So with that done, let's look at the main problem that everybody hates, and you're soon become a master of eliminating. And that's feedback. So here it is, in a nutshell, we're back to our little mini pa here with a microphone and a speaker. If we place these guys close to ensure that you'll, you'll get that unpleasant sound. Now, there are two ways to fix this problem. either physically changing the relationship between the source and the speaker and or you can control their levels.

Let's look at the physical side. First. This is a cardioid mic, as we've learned before it, meaning it's most sensitive around here and least sensitive on the backside here. So if we place this mic and the speaker like this, and they'll, they'll take off right, it's much better if it plays this way. That's why you always want to have your monitors down by your feet as because they are facing the least sensitive power microphones. Fine, so that you can hear the monitors.

Hey, hey, I can hear it fine, but it doesn't take off. By the way, don't make the rookie mistake of copying your hand over the mic when it squeals check it out. Because, in fact, let me just turn this off. Your hand ends up being a perfect parabolic shape that focuses the sound of the feedback rather than the most sensitive part of the mic. It ends up just being like one of those parabolic field mics you see on TV and all the pro football games ends up being a perfect way to do that. So keep the line of sight of the speaker's kind of aimed away from the from the most sensitive parts of the Mac surface is the Front of House Speaker out there to the audience, then that's a good way to go.

If it's gonna be a massive in this should be placed down at your feet. Also train your vocalist to put them mics behind their backs, when resume has not dropped down, aiming squarely at the monitors. So the two main culprits for feedback Be the main speakers and monitors. In terms of main speakers, you'll want to line your vocalist or you know any open mic for that matter up behind those main speakers. If you're a vocalist or pastor likes to walk out in front of the main speakers, then you're going to start having no concern. This is the feedback zone.

I wouldn't recommend being out there but if your vocalist really wants to be out there in front of the main speakers, then the best first line of defense is having a microphone with a very tight pickup pattern and getting that mic as close to the sound source being his or her mouth as possible. You see your worst nightmare is someone who likes to wander out in front of the speakers and who likes to kind of place the mic down here like an accessory. If you can't hear the person, then you're going to have to crank this up. You're more and more and then check it out. The mic is both vocalist and the front of house speakers and you start to get really, you want to maximize the good signal from the bad signal and also the older flexes on here. So train your vocals to really get up on that mic.

So the ratio of good vocals overpowers all the other reflections. You know, let me just turn that down. This is true if your vocal stands anywhere but crucial if I like to walk out in the audience. I'm not against people walking out in the audience, but inform your vocalist that they will have to use a microphone that has a lot of rejection that is going to be a cardioid mic and don't need to really get up on that mic. If you're a church sound person and your pastor likes to walk out around the sanctuary, try to encourage him or her to use a head one mic they work really great in this scenario. As I said the other Danger Zone is a is on the stage in the form of on stage monitors.

That is why it makes sure They are down at the speed of your performance. So they're naturally in the rejection zone of your handheld microphones, as some people like to hang monitors up above to get to kind of a clean stage look. But remember, they are now in a more sensitive angle, in regards to microphones and feedback might be more of a risk. It actually happens around a drum kit. So you might have six or eight open mics around a drum kit, that no sound coming out of a drum is massive, just angle those mics away from the monitor to cut down on that feedback. By the way, feedback can happen on things other than microphones.

If you leave a guitar sitting right next to an amp. With that volume up, the strings on the guitar can start to vibrate. And then you can get feedback in that same way. I actually remember one time is a long time ago. It was a really low rumble on stage when I used to sound a megachurch, all that musician had left the stage and I had everything muted except the pastor's level ear mic. Those this rumble around hundred hertz.

That was just billing and coding and billing. I couldn't get it out of his mic. I suddenly realized that the bass player on stage had not turned down his bass and left the bass on a stand like right next, the app and a string was done the feedback on its own. Yeah, I had the base that Muse on the main speakers, but it was just reading on stage to his base apps are telling musicians to kill their instruments when they move up the stage because guitars can do that. Okay, so I think we have all the general rules of reducing feedback on a physical level. Basically, keep the mic and speakers and away from each other.

