Three things are needed to accurately set your gain on your amplifier using a digital multi-meter. This is a great way to set your gain so you are not sending a clipped signal to your speakers.

First thing - Decent DMM with ability to test for AC current.
Second thing - Test tone CD or CD with 50 hz multiple times on it.(easiest way is to just download it a bunch of times, or just copy it in the folder on your PC.
Third thing is your amplifier output voltage you can calculate it here on this easy calculator. All you need is the power (RMS) that your amplifier puts out, and the reistance at shich it does it. ex. 500 watts at 2 ohms
Amp output voltage calculator



Set all of your Head Units contols to zero,(like bass, treble, any bass enhancements)
Turn your gain on your amplifer down to zero.

Set your DMM to AC
Connect your DMM to speaker outputs on the Amplifier (using + and - terminals on your amp and your DMM)
Put the Test tone cd in your HU and turn to 3/4 volume (or about as loud as you will listen to it.)
Now turn your gain up slowly until you reach your output voltage found earlier.

If you want to add those bass enhancements and such, when you find your correct gain setting, turn it back down some, that way you do not send unclean power to your amp and then onto your speakers.

If you have any questions on this, please PM me

 

I smell a sticky.

 

Agree, however depending on what type of amp you'retrying to accuratelyto set the gains for you will need diffrent hz testing tracks.

 

very ture. a 50hz tone will only work for sub amps. I like to use pink noise. That way, all amps are covered by the same track.

 

can somebody explain GAIN to me? logarithms have never been my strong point so decibels are also a little troubling.

according to the calc above, i need an output voltage of 37.8V. when i listen to my music, i usually use the preset eq's and im almost always using "superbass" "powerful" or "vocal". if i set the gain at a flat eq with no bass enhancements, what will it sound like when i change the headunit controls? can it hurt the amp?

also, my amp came with a "bass control" ****. what exactly does it control? is it just a master volume control for the amp or dose it have anything to do with gain?


thanks for any help. im trying not to annoy you with all of my noob questions about this kind of stuff but i always try and research and understand everything before actually doing it

 

bump

i dont think anyone saw my post. it doesnt seem like new messages show up on sticky threads

 

ah, I just saw this.

here is a pretty good explanation on gain.

http://www.bcae1.com/gaincon2.htm

What you are doing with adding bass eq's and such is sending dirty signal to your amp. I wish that I could disable all eq functions on a customers car, because, then they cannot blow their sub. The **** depends on the amp. some are a remote gain, meaning that it changes the input, bad

Most these days are just a bassknob. Turn it up, it will max out tot he point that your gain on the amp is set. Turn it down, basslevel decreases, but the amp setting stay the same.

 

thanks, that link cleared up a lot of info. so you think i should leave all of the bass/amp controls alone? i dont always want to listen to thundering bass. sometimes i just want to listen to my music normally, what should i do in this case? normally i would change it to "vocal" mode ( less bass, higher mids and sorta high tweets). but if changing the eq can be harmful to the amp ill try not to do it

 

ther is more to it then that if u want to get really tech happy. get an O scope and test for a clean signal on the head unit for the max volume with a clean signal. then disconect the speakers hook up the Oscope to the amp and with the headunit set to the max clean output scope the amp turning it up till the signal is dirty then back it down till its clean then check the voltage on the amp. remember the max volume on the head unit and the voltage out put on the amp. thats the way mine is set up and when u run alot of power a clean signal is definatly a requirement. the gain on an amp is just there to match the power from the headunit to get a clean signal it will make it louder by turning it up but only at lower volumes so when u turn the headunit up with the gains all the way up on the amp your just going to make the coils in your woofer hott. hope that helps

 

The purpose of the gain is to match the signal volts RMS coming from the source (CD player, etc.) to the input of the amp for correct power matching and to reduce clipping.

Here is a guide that will help you set the gain correctly http://www.box.net/shared/uchv4dbk88

You'll need a multi-meter (AC voltmeter, $15 from Radio$hack), Microsoft Excel and a way to burn an audio CD from an MP3.

If you don't have Excel, use this link http://www.box.net/shared/nkkw1dhk4g

See my site for more info http://spkrbox1.spaces.live.com