Hi Guys,Tomorrow, I'm going to have an event using 12 boxes of nexo geo s12 and 4 boxes of rs18. Just now we did some line check in the venue and we found some problem when we did some phasecheck. In the GeoS12, the right speakers are all green, which is normal polarity. But the left speakers are all red, which is inversed polarity.The same thing happened when we did some phase check in the RS sub, but this one is more random, because one sub has the "red" light on the left speaker and "green" light on the right speaker, and other sub has other way around.However, when I tried to play music from FOH, everything just sounds normal.I was trying to find the setups in the NXAMP but didn't find any clue in it. Could it be because of the cables? Any idea?Thanks a lotRegards,Dion
What is your procedure for this "phasecheck"?
It sounds like you have at least one cable with the polarity of the + and - signals reversed. I would recommend checking all your cables and your snake's input channels and drive lines to verify that they are all wired correctly. Then, check all the cabling in the racks to make sure all those cables are correctly terminated.
I am using a toolkit called "phase checker". Then, I played a music that only contains kick drums infinitely.While doing that, I hover the phase-checker close to the speaker and it will show either "red" or "green" light. Not sure what you call it in your area, but in my home country they call it a "phase checker"..I have re-check all the cables couple times, and it seems everything is wired correctly. I will try to buy the new cables this morning and replace them all. Just in case, if my old cables are not functioning well anymore.. Thanks a lot for your suggestions
Dion, Because I don't know how adequate your measuring method is: How does the rig sound with music? If all of the boxes on one side are out of polarity, it should be very, very noticeable. Stand in the middle of the room where the Left and Right signals intersect. Anything panned center should be reduced greatly at that position, i.e. lead vocal. If you still have a problem check 1) Settings, and then 2) Cables. JPIf you are still measuring, Turn off the left side when measuring the right side, and measure each box individually.
It is NOT a "phase" checker-but a POLARITY checker-BIG difference.You say you checked the cables. Does that mean you removed the shells and actually looked at the wiring INSIDE the connectors?That would be a first step.Or maybe the first step would be to make sure that you don't have the POLARITY reversed in your console-DSP etc.
Hello, thanks JP for the suggestions.I've just finished with that event now. Too bad I didn't have time to re-do the cables at that time, but everything sounds normal. I didn't notice any differences in every corner. I was lucky because it's just a regular wedding event, so it didn't require high level of output. But for the next event, I will try to do your suggestion as well. Thanks a lot Hi Ivan, Yes, I have checked all the cables inside, the wiring are all correct. About the reversing polarity in the console, this probably still becomes big question for me.I am still a new user of NXAMP 4x4 amp and when I tried to find settings that related to polarity setup, I couldn't find any clue in it. I'm still trying to contact the NEXO technical support about this though.Thanks anyway
Troubleshooting 101 Divide and conquerSwap things around and see what happens. If you are running stereo-swap the outputs of the console and see if the problem follows or stays the same.Then swap output of DSP-does it change? And so forth
Dion,“Phase Checkers” results can sometimes be a little confusing and inaccurate. It is quite possible that all is well, other than the results the phase checker is giving you. They detect whether a pulse produces a positive or negative pressure, and there are a few tricks when using them. Measuring near the port of a reflex enclosure, have the speaker near a boundary, clipping the measurement mic, using a pulse that is of the incorrect frequency, background noise or other speakers in the array can all cause problems. As a simple check I would start with one sub, then connect another, if it gets louder it’s “in phase” (polarity)… and so on.
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