How to TUNE Car Amplifier & Set Gains

what's going on welcome to this amplifier gain setting video in this video i'm going to show you exactly how to set the gains on all of your components and in my case i have a line-up converter i have an inline amplifier that's driving my indoor speakers and i have an amplifier driving a 10 inch sub each of these components has its own individual gain settings i believe that if you understand what gain is you're going to be better prepared to troubleshoot the system if something goes wrong gain is your sensitivity adjustment for the amplifiers the gain is going to tell the amplifier how sensitive it needs to be for the signal that it's getting let's pretend that you set out one day to make your own head unit and make your own amplifier you build your head unit to put out a very specific voltage and you have the luxury of knowing exactly what that voltage is so when you go to engineer your amplifier you're using that exact knowledge of that voltage to set the internal gain of the amplifier so that it puts out the power that the amplifier is supposed to put out cleanly at that level so whatever your head unit that you made up maxes out at in terms of voltage you can set your amplifier to max out in terms of power at that voltage so when you build this hypothetical amplifier and head unit you don't have to put a gain dial on the amplifier because you already said the internal gain of the amplifier because you know exactly what those numbers were and you built that amplifier only for that head unit but let's say that now you want to build an amplifier that you can mass produce and sell millions of it well now things are different because now you're not going to know exactly what voltage is going to be fed to that amplifier so your amplifier very well could over amplify a signal that it gets or it could be too weak if the signal that that amplifier gets is considerably weaker than the signal that you originally designed it with so you being a smart engineer your solution to this problem is to put a gain adjustment on the amplifier and that gain adjustment is going to allow your customers to set that gain themselves so by allowing your customers to set the gain properly they can still make use of the maximum power output of your amplifier for whatever components that they are driving this amplifier right here is rated for 500 watts rms when it's presented a 2 um load and it has an input sensitivity of maximum of 4 volts if i feed this amplifier a 4 volt signal then i can get 500 watts rms out of the amplifier if i have a 2 ohm subwoofer attached to it that's your maximum level so knowing that this amplifier right here can take that 4 volts and convert it into 500 watts rms i want to make sure that i'm feeding this amplifier as close to those four volts as i can get if i'm feeding it a considerably weaker signal i'm going to be forced to turn the gain up and when you turn the gain up you're also amplifying noise so you want to make sure that you don't have to turn the gain up very much keeping in mind that if you exceed the maximum input sensitivity of the amplifier the amplifier will start clipping and distorting the signal it's not going to make more power than what it's rated for it's simply going to send a very crappy signal to your speakers and it's going to get hot and it's going to probably damage the speakers or damage itself so if this amplifier had the gain internally set to give me a maximum power output at four volts i'm never going to be able to get the maximum out of it if my head unit is only feeding it say three volts but since i have the gain what i'm essentially doing is telling the amplifier that instead of making maximum power at four volts make it at three volts so let's take a closer look at what's going on here so here we have my line out converter the lineup converter is taking the speaker level inputs right here from the factory head unit so these are the cables that are coming straight out of the head unit that normally would be plugged into the speakers the amplifiers are made to work with a low pre-amplified voltage this voltage right here is already amplified because it's meant to drive speakers i want to bump that down so that the amplifiers do the amplification and not the head unit i already did a video going over all the features of the lc7i so check out that video so you can see exactly what's going on and why i chose to do that but just know that this lineup converter is an active lineup converter that is taking these high speaker level inputs and it's outputting a low level signal this lineup converter right here has the ability to put out 8.5 volt max 8.5 volts is actually a pretty high voltage neither of these amplifiers are made to work with a voltage that high in fact this amplifier has an input sensitivity maximum of 4 volts and this inline amplifier right here is actually even lower at 2.8 volts rms so what i want to do is to adjust these three channels right here so that they don't put out more voltage than what the input of these two amplifiers is i'm actually going to make sure that the output here is as strong as it can be so i want to get as close to 4 volts