Well the BEST way to set gains is with an oscilloscope. Lacking that, the second best way is with a test CD, and a DMM.
I am going to assume you don't have an o-scope, so I will give you the procedure for setting it with a DMM. I will need to know what model the speakers are. Get back to me with that, and I will walk you through it.
Well since you have 2 speakers, I am going to assume they are ran parallel and both have a nominal 4 ohm rating. So the total ohms the amp will see is 2 ohms.
The formula we need is Voltage(V)= equals the square root of wattage(P)xResistance(R)
So now we know we need 40 Volts coming from our amp, into the 2 ohm load, to equal 800 watts(400 per speaker).
Now take a CD with a test tone at 50 or 60 Hz at 0db, and play it on repeat at 75/80% of your max volume on your deck. disconnect your subs, and take your DMM set it to read AC voltage, put it the +(red) to the + on the amp, and vice versa for the -(black). Now turn up your gains on your amp until it says 40 volts, and your golden.
Hope that was helpful, If you need any clarification, just ask.
I would set the LPF no higher than 100 Hz.
I have done this on MANY amps, never have I ran accross , or heard of one that could not handle the brief amount of time it takes(under 10 minutes) to set your gains.
· 1 decade ago