Need some tips on using Behringer Shark to fight feedback
We have a portable PA system that goes out to events all over the place, a different venue or location every time. A large number of the locations are not great acoustically, they are reverberant, and it is hard to crank in enough gain on the speakers to be heard, even with proper mic papcement, yet avoid getting ringing feedback sneaking in.
We are looking at a purchase of a Behringer Shark 1100 0r 1124 to try and kill all the feedback, and currently have aquired their model DSP-110 to play around with the concept of active feedback canceling. However, our engineer is not expert in the field of acoustics and is kind of stumped by how to use it, and then how to train some cameraman or casual borrower of the PA to also use the unit properly. We have the instruction manual but results are so far not what we hoped for. Seems like its not doing anything at all.
So, before spending on the 1100 or 1124, any good tips or techniques to apply this DSP-110 unit to the PA efficiently? Or is there a better device for this out there that is affordable? The keys are economy and ease of use.
Thanks for any ideas or suggestions.
I'm not usually one to trash a product, and I haven't used any Behringer products in years. The reason I haven't used their products in years is that Behringer gear is garbage. Not one self-respecting professional would use a Behringer product, even if you put a gun to their head. They are poorly made and sound terrible. They are aimed at high school wannabees who forego their pot money for a week.
There are a few products that will "automatically" suppress feedback, but it still requires some set-up time and some audio knowledge. Shure and Sabine make products that do a decent job, but the run in the $300 to $600 range.
Thanks Bob for the quick "feedback" :-), got any model numbers you think we should look at?
Yah, here's one of those penniless high school dropout dope smoking wannabes. Note position of his right hand:
James Cameron on set of Avatar
Feedback Fighters are not the cure-all to feedback that they are popularly marketed to be. Any good ones will have different types of filters that can be set to certain frequencies that always feedback versus filters that adapt to the frequencies that pop up in different venues, temperatures, etc.
First and foremost: we need more information. What are you doing with your system - talking head gigs, bands...??? Next, give us a list of the gear that you are using. Make sure you tell us the exact order in which everything is hooked up, too, so we can analyze any problems there, as well.
Next, you need to identify the actual problem. You see, feedback is not the problem - it is a symptom of a problem. Often times, feedback cannot be corrected by EQ because it is not an amplitude issue, it is a phase/time-domain issue. By properly orienting the main speakers and microphones to each other, in BOTH space and time, you can achieve better Gain-Before-Feedback.
Without knowing any more information than you have given us, my first recommendation is to check your speaker placement. You've tried mic placement, but have you tried moving the main speakers?
More to come...
The system is very basic: a directional dynamic mic on a stand, generally no mixer, then 2 Peavy amplified speakers (basically portable guitar amps) in the 50-watt range, or a single powered speaker in the 100-watt range, placed so the mic is "behind" the speakers in the z-axis and the stage plane. We're hoping to replace these bits of kit with a Fender Passport of apropriate wattage some day, but for now, this is what we have on hand to make-do with.
The pair of speakers generally flank the podium set at 45 degree angles to "wash" the crowd, and can go up on stands or stay on the floor, depends on many variables as to which we choose at every occasion. Every time the system goes out on location, its a different venue; sometimes outdoor, sometimes indoor, small, hard-walled granite atriums, large warehosues or airplane hangars, and everything in-between... playing to a crowd of 25-50 people, sometimes seated, sometimes not.
It is just speaker support for press conferences, no music stuff. Very vanilla. A separate mic feeds a mult box for direct press access, with nointeractions with the PA.
The single cameraman we send out sets it all up after he's placed his camera and tripod and lights, so we want to keep things light, simple, and easy to handle. When we crank up speaker volume a little past one-third of capacity, feedback starts to creep in, first with just some ringing, then the full squeal if we don't cut back a little. This is where we would like to add an automated component just to cancel or suppress feedback, so we can open up the speakers to higher power level and not blow everyone's ears off with howling feedback. Our engineer found a deal on the Shark, so he's trying it for grins and giggles, but not getting dramatic improvement. So, what to do, and what to get? (under a grand).
Alright Mark, I think that at this point, a dedicated sound reinforcement forum would be the best place to go.
Check out ProSoundWeb's Sound Reinforcement forum, the "LAB Lounge". You have to log in to post, but I guarantee (1) you will NEVER receive spam from them and (2) it is the best place on the Internet to talk sound reinforcement. MAKE SURE YOU USE YOUR REAL NAME!!!
