Sub not getting enough power

[IvanIsRock]

I have a American Bass XFL 1222 with a Taramp HD2000 and I am struggling to get the sub bumping. I used the multimeter to tune it with a 50 hz test tone at 0db with the head unit at 75%ish (stock head unit).

 

For the break in i am running it low for a bit to be safe, the first tune i was giving it 21V, then that wasnt loud enough in my opinion so i got it to 26V. That still didnt sound loud so I finally cranked it to 31V and it is still not loud. I know it should be at around 39V for 1500RMS but I know what a 750 RMS sub sounds like and that is no where near it while at the same voltage. (around 22V). My friends sub is a 800W RMS sub and he is running it at arround 24V and it is way louder. So i think i must be doing something wrong. 

 

I did some reading and thought maybe I should use a -5db test tone instead. I tried that but it did not reach the voltage that I wanted it to. 

 

Here are the max voltages I was outputting for my amp 

60hz -5db : 35.6V

50Hz -5db : 26.8V

40Hz -5db : 17.9V

 

60hz 0db : 51.2V

50Hz 0db : 39.4V

40Hz 0db : 26.1V

 

If I am using a -5db test tone shouldnt the voltage be set the same as I would with a 0db tone which would make the sub louder.

ie: 21V 0db = 21V -5db

 

I have no clue why it is so quiet. I wired the sub (DVC 2ohm) to 1 ohm for the amp and expected atleast 31V to be at a good loudness (louder then my friends 850W sub) but i was wrong.

 

theory 1 - Maybe the line out converter needs to be ajusted for. Never had to adjust this one for any other system. 

 

theory 2 - Maybe the DMM is not reading it acuratly but I dont think it will be that off to the point where 31V sounds like 10V output in my friends sub.

I am gonna order a O-Scope to see if that is my issue.

 

 

If anyone has any ideas please let me know as I want to get the sub booming ASAP.