Setting gain by ear

[endofdays89 5,000+ posts]

Don't go based on what your headunit's stated preout voltage is...see for yourself. Or...just turn your gains up until it gets as loud as it can without clipping...If you truly can do that with your gains all the way up...you're probably getting no more than .5v max out of your HU's preouts, despite what it says.
You can use a dmm on your preouts the same way you would on an amp //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

exactly how is this done.

 

[SQL4Life 10+ year member]

now when you raise the frequency where the sub plays it definately gets alot louder but i am not sure how safe that is. Dunno if there is a frequency limit on where subs can play