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Feedback Issues
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Author:  FlyGirlKaraoke [ Sat May 23, 2009 9:32 am ]
Post subject:  Feedback Issues
Help!

I just landed a new gig and for some reason, I'm getting feedback from not only my music, but my mics as well. It's the strangest thing I've ever experienced. This is not a problem I'm used to having. I've always balanced my volumes. Yet, this location has been a challenge with feedback.

My speakers are at least 20 feet from each other yet I believe it has something to do with the shape of the place. I've even had a more experienced KJ come by and for some reason, we still can't figure it out.

*Note: The place has a dance area (where my system is) that is somewhat enclosed but I've taken my speakers and placed them closer to the audience outside of the U shaped area. I've heard other KJs have have the same feedback problem at this location. Any suggestions? :oops:
Author:  karyoker [ Sat May 23, 2009 9:47 am ]
Post subject:  Re: Feedback Issues
Are the walls hard like cement blocks? Are the mics close to and pointed back at a wall? Try to show a diagram of the room.
Author:  LondonLive [ Sat May 23, 2009 9:56 am ]
Post subject:  Re: Feedback Issues
It would help to know what you have for a PA and how it is configured, but with the limited information I could speculate a little.
The fact that you said your music itself is feeding back also would tell me you might have an auxiliary send open on a channel that it probably shouldn't be, quite possibly an FX send. Remember feedback is what occurs when a signal is returned to itself. Feedback is usually associated with a mic picking up a signal from the speaker and reintroducing it into the mix. Basically an open AUX in the wrong place can do the same thing with a line signal. Does it occur on your music even with no mics on for example? This information would help determine the cause. With a little more information we could probably come up with a little more specific answer.
Author:  karaoke koyote [ Sat May 23, 2009 10:38 am ]
Post subject:  Re: Feedback Issues
I doubt very seriously you are getting "feedback" from your music. Sounds more like you are getting a line hum... but it hard to say with the little bit of information you've given.

What mixer do you use? Amp? Mic effects???

if you're getting a hum with mics closed that's a sure indication that a line wire is crossed somewhere. If you're playing in a larger venue this will become more apparent as you increase your power usage to compensate for the larger room, which explains why you haven't heard it before now.
Author:  FlyGirlKaraoke [ Sat May 23, 2009 1:28 pm ]
Post subject:  Re: Feedback Issues
Ok,

Let me address some of things things asked.

1. I didn't think about it but the walls could be concrete! I've never played in a place like that before.
2. My amp is Idol Pro 999, Idol Pro Wireless VHF mics
3. Now that you mention it, it's a hum...more like a hum than feedback..thanks for mentioning the hum
4. I don't believe size is the issue. I've played at a much larger place but the other location's layout was very open spaced.
5. I do believe the mics are picking up the sounds from the speakers. I've tried to compensate by moving my speakers in front of the singers. That's why I need a Floor Monitor now.
6. The mics aren't close to a back wall.
7. The only time I hear feedback/hum is when the mics are on and I'm trying to turn the music or mics louder. (This may be important)
8. I've checked all wire connections. The KJ before me had the humming problem as well. This is something that has happened to more than one of us.

I can pull up the Photo Shop and try to draw a diagram. This is how the place is set up:

With my face toward the singer:

Singer is in center. A speaker is on each side of the singer and the speakers are at least 20 feet apart.

The singer is actually about 3 to 4 feet behind the line of the speakers

The area where the singer and KJ is, is a U shaped area. The speakers are at the both ends of the U. The KJ station is along the wall at the top of the U near the speaker. It's basically an enclosed stage/dance floor area. When I use the term U shaped, it's half a rectangle. Just using the U to show there is an opening.

Hope this helps. Yet I do have to point out, it's more of a hum than feedback now that that has been brought to my attention. I sincerely appreciate everyone's comments.

**Note: If I move the speakers back towards the back of the stage area, behind the singer, the hum gets worse.
Author:  karyoker [ Sat May 23, 2009 2:43 pm ]
Post subject:  Re: Feedback Issues
Ok some things to do. Get one of these tester (in fact all ought to have one) and check the outlets. Im assumimg it isnt a ground loop issue in your gear and common to this venue. Next turn off all channels except one mic channel. Turn the gains up and when you hear it cover the mic grill with your palm and see if it is the mic picking it up. You are using TRS mic cables or balanced mics? Does speaker placement or direction affect it?