You'll get the answers you need to hear, though they may not be what you WANT to hear. Take it all in and think it over before responding.
Hello Mark and welcome to the Cow Audio Forum.
The solution to problems is not always more toys.
If the problem always happens, regardless of location, it's the tools or the operator.
Feedback happens when volume of the system increases enough to reenter the system.
It's that simple. Given your comments, questions that beg to be asked are:
1. Is the mic really a directional mic? What make and model?
2. How close is the mic worked when someone speaks into it?
3. Is only one mic used?
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
It's the directional version of the venerable Electro-Voice "hammer". I don't have one in front of me right now so can't give you a serial number.
The mic is worked at what I call "normal" distance, which I guage by spreading my fingers in the Hawaiian "hang loose" symbol, and using that distance from thump to pinkie to gauge mouth-to-mic distance.
Every time you half the distance between the sound source and the microphone, you gain a free 6dB of SPL. It's called the Inverse Square Law and it's a wonderful thing. All that to say: keep your sources as close to the mics as possible and correct with EQ when necessary for proximity effect (the increase in low frequencies as you get closer to the microphone diaphragm).
I still highly recommend posting on PSW. Hope to see you there.
Here's the thing: these are press events, not theatrical ones, so I have absolutely zero control over how each person steps up to the mic and uses it, and I don't have a black-clad stage hand standing by to adjust a boom or stand for each person that speaks. Coaching them does not help, and often is impossible to do. The mouth to mic distance I selected is, I feel, the best compromise between getting too close, and thus dealing with a lot of plosive b's and p's, and being too far off mic. This is live ENG news gathering; it's a totally different head from musical or theatrical work. You don't dictate terms to the users; you adapt to whatever they throw at you.
So, considering the relative simplicity of the setup, what if anything can I do using the Shark or other device to actively cancel feedback in these very fluid situations?
Mark, I understand completely what you're going through here. You will never get the various speakers to use the microphone properly. First, forget the Shark. Also, don't expect any great improvement from the Fender Passport. While it's a great little rig for performers in small venues, it won't get you anywhere with this problem. In the short term, move your mic. in line next to the speaker, neither in front nor behind, and as far from the speaker as possible. There's a bit of a dead zone there that should help delay feedback a bit. A better long term/cost-effective solution is to forget the self-powered speakers, as they lack any effective eq and look at some of the powered mixers from Peavey or Mackie, and one or two unpowered speakers. You'll probably need to up the budget, but setup will be very easy and you will gain a quantum leap in control over the audio. Placing this "pa head" next to your videographer will give him/her easy access to the eq and other controls to quickly and easily fix issues as they arise. Good luck.
RGB Media Services, LLC
I also understand where you are coming from. I was a broadcasting major in college and have done many shoots where you have to roll with the punches.
Until you get the feedback under control, don't use a compressor on the reinforcement mix. When the unit ceases to clamp down on the material, the feedback will come back with a vengeance from the newly-added gain.
Also, another potential solution might be to use a microphone with a Figure-8 pattern. Since there are deep, consistent nulls on the sides of the microphone, and very little bleed from surrounding sound sources, I think it may be worth a try. Just make sure that the other side of the pattern isn't catching reflections from the top of the lectern.
Actually, I've got a couple of Behringer Sharks that I use with a Fender Passport sound system for meetings in hotel rooms up to 150-200 people.
That said, the Behringer Sharks are more trouble than they are worth. First, they are multi-function devices with a lot of modes and settings. And they have to be tuned to the room. Maybe if somebody was doing this gig day in day out, they would eventually learn to work the things. I have not tossed them out of my gear bag, but they simply never get pulled out and installed at shows anymore. Maybe if I had an extra hour to screw around with them, but considering I've usually pulled an all-nighter anyway, the Behringer sharks just don't happen. They are marginal anyway. I'm more fascinated by their other features now; their feedback elimination is weak.
Back to basics:
Ty Ford and others here have given golden advice. The key is good mic technique.
My presenters use omni lavaliers. Once they amp up the volume in front of a live audience, it always works. Nobody I know believes in cardiod lavs, but it's your money.
About good mic technique. Executives exist in a reality distortion field. When you say you have no control, this implies the executive holds your function in contempt, somehow implying that if the exec had a real audio pro, nature's laws of physics would be suspended. Either get a new gig or go toe-to-toe and face to face with this arrogance. Sounds like you are dealing with a God complex, somebody who expects to roll forth heaven and earth with the sound of their voice.
