hi!
a few things,
-a y cable can NEVER sum signals, only split them
-I assume your acoustic has piezo pickups on it? In this case you will need an unbalanced/mono TS cable. These cables have only two conductors and will only work for mono signal. You can differentiate this type of cable from a TRS by the fact that the connectors have only one band around them, rather than two (http://content.answcdn.com/main/content
E/TRRS.GIF).
-For your gameboy, you need to send a stereo signal. This means using a 1/8th TRS cable capable of sending a stereo signal. These connectors use the same system of bands to differentiate themselves, so in your case you'd be looking for a connector with two bands, just like a headphone connector.
-A mixer like the xenyx which you could use to sum your signals will only have mono inputs. This means you will need to split the two Left and Right channels of signal that your gameboy is sending from your jack. A cable like this: http://www.amazon.com/Hosa-CMP153-Cable
000068O3C) would be wired for this already. In this case the white end of the cable would go to the input labeled L on your stereo channel and red end to R (either channel strip 2/3 or 4/5 on the xenyx). Your guitar could just go to the first TS input on the mixer.
-Unless you pan your channels, you can just send one TS cable from either the L or R Main Out to the engineer. This will give him control of your overall level, but you will have control over the balance between your acoustic and gameboy. practice a little with the setup beforehand, so you can have a general idea of what your mix will look and sound like.
-I'm not sure what the open mic setup looks like, but if there aren't PA's available you can just send your mix out to a guitar amp. That being said if there are PA's set up already it's a better idea to just send your mix out to the engineer so he/she can set you at an appropriate level and mix to your vocals if you have any
sorry if that was longwinded or came off as condescending! I hope it was helpful and good luck on your gig
Last edited by Fudgers (Mar 11, 2014 6:28 pm)