and as close to 2.8 volts as i can here when i set my gains the higher your source voltage coming in the less sensitive that your amplifiers have to be and that means that you're going to cut down considerably on noise and your system is just going to sound better so to set the gains as i'm going to show you you're going to need a multimeter i think i bought this at either lowe's or home depot and they are very cheap there's really no excuse not to have one of these if you want to set this properly the only thing that you have to ensure is that the multimeter reads voltage ac so if you get one like this it might seem complicated it's really not the numbers just denote the range on the screen that it's going to show you so basically where the decimal point is going to be and another thing that i recommend is that you make yourself something like this if you see right here all i did was take a rca cable that i had laying around and i exposed the leads and that just allows me to put the leads of the multimeter right to it very easily so that i can just unplug these down here and plug this in and i can take the reading without having to put the leads of the multimeter directly on there which can get a little screwy so we've reached the point where you're going to have to make a creative decision in this process in order to set the gains of your amplifiers you're going to need test tones and the test stones are going to allow you to set the gains in a controlled way because music is very dynamic and it has highs and lows so if you're measuring music with a voltage meter it's not going to work because it's going to just jump around and it's not going to be useful so we use that test tone that reference voltage because it's going to give you a solid voltage that you can manipulate and actually monitor through the multimeter if you're setting an amplifier that is meant to drive a subwoofer you know that that amplifier is only going to be playing very low frequencies so the test tone for that particular amplifier has to be 40 50 or 60 hertz so in my case i'm using a 40 hertz test tone for that particular amplifier now my inline amplifier right here that's meant to reproduce the full range of frequencies that the music has so for that amplifier i'm not going to use 40 hertz i'm actually going to use one kilohertz which is more representative of the kinds of frequencies that that particular amplifier is going to be reproducing if you look around the web on other videos and even on most websites most tutorials are going to tell you to use a zero decibel test tone and zero decibels is the baseline it's the highest level that music is recorded at so by using a zero decibel test tone you're actually setting up your amplifiers for the worst case scenario now that's theoretical right that's the perfect scenario a perfectly sampled piece of music that's recorded at a zero decibel level if you set it with zero decibels your amplifiers are gonna play great they're gonna give you maximum power and they're never gonna clip however reality is different and music is recorded at very different levels personally i like listening to a lot of 90s music that it's not the best quality and in those cases i know for a fact that music is nowhere near that zero decibel level so if i'm setting my amplifiers with that zero decibel source i'm leaving a lot on the table so i have to crank up the volume to get that full experience out of the music way more than i normally would whereas if i set my gains with a negative five decibel level i can actually reach fullness and richness in the music at a much lower volume and it just sounds so much better and i can really get the most out of my equipment but that's the reason why i went with negative five deaths some people actually go with negative 10 decibels i wouldn't go that crazy i think negative five is a good compromise but know that if you go negative five if you start listening to music that is recorded at a very high level at that zero decibel mark and you crank up your volume then you might start distorting the music so the first thing i'm going to do is actually i'm going to disconnect all the outputs off of this line out converter because this is going to be the first component that i am going to set and i don't want this sending a hot signal to my amplifiers i don't need the amplifiers plugged in for this portion so i'm going to go ahead and unplug all of these before i even turn it on so because i'm setting the lineup converter first i want to make sure that these are all minimized so i'm going to minimize the gain adjustments on each of these all the way to the lowest position so that's all i'm doing counterclockwise all the way this particular line of converter has accubase which is base restoration for rolled off base and this is their default position so i'm not going to lower these i'm going to leave those right there in the middle so i'm going to go ahead and set the gain for channel 3 first and channel 3 is going to be this amplifier right here that's driving my subwoofer so i'm going to play the 40 hertz negative 5 decibel tone and i'm just going to put it on replay so that it's continuously sending that