QLab to Presonus issue...cue won't play even with signal

[Sayen]

We're running QLab off of a Macbook, and all but one cue seems to run fine through a Presonus 16.0.2. The cue runs fine through the Macbook speaker, but is silent through the mixer, and the input is a standard aux cable. The input meter on the mixer shows the same signal level for the bad cue as it does for ones that work fine, and everything is being outputted as a mono signal...so I'm stumped. I know the signal is reaching the board, I just can't figure out why that one cue won't output. Any thoughts?

 

[FMEng]

That one stereo file has one channel with reversed polarity, which causes a mono-sum to cancel. There are at least two ways to resolve it. The easiest would be to only use a single channel from the computer for playback. Or, open the bad file in a sound editor and flip the polarity of one channel. (Some will incorrectly use the term "phase" instead of "polarity.")

 

[Evans Poulos]

Just hit it with your sonic screwdriver!

 

[Amiers]

Sounds like a corrupted file. I would rebuild the file.

 

[TimmyP1955]

My guess is that you are running a 1/8" TRS from the laptop to a 1/4" TRS to the mixer. As such, you are running a stereo out to a balanced in, which means that anything panned to the center will completely cancel. You need a 1/8" TRS to dual 1/4" TS cable.