Only their voice is not going to be heard without proper mic technique. If the President of the United States and Steve Jobs must both be wired or else speak directly into the mic, then your guys must do so also. You can look them in the eye and tell them this with absolute confidence.
After too many customer evaluation forms complaining about audio, I've had to get tough on our people. A major problem is non-professional talent who believe they don't really need a PA at all, and treat the microphone like some kind of Harry Potter magic wand, a "talking stick" they hold when it is their turn to speak, to be held somewhere down around their belt buckle, with a thumb hooked into their pocket. One of our guys is a repeat offender for putting the wireless mic into his back pocket. Don't know what they expect out of sound there, but it won't be good!
One tip, though, other than "telling them how the cow ate the cabbage."
There is no law written that says you must place the Fender Passport speakers to the left and right of the speaker's podium as if you were setting up a home TV set. In most of my presentations, a large rear projection screen has center stage, with the presenter's podium off to one side. I position the Passport speakers as close together as possible, cabinets side by side with front faces aligned in fact to reduce possibility of phase cancellation. But I setup the speakers on the side of the room opposite from the presenter. I also angle them away from the speaking position, to further reduce backwashing amplified sound back into the microphone.
There is no such thing as stereo audio in 99% of all sound reinforcement. If audio is right, nobody in the audience will notice there is audio.
The other thing to consider is positioning the Passport speakers forward of the presenter. Others here have said as much, but I tell people, "Feedback is due to the difference between the speed of light and the speed of sound." Essentially, the audio path from the speaker's mouth to the Passport loudspeaker occurs at the speed of light (electricity travels at roughly the same speed). The speed of sound, however, is vastly slower. So sound generated at the microphone comes out of the loudspeaker at essentially the same time. Once the loudspeaker converts the electrical signal into audible sound, however, the sound travels at a relatively leisurely rate through the meeting room. Feedback happens when the sound out of the loudspeaker reinters the microphone, then instantly comes out of the loudspeaker again. So you get an endless loop setup, first a little ringing, then an ear splitting howl.
That's why I don't think the Behringer Sharks are much good. They really don't have much effect on feedback, but they can, with great care, be tuned to stop a bit of the precursory ringing. The Sharks are multiband, multi-frequency, which amounts to addressing the specifics of tuning -- the exact frequency of feedback is affected by distance between mic and speakers, and standing reverberation waves in a specific room due to wall distances, etc.
So what if Behringer Sharks can notch these frequencies? This does not eliminate feedback, it only suppresses the early warnings of feedback. You can't make a pig fly. An SUV is not a Porsche, even though the SUV does have stiff handling. If you make the mistake of thinking the SUV will corner like a Porsche, the SUV will simply flip and roll with no warning. Consider the ringing sound that precedes full blown feedback to be "body roll" -- audible warning that things are about to go south. At that point, you are either going to be forced to gain down the volume, or else finesse mic placement.
The mixer is critical
When running multiple microphones, a simple mixer like my Mackie VLZ-1402 adds a critical additional safeguard against feedback. You cannot allow open mics. In our case, we have 3 people working the audience with wireless mics for Q&A, a wireless mic at the podium, plus lavalier body packs on one or two presenters.
Mixing can be a little hairy because I am usually the man behind the curtain. So I stick my head out during Q&A! I leave the VU channels gained up. Judicious use of the Mute and Solo buttons makes it easy to switch mics completely on or completely off as needed.
Updating this thread as I have used the DSP110, then the nearly identical FBQ100 for years. First as a very affordable noise gate & compressor for several different ham radio rigs. Then more recently we were setting up for a remote interview and found a set of squeals we couldn't remove easily. Rather than kill the audience participation mic, I had an FBQ100 with me and set this up:
We have had a great deal of success and carry either a DSP110 or FBQ100 with us for these remote interviews. We know FB suppression shouldn't be needed, but often it is just not possible to reposition speakers and mics enough, so hit the FB suppression button and the monitor output is clean. We also have used a 2nd DSP110/FBQ100 for noise suppression and elementary compression on the both input mics after having success suppressing FB on simple remote monitors. The compression settings minimize post-processing of the audio.
Another downside, though is that the JK Audio RemoteMix does exactly that and we have no track separation between telephone audio and local. For this application, that is acceptable as the RemoteMix is far superior in audio quality to the previously used custom boxes with audio transformers!
This setup works well. We could really use some advice on a battery powered equivalent to the DSP110/FBQ100 for better portability. Everything else is battery powered in the diagram above.