And try not to have your mics most sensitive access in your feedback zone. Now, the other way to reduce feedback is to just lower the overall level or in particular frequencies that are feedback. You might just want to just pull down the overall level of all the vertical monitors. If you're getting too much ringing, sometimes band members can get involved in loudness wars. And you may kind of need to play bad cop and just say, hey, the stage volume is just too loud. And we just have to tame everything down.

In some situations, you can slice out problem frequencies, not at the source. But in the monitors. You can place a graphic equalizer or a third band equalizer to notch out particular frequencies that are feeding back. You can try to do that at the source microphones channel but that will fix everything you know, it'll affect everywhere, including the main mix. If you notch out a little of your problem frequencies at the monitor, then that will be cut but anything going through that monitor, it's just very handy for giving you a much louder signal before feedback. So I mean, how do you find those frequencies, simply just push Go through the various things isn't so you hear one take off.

Then watch out a few DVDs at that particular frequency and you'll be good to go. One last great way to kill feedback, particularly in a spoken word situation like say a pastor's head one mic is to use a noise gate. And we'll look at noise gates in detail in the next section. But they're basically like an automated way to pull down the level when you don't have any signal above a certain threshold and open up. So take my exam, my broker, for example, if I set the threshold totally open, then the signal won't get get it at all. If I pull it down a little bit too much, then my soft words will get kind of cut out, check it out.

Right now everything's getting through, but if I speak softly, yeah, it starts to cut out. Now if you said it just right, then the gate will be open when I speak and then kill a signal when I don't properly set Noise gets a wonderful for the spoken word as it cuts out or you can even start just to lower the volume slightly when when a signal is below a threshold so it never really gets a chance to take off and feedback lamp. So to review the sources of feedback first identify where the loop is taking off and then see if you can position the two elements, the microphone and the speaker so that they won't be as sensitive to each other and try to use a microphone with a very tight pickup pattern like you know a caddy or even a hyper cardioid and position the mic as close to the source as possible.

So the ratio of direct sound and you know possible feedback you know is maximized. You can also notch out certain problem frequencies on the speaker on the monitor and but I would restrict this only to really onstage monitors I will never start messing with a front of house. Mix and funny and noise gate can be particularly helpful, certainly in the spoken word where the gate clamps down and reduces or even cuts off the stage. Go between words that were the signal doesn't get a chance to start taking off marine. Okay, so moving down our Gremlin list, we have distortion and noise. They're big.

They're kind of related here. These are big ones, I hear a lot of systems that are incorrectly set up and produce lots of distortion and also noise. And all of these problems really stem from incorrect level settings, somewhere down the signal chain. And as we've seen earlier on, there are under a lot of levels. From sound source to speakers, we take this example, we have a wireless microphone transmitting into a receiver, which goes into an input channel gain, which goes into the input data through a main fader. through some apps, main to West speakers, I see about six points in which we can set levels.

Now each of these points within the signal chain have a sweet spot in which they should be set. And that's sweet. But it's probably about 80% of the maximum signal that a particular element within this chain can handle before distorting. In every part of the signal chain, we have a dynamic range, like this diagram. At the top, we have distortion. We don't want that right.

But some might think, okay, I want to start you know, right away from that and, and I'll set my levels you know, right down here. Well guess what, all the noise lies down here. You don't want to set your levels to be sit down here because you'll probably need to add that signal up. In the next button. The signal chain amping up both the original good signal and that noise set at too high and you'll get distortion too low and you'll have a bad signal to noise ratio that will haunt you as you get further down that signal check. So go ahead and set your levels the max that you can do without distortion in some parts of the signal check.