If not it could be RF interference coming in on the pre input (does the mic fader affect the hum?) One old trick is getting a cheapy transistor radio on AM turn the gain up off station and see if you get hum or interference. You can actually locate the source this way.
Author:  RLC [ Sat May 23, 2009 3:39 pm ]
Post subject:  Re: Feedback Issues
FlyGirlKaraoke @ Sat May 23, 2009 3:28 pm wrote:
The KJ before me had the humming problem as well. This is something that has happened to more than one of us.


The above statement stands out and would point me first in the direction of the venue it's self. As karyoker suggested, check outlets. Also look for other sources of interference-bar lights, game machines etc.
Author:  ripman8 [ Sun May 24, 2009 6:51 am ]
Post subject:  Re: Feedback Issues
karyoker @ Sat May 23, 2009 4:43 pm wrote:
Ok some things to do. Get one of these tester (in fact all ought to have one) and check the outlets. Im assumimg it isnt a ground loop issue in your gear and common to this venue. Next turn off all channels except one mic channel. Turn the gains up and when you hear it cover the mic grill with your palm and see if it is the mic picking it up. You are using TRS mic cables or balanced mics? Does speaker placement or direction affect it?

If not it could be RF interference coming in on the pre input (does the mic fader affect the hum?) One old trick is getting a cheapy transistor radio on AM turn the gain up off station and see if you get hum or interference. You can actually locate the source this way.


Currently unavailable at amazon.
Author:  jeffsw6 [ Sun May 24, 2009 10:13 am ]
Post subject:  Re: Feedback Issues
You can buy an electrical outlet tester at most hardware stores with an electrical section. It will have lights that indicate bad ground, reversed wires, etc. I agree this is a good place to start looking for the source of the "whatever."

I would like to better define what the "whatever" is, since it might be AC hum, noise from lighting or motors, or maybe it really is feedback. Is it a steady tone, or does it sound more like pink noise? Does it happen with wired mics? Anytime you have an issue with inexpensive wireless mics, the first thing to try is swapping them for wired mics. Can you change mic radio frequencies?

Is your stage wedge/monitor gain up pretty high, or are you testing without it? Has your friend (the more experienced KJ) tried to attenuate or eliminate the sound with an equalizer?

Finally, where are you located? If you are near a big city, I bet you could find someone on the ProSoundWeb forum who would drop by and help you troubleshoot for a case of beer. There are a lot of posters on there but it's not really for karaoke.
Author:  karaoke koyote [ Sun May 24, 2009 11:48 am ]
Post subject:  Re: Feedback Issues
Here's a really good question. Are you using a Furman power conditioner????

I can tell you, this solves a lot of issues with dirty AC from clubs and bars, and can save your system in the event of a surge.

Another issue you might have is your amp itself lacks certain professional features that supress feedback. I used a similar amp myself in the past and ditched it in favor of a more professional mixing board with digital compression and feedback suppression. I am now 99% feedback free... even when the singers walk close to a speaker (my mics also have feedback circut also).
Author:  mckyj57 [ Sun May 24, 2009 3:30 pm ]
Post subject:  Re: Feedback Issues
karaoke koyote @ Sun May 24, 2009 2:48 pm wrote:
Here's a really good question. Are you using a Furman power conditioner????

I can tell you, this solves a lot of issues with dirty AC from clubs and bars, and can save your system in the event of a surge.

I thought we disposed of this in the last thread. The "power conditioner" doesn't. It is a good power strip with halfway decent surge protection, but no more.
Author:  jeffsw6 [ Mon May 25, 2009 4:57 pm ]
Post subject:  Re: Feedback Issues
Yeah, I think the only thing a "power conditioner" might do here is identify bad building wiring. You can find that out with an inexpensive tool from a hardware store. The cheap Furman units are snake oil as far as "conditioning" is concerned. They are convenient with the front & rear outlets and lights, though!

I sorta thought about suggesting a "feedback destroyer" to the OP (karaoke koyote mentioned liking his) but I am not so sure that her trouble really is "feedback" and not something else, like maybe poor reception on her wireless mics, or the Dalek headquarters hiding underneath the stage.

If she can borrow one for a night, a feedback destroyer would probably be worth trying out; but I think most people here agree that it's better to avoid using those things if you can. Check out the picture I posted of mine after a few hours of music playing through it, with no mics or speakers (so no feedback at all.) It created like 10 notch filters that were unnecessary.
Author:  Bazza [ Tue May 26, 2009 3:32 pm ]
Post subject:  Re: Feedback Issues
jeffsw6 @ Mon May 25, 2009 7:57 pm wrote:
They are convenient with the front & rear outlets and lights, though!


You got that right! ;-) Love mine!

Another easy test would be to run a long cord to an outlet on a different circuit and see if the noise goes away.

