same gain setting from 4 ohms to 2

[maddmatt02 0]

alright, my girlfriends car has a rf 300.1 to a rf punch P2 12. single 4 ohm(not sure why the place let her buy that combo, 150Wx1@4ohm)

I bought a new sub for her birthday, just a resonant engineering REX 12 dual 4. nothing special but it will be getting twice the power at least. it is a ~2.5 ft^3 ported box tuned to 28 I think it was, that I built for her a while back, and I still need to carpet it.

RE

I havent told her that I got the sub for her, and dont want to tell her. I planned on in the middle of the night going out and pulling the box, carpeting it, and dropping in the RE. obviously I wont be able to bump the system in the middle of the night. I want her to turn it on on her way to work and just wonder why its louder(box is in trunk, she wont see it)

right now I have the bass boost on the deck at just +1, bass boost on the amp I dont even think I have up, and if I do, no more than 1/8-1/4 of its knob movement. I cant remember at all where I set the low pass at, and there is no SSF.

I have the gain set lower than it could be, it sounds clean on everything right now, most stuff was clean with it higher but some songs just sounded wrong so I turned it back down a bit.

so after all that my question is will it be safe to leave all the settings and put the RE in and not have a chance of it blowing the new sub?

[maddmatt02 0]

well, sub gets here the 2nd according to fedex. I got a dmm today and am downloading some test tones right now and Ill just set the gain using the dmm and try a number of tones and see what setting is best.

I know the sub says its rated at 175w rms, which isnt what the amps rated to do at this ohm load, but it is more than its rated for at the ohm load its seeing now.

what should be my goal?

if its rated to do 300x1, if Im only turning gain up to try and push 200 it should be nice and clean, right?

how tough are RE subs? auction says 175 rms/ 6-800 peak, although I have no idea where they got those numbers from, but hopefully it can at least handle ~200 watts.

so do I have it right, I want the dmm to show 20V AC because 200 wattsx2ohms = 400 and sqrt of 400 is 20?

the reccomended box on their site is 1.5 cubes at 35Hz. should I build that box? or will a 2.5cube at 28Hz be sound better? seems that thats tuned kinda high?

[KU40 173]

You shouldn't have to mess with the gain. The gain is used to match the incoming signal voltage from the head unit, which won't be changing.

[maddmatt02 0]

so if the amp was giving the current sub 150 watts, and I dont turn it down, ill be giving the RE 300 watts, right? isnt that too much for the sub or should it be fine?

[KU40 173]

If it is too much for the sub, turn the gain down. Simple.

[maddmatt02 0]

alright, but I got it for my girlfriend as part of her birthday present. someone at the shop let her buy a ohm sub for that amp, which isnt as big a deal if it was a bigger amp. but I havent told her, I planned on going out in the middle of the night and put it in the box without her knowing so that she just wonders why its louder on her way to work the next day.

Ill just wait until the day after I get it and take her car "to the store" but really just go down the road and drop it in so I can listen to it first and make sure nothings out of the ordinary.