Karaoke Forums

This one is TOTALLY beyond me. First, when I set everything up (early in the day), did an equipment check, and noticed a hum in my speakers, jukebox on, but volume down. So..., when I went in last night, I brought some 3 prong to 2 prong adapters (just in case). Well, when I got there the jukebox is playing, it is one of the newer ones, and is hooked up to Bose speakers all around the ceiling. One place that has Bose speakers is in each corner (this may be of interest). So..., jukebox is playing, I figure I'll check for the hum in my speakers (JBL Eon G2's Active Speakers). I turn on one speaker, and the JUKEBOX is playing through MY speaker. So...., I go to the other speaker, turn it on and the JUKEBOX is playing through THAT speaker also!! By this time, I KNOW that I'm NUTS, this CAN'T BE, CAN IT???? I mean, there is NO WAY that the jukebox can be playing through MY speakers. The only thing hooked to the venue is the POWER cord. When the jukebox was turned off, the music went away, AND so did the hum. So..., what do you think of this? Any ideas, could the sound from the speakers (behind) my speakers (in the corners) SOMEHOW make the sound come through MY speakers? Weirdest thing I've ever seen. What do you think???

Rosario

sharing a tv or monitor in any way(tied into the sound system).....cable signal will also cause hum, so when sharing a video source you must cut off cable signal with a game switch or by unhooking the cable.

Are the bose speakers hard wired to the jukebox?
If the jukebox is transmitting to them you will pick some of it up.

by chance was one of your microphones turned on while all of this was happening?

Just a shot in the dark.

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FlipSide Karaoke
Scott

Actually, my mixer wasn't even turned on, and as I said, I wasn't hooked into the house system, except for the power cord into the electrical outlet. REALLY WEIRD.

Rosario

Elementary mate.
They are picking up a transmission.

Hmm,,, did you see any strange lights in the sky and some really short "odd" looking fellows there last night?? ,, just giving ya a rash of crap!!!

Now that I come to think of it, I DID see some lights flashing in the window, but I just thought it was from the colored disco balls. Ok, Johnny, that's your cue, I know you can't resist that line!!!

Rosario

My best guess is that somehow the signals were somehow linked in the electrical system. I would try a different power circuit and see if it still happens.

Another possibility is that the bar tapped into your speakers IF you installed them. I installed speakers in one of my bars and the owner asked me if he could hook his jukebox into it. I told him for the price I would charge over the course of a year, he might as well buy his own (which he did).

are the bose speakers powered speakers? or running a 70v line?
could be that who ever installed them ran the speaker wires right next to the power wires and it is cross feeding into the power lines which your speakers are picking up.

Don't know how the house speakers are wired so it makes it a little difficult to diagnose.

If the jukebox power box is wired wrong it could be feeding back into the ground somehow. Get yourself a receptacle circuit tester to make sure that the plugs are wired correctly.

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I like everyone when I first meet them. If you don't like me that's not my problem it's YOURS!
A stranger is a friend you haven't met yet

I'm really not going to worry about it, was just curious as to how this could happen. I have no idea how the place is wired, or who wired it. When the jukebox was turned off, everything was fine.

Rosario

Inductance is a wonderful thing! google it and i'm guessing you will find your answer.

I've heard of powered speakers picking up random interference.. especially in buildings with bad ground or plug polarity issues. Due to their design (as light weight as possible, sitting up in the air on poles) they tend to be a bit more susceptible to RF interference than a dedicated amp tucked away in a rack feeding passive speakers.

I'd keep several three prong to two prong adapters in my gig bag to use as a 'ground lift' if you get noise, unplug it, turn it around, and plug it back in upside down.

Bad practice and bad advice!

Forget about calling those 'adaptors' a 'ground llift'. They are nothing more than a ground eliminator. Electrical equipment is designed to be grounded for a reason... SAFETY!

Eliminating the grounding of equipment that is designed for it is dangerous and unprofessional. A true professional would invest in proper ground-lift equipment for noise reduction. To do otherwise is inviting an expensive lawsuit in the case of an equipment fault.

By that rationale, a 'true professional' would refuse to play a gig because the electrical system in that 40 year old club was goofy, or carry an isolation transformer or two in their trunk just in case.

I've been playing bar gigs in bands and karaoke for 22 years. I haven't juiced anybody yet.. but using those adapters and flipping them around has kept me from getting shocked on mics in clubs where some of the outlets were wired backwards.

One other person mentioned the answer here and it is inductance. Your speaker cables or another signal carrying cable are probably running along near where the speaker cables for the jukebox are run. The result is an inducted signal in your system feeding the speakers.

One question, why in the world did you turn on your speakers without having your mixer turned on? The speakers (or more specifically the power amps) should be the last thing turned on and the first to be turned off.

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DJ Tony
Let It Rip Karaoke

Letitrip, I had detected a hum earlier in the day, so when I came back I wanted to check (just the speakers) to see if the hum was just a hum coming from the built in amp, or if it was a ground hum. So I turned them on with the intent of putting 3 prong to 2 prong adapters if needed. This is NOT my normal practice. Usually the speakers go on LAST, and are shut down FIRST.

Rosario

I use windscreens or signal ground lifts for this.

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Jeff Wheeler, moonlight DJ/KJ

Like I said before, are you using any TVs or monitors from the bar......if that tv is sending or receiving a signal to or from another device(cable, other....) it will flow into your system. Usually video manifests itself as a hum, but audio can come out pretty clear sometimes.....the signal will find a path in multiple directions...ps, I've been using 3/2 adapters without hooking up the ground for 40 years.....never had a single problem, never heard of anybody having a problem.... but even the amps from a usb port is enough to kill you.....

Hmmm.
Mutual inductance. Not sure how that is possible without transmission.