Home

EQ & FBQ and the Shark

(Video transcript) Hi. Paul Donovan here from AVTechnician.ca Thanks for watching my channel. This is the channel where we're giving tips and tricks to AV technicians and those who would like to be an AV Technician.

Today I want to talk about equalizers in the sound systems. But also I want to talk about special unique item called FBQ which is a product that helps you use an equalizer. First off, EQ means equalizer. Many of you may not have realized that but that's what it is. What you'll often see, you'll see in your mixer board will a few little slide bars that are mini-EQ for your system. You also have in each channel, quite often, a low, mids and highs. Lows, mids and highs. dials, that is also considered EQ. Then you can get an EQ that is a separate box. Quite often stereo, sometimes stereo side-by-side or top and bottom. These are are EQ's with a bunch of slider often 20, 30, 40 sliders. Each one allocated to a certain frequency of sound.

A lot of people use the EQ buttons sometimes for the wrong reasons. Unfortunately it's the only reason that really is done a lot in the AV world. When we are often having speakers speaking and they're wandering around with microphones towards speakers, a little to close. We have to watch for feedback. When we do this we want to try to find a certain frequencies of a room that can cause trouble. Good technicians will use just their ears and slide up and down or dial up the lows, mids and highs to try to tune out some of the things. A lot of times it'll be the mids you'll be turning down. To eliminate feedback to give you enough volume.

The average user expects that if you have a microphone you just turn up the volume and it will just work. They don't realize that when you turn it up too much you get a lot of squeal and feedback. So our job with EQ'ing is to try to reduce that. What a lot of time we do, I see a lot of techs especially the setup crew, who will just bump down the mids, anywhere from 20 to 30% down, that way they can get enough volume and eliminate a lot of feedback issues. If you've got a full track, 10-channel or 30-channel EQ you have a lot more control.

There's a company named Behringer, and I know there are other companies that do it, but Behringer has a product in their mixers and so-on, called FBQ. Feed Back Q. This is a button that you turn on and what you do then, and I tell, if I've got a room full of visitors, delegates, or this early stages a few people inside, "Everybody watch out, I'm going to make some noise" That's what I'll tell them. What I do then is will get all the microphones turned on all my EQ's levels are straight across, all my channels dials are all straight up and down, 12 o'clock. Then what I do is I turn up the volumes of some of the microphones until I start to hear some squealing. You can use your ear and sort-of guess where those ranges are. But Behringer boards have this FBQ button. If you press the FBQ button the little red lights on each of the sliders will go off. Oh, you think to yourself, Oh, that turned off my EQ. No, what it did is that the FBQ on the board is actually now listening to the sound.

Now you slide up the volumes a little bit until you start to hear some squealing. What you will notice in the bars is the little lights will light up as you reach that frequency. It helps to determine it's the 100k frequency or this is a 50k frenquency You can crank that one channel (slider) and it helps clear off the squeal and it happens across the board. You want to have your lapel mics or your headset mics or your handheld mics or the wired mics all turned on. All these microphones are picking up the sound of the room. Then you can find what frequencies are cause the most difficulties.

The best thing for you to do, in my case I like it, cuz a lot of the boards I work with are Behringer boards I turn on the FBQ, and a lot of my co-workers don't know what it does, and it's often turned off. I turn it on then I turn up the microphone volumes and I notice a channel squealing I'll just bring it down, bring up a little more volume as it's starting to squeal. I'll bring down the ones that the lights are on. When this is happening is that I pull off the frequencies. I push in more volume than I'm actually ever going to need for the room. But what the advantage is that during the event if I have all the microphones turned on, I'm hoping not going to have any squealing or feedback happening. So FBQ really helps me to be able to determine it.

I have seen people use apps on their smartphones or tablets that will also do the bouncing and tell you which frequencies are causing the trouble. But it is actually monitoring the sound from the actual room. Whereas the FBQ thing on the Behringer board is monitoring the signal itself and hearing feedback within the signal and catching it.

In fact Behringer makes a device called the Shark. I've only ever seen one of these devices, and I've seen it used by a guy who actually knew how it works. A Shark is like FBQ on steroids. It will handle frequencies, it'll handle automatically. It finds all the frequencies that are giving issues and automatically brings them down. It has a little bit of compression and limiter built into it as well. The only thing I don't like about the Shark is that it only attaches to the single output of the board, which means it doesn't do it's work on individual channels. I did see one time in photograph where somebody had a bunch of Sharks lined up together for each channel. The Shark was lined in the insert stream. So that there was a Shark for each of the microphones. That was very smart, but those Sharks are not cheap. I've seen a guy who really knew how to make it work and it was amazing. He basically gradually turned up the volumes across the board, on the whole thing and as the Shark was learning, pushed the buttton and said learn. As it was learning it learnied what frequencies were causing troubles and was adjusting the EQ levels for those frequencies and it was also taking the compressor and limiter activity on the channel as well. It was only working on the single output feed. Taking a cross-section of the board of all the microphones. Remarkable device If I can remember I'm going to put a link in the description that will point to it.

There's a brief tip on use EQ and the FBQ feature that is available in a lot of Behringer mixer products. This is Paul Donovan from avtechnician.ca Please check out our website at www.avtechnician.ca. Subscribe to this channel to keep up with what's happening in the world of AV technicians. Thank you for watching.