Yamaha mixer muffling my vocals.
November 1, 2010 9:53 PM   Subscribe

Mixer (Yamaha EMX 312 SC) is muffling the vocals. Awful sound. Help?

They installed two speakers (not sure what kind... they removed the logos/branding for some reason) as well as a mixer, TV and DVD player in the children's gym I'm in charge of. Part of our curriculum relies on music, specifically having the children follow the actions given in the lyrics of songs. So it's a bit of a problem we're having.

I feel like a dunce, because I've done a bit of audio work before in my past in the tv/film/live event industry... but alas, I cannot figure out the problem.

I've hooked the mixer up to my desktop computer, and no matter what I try to play (youtube files, iTunes, DVDs, etc) the sound comes out like an instrumental track... the vocals are almost completely gone. (whereas if I use headphones, it's perfect). The rest of the sound is good, if slightly muffled.

I've tried everything Google tells me to, with no result. My first class is this afternoon. Help?
posted by hasna to Technology (7 answers total)
Sounds like one of the channels is out of phase with the other. If this is happening only in the speakers, not headphones, it probably means one of the speakers is wired backwards.
posted by xil at 10:03 PM on November 1, 2010

Seconding what xil said. Reversing the phase of one of the channels and then combining the two into one channel is commonly used on karaoke systems as a quick-and-dirty way to remove vocals.
posted by zsazsa at 10:14 PM on November 1, 2010

Agreeing with the above, also, with installed systems like this, don't assume anything. Is there an EQ somewhere between the board and the speakers that you may not be seeing? Everything wired correctly? I've seen some things you wouldn't believe (incorrect pinouts, bad or no ground, reversed polarity) on installed systems that were supposedly done by professionals. If it's not something obvious, go back go basics. Plug in your headphones and monitor the channel(s) in question. Does it sound okay there? If so, look for something in between the board and the speakers. If not, double-check everything on the board.
posted by xedrik at 10:30 PM on November 1, 2010

Best answer: xil is likely correct. The easy test is to turn down one of the channels (either left or right) entirely or pan your sources hard left or hard right.

If everything sounds fine out of either channel (bot not out of both), then you need to figure out whether it's your speaker or your amp that's wired out of phase. (Actually, you don't need to figure out which is the problem; you just need to reverse the wiring of one or the other.)

If this doesn't work, then there's some sort of equalization problem or a (different) wiring mistake, but I would bet on the phase.
posted by JMOZ at 5:42 AM on November 2, 2010

Nthing that it's out of phase. You also probably have it set to mono instead of stereo.
posted by empath at 6:30 AM on November 2, 2010

Response by poster: late replying but... that was it! Thanks JMOZ!
posted by hasna at 5:11 AM on September 20, 2011

Ha! Glad to help.
posted by JMOZ at 2:20 PM on September 24, 2011

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