Unless the whole building is wired incorrectly of course...
Author:  JD [ Tue May 26, 2009 5:54 pm ]
Post subject:  Re: Feedback Issues
Whenever you play wherever you play you can run some pink or white noise through your system. the use a RTA (real time analyzer) or an FFT (fast fourier transform) program to catch any resonant frequencies in thet venue. These programs are available all over the web including some in share or freeware forms. The resonant frequencies will stick out like a sore thumb. Adjust your eq'ing and speaker positioning accordingly and lastly do a sound check with program material.
Author:  Lonman [ Wed May 27, 2009 2:03 am ]
Post subject:  Re: Feedback Issues
FlyGirlKaraoke @ Sat May 23, 2009 2:28 pm wrote:
Ok,

Let me address some of things things asked.

1. I didn't think about it but the walls could be concrete! I've never played in a place like that before.
2. My amp is Idol Pro 999, Idol Pro Wireless VHF mics
3. Now that you mention it, it's a hum...more like a hum than feedback..thanks for mentioning the hum
4. I don't believe size is the issue. I've played at a much larger place but the other location's layout was very open spaced.
5. I do believe the mics are picking up the sounds from the speakers. I've tried to compensate by moving my speakers in front of the singers. That's why I need a Floor Monitor now.
6. The mics aren't close to a back wall.
7. The only time I hear feedback/hum is when the mics are on and I'm trying to turn the music or mics louder. (This may be important)
8. I've checked all wire connections. The KJ before me had the humming problem as well. This is something that has happened to more than one of us.

For a quick & simple test - get a cheap 3 prong adapter for the system.
http://www.radioshack.com/product/index ... Id=2104010
Plug the system in to that, if you don't have anymore hum, it's a ground loop issue in the building itself. That was only a TEST! If there is no more hum, you want to 'properly' remove the ground loop with something like the E-Btech hum elimintor
http://guitars.musiciansfriend.com/prod ... sku=150452
The first is a solution is good for diagnostincs, but not safe for regular use, especially if people are touching metal - ie mics.

As far as feedback, it's all a matter of mic & speaker placement!
Author:  jr2423 [ Wed May 27, 2009 2:46 pm ]
Post subject:  Re: Feedback Issues
I experienced a hum at a venue I have played for a few years without incident until one night. I used the venues big screen TVs. And this one night I was not aware that the venue had just connected to an outside antenna and installed an RF amplifier. As soon as I set up and turned things on for a sound check, there it was. I played all that evening EQing the hum out as best I could (boy was my mixer screwed up as a result). Then towards the end of the evening the guy who did another night at this same venue advised me of the new antenna connection and that I had to disconnect the antenna to clear the hum. What a relief. Of course I still had to readjust my mixer yet one more time.

Another time I was playing a small private party and I had my Kustum PA plugged into the same socket as my Furman power conditioner; into which all other components were plugged. I experienced what I thought to be a ground loop. Strictly as a shot-in-the-dark move, I shut it all down and plugged the PA into the Furman. When I powered back up, the hum was gone.

Just thought I add a couple of more possibilities causing the hum.

As for the feedback, I'm always leery of halls with multiple hard/shiny surfaces. When I started out a few years ago, I played a place in Vermont where the singer's back was to a large mirrored wall and the house provided audio monitors mounted on a low ceiling. So there I was with a mic sandwiched between monitors and a mirror with an owner who needed extra monitor because he was hard of hearing. Yeah! If he didn’t keep that mic directly in front of his body…, well you get the picture; good thing you didn’t have to hear it.
Author:  fsapienjr [ Wed May 27, 2009 3:33 pm ]
Post subject:  Re: Feedback Issues
In my experience, the hum has been on of two things.
1. A ground loop. Is all of your equipment on the same circuit?
2. Something else on the same circuit. I have got this when plugged into the same ciruit as, Neon Lights, they use a ballast to boost the electicity to a high enough voltage, this causes a hum. Same circuit as a refrigerator or fishtank, these also cause a humm.

Have you tried using a different power outlet on a different circuit. At my venue I just had to move off of the circuit that the Neon lights are one. New plug and circuit, problem gone.

Felix the KJ
8)
Author:  FlyGirlKaraoke [ Fri Jul 24, 2009 9:09 am ]
Post subject:  Re: Feedback Issues
I want to thank everyone. I bought new speakers, played around with the height of the speakers, the angle of the speakers, and resolved the problem. For some reason, I don't have feedback or hum anymore. Once again, thanks so very much for providing feedback (no pun intended). :D
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