Correct Pro Sound Gain Structure

okay this is the first video I'm going to start doing with advanced videos on pro sound and this topic is on gain structure this is this is not a beginner video if you don't know how to use a mixer watch my mixer video if you're just buying the system I have a couple other beginner videos but this is an advanced video on gain structure and how to set it up so what gain structure is and a lot of people get this wrong this is the this and speaker placement are the two biggest mistakes people make even professionals make when running sound and setting up a system so I thought this was really important to cover and I wanted to explain it and the nice thing about these things you can try them if you don't believe me try them once and you'll see how well it works and you could always go back it's not a permanent change but this is a philosophy on how to set up gain structure and it's the best way to do it it saves you a lot of damage and a lot of wear and tear on your equipment and a lot of heat on your amplifiers because any time you overuse something you have a better chance of blowing a speaker you have a better chance your amp shutting off because it's too hot so this is a this is a correct way to set it up so the theory behind it and I'm going to show you how to do it the theory behind it is you got your input source in this case is going to be a mic but it could be a CD player could be in your computer it could be a guitar you got your input device you got your channel you got your output from here and then you got your input onto your amplifier and you could have more complex you get out you know you add crossovers you add eq's and stuff like that but just for simplistic and for theory this is this is basically you got your input device you got your channel you got your main out and you got your input on your amplifier so how game works is this is your input device for this and this could be any any device you want to get the most out of this you want to work your way down the game structure often the biggest mistake is people work their way up the game structure meaning they turn the sensitivity up on our amps the hallways they next they turn this up as little as possible and then they turn these up as little as possible what happens is when you do that reverse game structure like that your amps sensitivity is cranked okay first of all because your aunt sensitivity is cranked it's picking up everything that's why when you go in to see a band or go into here speaker it's like you get that hiss sound because the sensitivity is so far up on the amps it's picking up any noise in any of your equipment which all equipment gives off noise any of your cables and it picks up all that noise and it's unnecessary the other bad part about is that's where you get into blowing speakers because your sensitivity are in your amps or cranked the hallways up and I'll show you how to set those but yours are cranked so far up if something in a signal change say a pop say something would exit this mixer would shy off well just because you have the level down here that pop is going to throw a full force signal through your amplifier out to your speakers and chances are it's going to blow your horn same way with feedback if you have your since it's your gain structure in reverse order and it's maxed at the bottom of the chain everything is going to be amplified to its maximum output so that's why you always want to do a top-down gain structure so how you do it so first of all you want we are on channel 3 so that's us you can see when I hit the mic you can see it come up now what you want to do is you want to as I'm talking right now you can see over here you can see this going up and down so as I'm talking right now I'm at this level I'm at about 10 so what you want to do is you want to adjust the gain on here to about zero and then you don't want to do it just up check check check but you see how it spikes up now obviously when I go put you to Anna that's going to be a spike but check check hard that's kind of where you want it right now even though it's not at zero at a time as a singer gets louder it goes up and you don't want to go into the red so that's a good level right now so we got the gain structure in here so we're basically what we're doing is we're getting the highest cleanest signal out of this microphone into the sports that's top level next is you adjust the level so we're going to mute this take the brake switch off next we want to get this level up so check one two two two again we've got about a little under unity and unity gain means so you don't add you don't subtract unity gain is either zero or sometimes it's you or sometimes it's an infinity symbol it is basically you're not adding you're not taking away and that's where you want to kind of be again we're on we're on three here so we're way below unity gain so we want to take this up it's about right there so we have a little bit of room check one two two two and it's about perfect so if I check hard it goes up past unity gain if I go low if I'm just talking like this it's below but that's fine because again you want to compensate for louder you know people are going to sing louder and lower and louder and lower and a few of a guy running he can fix that real time but you if you don't have somebody running the board you can't and a guitar and stuff is a more level output so now we got the game structure set correctly on the board we have the maximum amount of signal coming out of here we're pulling the maximum amount of signal out of the microphone we have the maximum amount of signal coming out of the channel and we got the maximum amount of signal coming out of the main board and we got a little bit of room we could go a little better but you always want to leave a little bit of room so if it gets more packed in location or you get more people or you just need a little more volume you know won't always be maxed out but at this point we're getting to maximum out of headroom out of this board and not you know so the amplifiers can work a lot less so I'm going to pause it here and move down some pain flyers now we're at the second part of our video the first part we got the maximum amount of signal coming out of the board now at this point I don't have the EQ set up right now but if you did we're using EQ because it's just a practice setup at the house but a live setting you're using EQ now you don't want to really add gain in your EQ or if you have any other processors if you have a feedback controller a crossover and that kind of equipment you don't want to add or subtract from your signal at that point you've got your maximum Headroom coming out of your mixer at this point you want to try to just maintain that so if your EQ adds a little bit of output you may want to cut it it has a level out or if you're taking away a little bit you want to add a little bit you've got one again you want to keep it about level at that point so here's where then the beauty of this is the amplifier is on and these are sensitivity knobs are not volume nomes but in this gain structure they are volume knobs what because you got your maximum signal coming out of your board these amplifiers are getting a unity gain input meaning they're getting their maximum amount of headroom in here so if we just turn this up a little bit the sensitivity check one two two two two just that little bit it's already pretty loud because and there's no noise no noise coming through the speakers at all because on the mixer the mixer has already a full outlet you know you're getting them as much output as you can so you're going to get a lot less feedback you're going to blow a lot less speakers and it's amplifier is going to run a lot easier because you're not cranked and you're not going to hear to assist hiss that hiss in the background and if there's is a pop or something the sensitivity is low enough that you probably aren't going to blow any speakers out and then what you do is use this basically for your volume knob for your show even though yeah it's a sense but you got your maximum amount of output you're coming out of the board so you can use this so you check 1 2 2 2 that might be good enough maybe you bump up here check 1 2 2 2 either way there you go that's how you set it up to get the proper game structure so if you have any questions let me know and like I said this is often mistakenly set up incorrectly and result is blown speakers hiss terrible sound because you're amplifying each one of these devices each cable adds a little bit of noise if you have the sensitivity up really high on your amplifier well guess what you're going to amplify that noise as well as your signal but because I have my maximum amount of signal Headroom coming out of my board and out of my device I don't have to amplify it up very much so thanks for watching my video I'm going to do one here on speaker placement which is probably just as important so this is part of my advanced videos on pro zone

Channel: World According To Jim

Views: 572,517

Rating: 4.6636882 out of 5

Keywords: live sound, pro sound, setting, pro, sound, pro audio, gain, mixer

Id: IJVdBTfpUEQ

Length: 9min 59sec (599 seconds)

Published: Sun Jan 06 2013