the send can probably be a TS(mono) or TRS(mono), so use a TS which is shared to two other TS jacks or try a Mono TS patch cable into your female Y from the mixer send - or configure the rack to work in mono if possible
Plug a mono patch cable (TS) into that adaptor - now see if both male outlets are getting the patch cable signal - use any device - there isn’t enough info on that screen grab to know - the colouring implies a shared signal - but you can test to be sure
unless you have an unusual mixer with stereo tracks and an unbalanced stereo send on one TRS then that will be a mono send and it is probably fine to use unbalanced TS although the manual asks for TRS
you could see if there’s a way to find a TRS to dual(i.e. copied) TRS if you have to preserve the balanced signal for some reason
Maybe I’m misunderstanding, but many rack effects that accept stereo also accept mono only (usually marked (L/Mono) so if all you’re doing is sending a dual mono signal and then summing the stereo output from the effect, all of this stereo stuff is pointless. Maybe worse than pointless, you could get some phase cancellation depending on which effect is being summed to mono. Why not just run the mono send from the mixer into one input channel of the effect, and a mono return from one output channel of the effect to the mixer’s Aux Return input? Or, if you want the stereo effect that some units provide (ping-pong delays or anything like that) you don’t have to use the Aux Return inputs, you can bring the stereo signal from the effect into any of the stereo inputs on the mixer. You would still only need to run a mono signal to the effect itself. I don’t know that particular unit though, maybe if it is given a signal on the left or right output only, it will only give a signal from the left or right output respectively. If that’s the case, and each side of the effect is being processed separately in true stereo, then running dual mono split to it from the mixer is once again pointless since the stereo outputs of the effect will give an identical signal and you’d be better off just using a mono send/mono return.
edit: Just looked the Lexicon up, looks like quite a nice unit and it looks to be true stereo processing. I still think that sending a dual mono signal to the unit, and then summing the stereo outputs to mono again for return to the mixer is totally pointless. Better to use it in stereo for real, or just use one side of the effect.
If you’re feeding it identical mono signals? I have effect units that will give a stereo effect from the stereo outputs even when feeding a mono signal, so in that case it is still useful to use the stereo output (for effects like ping pong delay, reverb with one side delayed, etc where a stereo signal is being created from a mono input like I said in my post above). My point is that it’s pointless to feed a dual mono signal in that case, unless the unit will only output a signal from the side it’s given a signal on. I covered that in my initial post. I think you misunderstand what I’m saying.
Looking at the manual for the Lexicon, it says that a mono input must be split between the 2 stereo inputs using a “Y Cable”. My mixer send is a single output which leads to this situation. Apparently, according to the manual, the Y cable sorts this out. I think me using the wrong cable has been the issue.
I await the delivery from Amazon to hopefully move beyond this current obstacle.
Ok gotcha, so if you split the mono send from your mixer and send it to both L/R inputs on the Lex as the manual says, then you should return the stereo signal to a stereo input on the mixer rather than summing the stereo output from the Lex and returning it to the Aux Return on the mixer. If you sum the output from the Lex, you might as well just use a single channel of the the Lex to begin with.
Could I use the subgroups as a stereo send?
I can assign different channels of the mixer to different subgroups. Each subgroup has the same type of out as the send. If I used 2 subgroups, one with a lead to the left input of the PCM81 and one with a lead to the right, would that work?
Could I then simply assign channels to these subgroups?
Oh yeah the ring side wouldn’t be sending, you could just get the Elektron CV kit to send dual tip. Or, if you’re handy, just clip the TRS jack on that cable you got and solder up a new jack with both sides connected to tip. Or, you could just use two aux sends. Also, I just looked up the mixer you’re using and it looks like you have four (!!!) stereo aux returns so you should definitely use those.