That might be a meter like this that you'll want to set. You know it So it goes occasionally in the read on some part of the signal chain, it might just be an overload LED, but you need to adjust until only the loudest parts clip momentarily. The truth is some parts of your signal chain overdrive gracefully, some just run out of headroom and just just crunch. You'll get to know how each particular piece of equipment, overdrive, but I just wanted to kind of get this idea rock solid in your head. Each part of your signal chain should be operating at this sweet spot far out of the noise floor but not too high to overdrive it. So in our system here, here's how we could set it up.

You could have an overdriven wireless mic, which is distorted and then it doesn't matter what you do further down that chain because once you're distorted back here, then there's really no way to fix that downstream. So then you get all paranoid and back off again of your mic and also the transmitted output, and then you'll need to crank up the gain of your input channel so the mic can be heard. And guess what, you'll bring up all the noise of the mic and a transmitter for a horribly noisy signal. So the best way to have all your signals set is to have every part of your signal chain couldn't be in their own sweet spot. Let's go back to our little tiny pa here. Here's a real world example.

Okay, I could back down the level of the very first channel here and crank this all the way up. And you could hear me fine, okay, but listen to all that noise. Compare that if I was to back this back and bring out this guy hit now I have a much cleaner signal and much less noise than we had before. That's the idea behind all the gains that are the signal time we call this gain structure actually, you might just want to, you might want to call it leveling out your signal chain. And here's another analogy that might kind of help you understand Imagine that each part of the signal chain was a photocopier that could enlarge or reduce an image. And maybe I took an image and blow it up 200% on the first one and then back down to half on the on the second one, and then I blew it up 400% and then reduce that to 25%.

You get the idea, right, you could end up with the same size document at the end of this photocopied chain. But man, it would be mangled from all the blowing up and the reduction the same way the signal level down your chain can really get mangled by incorrect level settings. So how would you set up a signal chain? First of all, I set up the main base of the zero DB mark or sometimes it's labeled unity, that the point where the fader is passing through signal without any amplification or reduction. I then place a CD player into a line input and play it through the main speakers that are just the main apps until you get the system loud as you typically want it, it may be a little more. That way you know that the amps are not pushing out any more power than they need to be.

This probably won't be as big deals for you guys who are in a loud club, you might just want to max out the output of your ads, because you want all the power you want. And the truth is the club is never quiet enough to hear that amp noise. But do you guys mixing in churches where you have kind of a semi loud band and then the remainder of the service is just a preacher with a you know, a quiet microphone, just one input and why would you have the whole system cranked up like this when it could be back back and you know, that will give you a much more quiet. That's why I recommend playing a CD to bring up you know consistent levels and then crank up the amps to only what you need plus a little bit more. Then you go back and adjust all of your levels back from that So that makes sense.

I've actually gone to church as an audit auditoriums where the base level of the system is just as noisy as all get out. And then you know, all the amps are cranking out this noise. And everything's kind of turned back. And you end up with a really, really noisy system that you don't notice when the whole band is playing, but just sounds like sizzling, when you have a quiet spoken word, run through it. So that kind of takes care of the back end of the system, you then need to work forward from the input. And really all the decisions as to how loud something is will take place at the gain or the trim knob.

Just set the amps like I showed you there. All the faders can be at the zero DB mark or about 80% of their throat. And then all really all the major adjustments really come down to the gain or the trim knobs right up here. If we look at the wireless mics expression, you'll quite often have a gain control on the actual microphones now it won't look like a normal trim pot or or a gain control etc on a mixer but quite often, it'll be like a little micro switch from a micro dial I actually took this off the out of a shore owner's manual, one of their wireless mics you can see on the bottom of the microphone, there's a little slider there, that will adjust the gain of that mic in whatever way you do it. Here's what you do, you have your vocalist sing as loud, I mean, not as loud as they can, but as loud as they will normally sing into that microphone and then you adjust that wireless mic gain looking at the signal on your receiver.