negative five decibel tone through the speaker leads right here into the lineup converter and i'm expecting the lineup converter to take those high voltages and reduce them right here to a more appropriate voltage if you remember this amplifier right here maxes out at four volts so i'm looking for four volts out of here i'm gonna go ahead and plug in my homemade rca cable here to one of the ports it doesn't really matter which one just pick one and plug it into it okay so the car is on and the head unit is playing that 40 hertz tone at negative five decibels my volume is set to 75 percent of its max my equalizer settings are flat and the speed volume and all that extra stuff is turned off so now it's time to actually read what we're having here and set our output level is super easy all we're doing is turning on our multimeter to read voltage ac right now we're reading zero volts out of that output right there so i'm gonna go ahead and simply turn this up until i get to four volts okay i went past it four volts so i'm good if you notice right here this particular lineup converter has a maximized light that allows you to set the gains out of the lineup converter just by sight and use that maximized light and that's telling you when the output of the lineup converter is starting to get distorted the maximized light i'm going to go ahead and ignore it and the reason why i'm ignoring it is because that maximized light is actually meant for music and because i'm not playing music through it i'm playing a tone the tone is way more likely to maximize the output of this lineup converter than regular music is so right now if i was playing regular music that maximized light would probably be blinking so right now at 75 volume i am outputting no more than four volts out of that right there i know now that when i set the gains of the amplifier that i am not going to be feeding it a signal that it is not meant to reproduce and i'm not going to be clipping so now that we have our head unit playing that thousand hertz at negative five decibels i'm gonna go ahead and move this over to channel two right here and i'm gonna set the gains of my front speakers again i'm reading zero so i'm simply going to increase the gain right there the voltage that we're looking for for this amplifier is 2.8 volts so i don't want to go over 2.8 volts on this output right here it's a very fine adjustment so 3 volts is fine it's close enough now i'm going to go ahead and set the rear gain right here and now i'm going to go ahead and increase it until i see 2.8 okay the output settings of my lineup converter are perfect and as high as i can go before hitting my amplifiers that's going to ensure that i only have to raise the gain on these amplifiers the minimum amount to get the proper wattage that i want out of them so let's move on to doing that for this next step i actually do want to send the signal from the lineup converter to the amplifier we're going to be setting the gain of my main amplifier right here that's driving my subwoofer i don't want the subwoofer connected for this next step these two cables right here are going out to the subwoofer and the trunk so i'm going to go ahead and just disconnect them and i'm going to go ahead and plug the amplifier back to where it goes so the first step is going to be turning our gain all the way down so we want it as low as it goes i'm going to keep the phase at zero the frequency in hertz i'm not as concerned about that you can go ahead and put that somewhere in the middle but this is just your low pass filter right here the punch equalizer i think it adds fake bass to to the system it just doesn't sound right so make sure that that's turned all the way off if you have a remote punch level right here this is just a remote gain adjustment whatever you set your gain to your maximum gain to right here the maximum level on the knob is gonna denote that you have two options to do this you can either just unplug it and set your gains that way or you can go to the actual remote punch knob and set it to maximum gain that way the reading that you get out of here is accurate i have the volume set to 75 percent and i have that negative five decibel 40 hertz tone going through the system right now coming out of here and going to the amplifier so to find your target voltage is actually quite easy pull up the calculator on your phone and then go ahead and access the scientific calculator within it i'm going to go ahead and do that right there so this is the scientific calculator right here so to find your target voltage all you have to do is find the square root of your amplifier's maximum rms power multiplied by the resistance of the subwoofer that you're going to attach to it that's only the case if you're actually matching your amplifier and your subwoofer if you happen to have a subwoofer that puts out less power than the amplifier that you're attaching to it then you're going to use the maximum rms power output of your sub in my case i'm using a 500 watt rms amplifier and i'm mating that with a 500 watt rms subwoofer so what i'm going to do is i'm going to click the square root symbol right there and then i'm going to multiply 500 