If all of this is over whelming set the gain to 4v

Grab a DMM, play a 50hz or so test tone and measure the voltage output (set the meter to AC Volts) of the subwoofer RCA output on the headunit with the volume about 80% of the way up. Disconnect the RCA from the sub amp and put the positive DMM lead on the inner nipple (yes, I said nipple) and the negative DMM lead on the outer ring.

Ok, I'll grab a DMM and will do that.

I'll let you konw the results !

Tell me everything !

I can sold my old amp to a very good price, as always, so I did not spend too much money on this amp !! No problem for that. I work for my money, and I keep my eyes opened to make money !!!

My concern was about the amp, but it works fine.

Impious, I will mesure with a DMM, but when I think about it, I'm pretty sure the 4v rating is with the bass level to the max !

As a manufacturer it's what I would have done.

If you rate it at 4 volts when level at 0 , what voltage would they find with the level up ? More than 4 v ; so it must be 4v at max level. I can be wrong !

In résumé, I have one thing to do : mesure the voltage from the hu rca. and tell you the results. I'll buy a DMM today or tomorrow afternoon when I go

It will be easier to mesure at the back, on the rca's just before the bass amp. the h u is really hard to take off to access the rca's.

OP: The jump from the 1500 to the 3000 should be very noticeable. No matter what power you're getting out of the 3k, you were roughly getting the same ratio out of the 1.5k. Look at it this way, assuming you are wired to one ohm.

I DO NOT KNOW THE RATED SPECS FOR SUNDOWN AMPS, THIS IS ALL A GUESSTIMATE:

Saz1500, starting impedance 1 ohm, rise to 2 ohms, drop to 13.5 volts, you'd get 700 watts.

Saz3000, starting impedance 1 ohm, rise to around 2.1 ohms (more heat), drop to 13.0 volts, you'd see around 1400 watts. That's still double in power which should be a 2-3db gain. I'd say closer to 3 due to the fact that you're not maxing out the BTLs limits with that power at all. 3 db is a pretty decent gain to the ear.

I went from a AQ1200d to the AQ 3500.1d. I metered a 137.5 with the AQ1200d, and (with new alt), soon to do a mid 144 with the AQ 3500.1, the 144 is not a guess, I did a 143.8db outside of my car, inside will gain me around half a db. But, I'm only clamping a little over 1kw from my AQ 3500.1. In the same box, it is safe to say my rise with the AQ1200 was similar to my rise with the AQ3500.1.

Same everything but different amps, I saw exactly a 7.3db gain, and I'll tell ya, that was extremely noticeable to the ear. Assuming your box is the same, voltage drop a little more (should be, double in power), to the ear it should be fairly louder.

OK guys,

I did not buy the DMM yet, but I turned up the bass level on the head unit to (to +6), and NOW I can use the gain knoob right !!! I can set the gain easily now : when I turn it up, I can really hear the sub bottoming out (I think it's the right word, not sure), or making a weird noise. I know where to set the gain now.

I still need some times to adjust the settings, but the DMM will help me do that right.

I'm happy, now : more power, more bass, more everything !!!

Thanks for your help.

I'll will post the voltages I get, with the DMM.