In this case, we've hit too hard so I'll back up that wireless gain until you get a good signal to noise ratio and that'll be nice and clean. By the way, a lot of receivers will have actually a headphone jack. If you can plug in a headphone, it's a great way to kind of additional audition, how clean that vocal is and whether you're getting clips right there at the beginning of the chain. If you've set up you know everything correctly then your signal will be strong enough but no distortion and with all the data sets about the zero DB mark, then you all need to do is adjust your input trim or gain knobs. Keep in mind, if you ever see that your wants to see it probably has a volume knob set that to zero DB or about 80% of its max. So do you understand how we attack a signal levels from two ends first from the AMP side then from the input side, like I said, bar up a CD player into a line input or a stereo turn will all the settings down here at zero dB, set up the main amps to a cup a comfortable listening level, like in which you'd normally run the system plus a little bit more.

Then adjust any wild systems so they're at their sweet spot setting, you know, sweet spot setting wise and make your adjustments or up here at your gain or trim knobs with your system set up this Wait, it'll be way quieter, you'll have noticed or some and you'll have just a really great sound of what's ahead. The rule of thumb is, if you have distortion, you're you've over driven some part of your signal chain. And I would always start at the input first. If you have too much noise, then some part of your chain is set down to low, and you've cranked it up, bring up the noise, that it check these out, go through each part of the system, one stage by one stage through your chain. If you're getting distortion on a mic and start off with a mic, maybe your sound source is just physically too loud for that particular mic.

You can't put a delicate condenser mic in front of 130 Db snare drum. Use the mics I recommended a while ago and you know all should be good to go. If you're using wireless mics than the technique I said a moment ago with adjusting levels on the actual mic and monitoring if possible from the receiver works really really well. Basically the main Place in which distortion will occur is that you know, at overbought the gain or trim knob. So take out your troubleshooting hat and swap out mics adjust wireless levels and so on. Humans can be quite a problem in audio and can originate from external interference, which can be greatly reduced by using balanced lines that cannot be XLR lines like these, or tip ring sleeve quarter inch cables like this, that what both these cables have in common is that they have two signal paths and a ground rather than just a signal, you know, one signal and a ground.

And those two signal paths are actually what 188 sorry, 188 how to get that 180 degrees out of phase so that you can reject a lot of that interference that's coming externally. Now if you have a number of audio sources that have multiple paths to ground, you can get a ground loop that can be reduced by pairing your devices like say guitar amps and since from a coma AC source, like, say a common power strip. Now if you're still having troubles, you can break the loop quite often with a DI box. Most of them have a little ground lift button on them and when you select that, then that can lift the ground and get rid of a lot of ground loops. Now keep in mind that a lot of other Gremlins can cause hums. Like power supplies quite often if you have a pacifier sitting on top of you.

And you move that around you can kind of hear that hum gone around, keep them a safe distance away from your your amps and other sound sources so you can get rid of that. So clearly, these are all things that you don't want to be doing all of these in the middle of a performance right? You want to tackle and deal with all of these problems before you ever seen audience that is why you really need to have soundcheck and a soundcheck is just basically, you know a rehearsal With a band so that you can go through, you know, all of these checklists and making sure that you can hear the vocal Well, you know, the effects of this right the Mars has are working well, and the performers can hear themselves as well, all at the same time that the performers are working kind of on their stuff.

So a line check should be done before the performers get on stage. And, you know, all you're checking is that all the lines are up on your board and you hear the inputs, you know, distortion and hum pre check all the mics, input jacks, wireless frequencies, and all that kind of stuff before the band turns up, then you can just concentrate on helping them with their monitors, and also bring up your main mix. So we put all the main Gremlins to bed. We know what a signal chain is and how to get a gut level of ideas. Kind of how you know where the problem might lie ahead of time feedback, distortion, noise and hum. Let's get to the fun part of being a sound person and that's mixing