the impedance of my subwoofer is 2 ohms so i'm going to multiply that by 2 and that's going to give me my target voltage which is 31.6 volts so you take this reading right at the terminal let's see what i got okay so i'm over and i am already at the minimum gain so what i can do in this case is just turn down the output level on the lineup converter a little bit which is what i'm doing right now to get that voltage to what it needs to be which is 31.6 it's a very very fine adjustment and even a small movement over here makes it jump quite a bit so 31.5 whatever it is right now the 1.4 i'm happy with that so i can consider the gain set properly on this amplifier based on my taste so setting the gains on the inline amplifier right here is a little bit different because we cannot unplug the speakers off of it in order to do gain settings like we did on this amplifier right here so the first step is turning down the gain adjustment on both channels the rear and the front i'm going to go ahead and disconnect all of the outputs from the lineup converter and i'm going to set one channel at a time so first i'm going to do the front speakers so i'm just going to plug in the front speakers now with the front speakers plugged in we have to start playing a signal through the system and because we're not messing with multimeters to set the gains of this amplifier right here we're going to need to find a music source so you want to make sure that whatever you play is a very high quality when you're setting the gains the first step is actually turning up the volume on your head unit until you hear distortion and then backing off until the distortion goes away in some head units you could actually max out the volume before you hear distortion so you might actually not hear distortion at all i'm going to go ahead and turn up the music so it's probably going to get a little loud here for a split second and then i'm going to turn up the gain on the amplifier while the music is up until i hear distortion and then i'm going to back it away okay i don't know if the microphone picked that up but i could definitely hear the distortion when i turned up the gain too high so i went ahead and backed it up and now i know that my front channels are good i'm going to do the same thing with the rear channels now [Music] all right so again i could definitely clearly hear the distortion there when i went too far and i backed it up so now theoretically speaking my gains should be um pretty good so i do want to mention something about this inline amplifier right here this inline amplifier has a high pass filter you can see them right there so because we're not driving subwoofers with this inline amplifier right here i don't want to send very low frequencies to my speakers that could possibly damage it because the speakers are not meant to reproduce sub bass frequencies that's what the subwoofer is for so what i want to do is actually set the high pass filter above the minimum that my speakers play you can look up the specifications of the speakers that you have installed in your car and just go above it i have mine right now set to 80 hertz so now all the gains are set and all of my components and now we have to make sure that everything is working exactly as we intend it to so what you have to do get yourself some music that you like to listen to and then we're going to crank up the volume and see what it sounds like when all the components are working together and i'm hoping that it sounds great so let's do that right now [Music] sounds great i don't know if you can hear me but it sounds fantastic it sounds great it actually sounds fantastic i was right on the mark with all the gains that i set i just had it you know 75 volume and you know i don't usually go you know any more than that anyways and i didn't detect any sort of clipping or distortion of any kind it sounded clean throughout the sub is perfectly balanced with the system and i of course retain the option of turning down the gain if i happen to be playing a song that is really really bass heavy so that's exactly what you want out of your system when you're done i've done this several times and it works it's basically a foolproof method of doing this if you use a zero decibel tone then it's still gonna sound good but it's gonna be a lot lower you might not get everything out of your equipment and you might have to turn up the volume quite a bit to actually feel the system really come alive so that's why i don't like setting it with zero decibels i'm gonna go ahead and wrap all this up put my car back together and move on to the next video thank you so much for watching i hope you got something out of this if you still have questions ask them in the comment section and i'll see you next video take care

Channel: Boost & Shutter

Views: 391,624

Keywords: how to set amp gain, how to set amps gain, how to set amp gains, how to tune amp, how to tune amplifier, amplifier tuning, amplifier tunning, input sensitivity, how to set input sensitivity, how to tune an amplifier, how to tune an amp, amplifier gain settings, how to tune car amp

Id: B5UYKw9j33Q

Length: 19min 50sec (1190 seconds)

Published: Thu Sep 24 2020