I have a Boston acoustics pro 12.5 sub(4 ohms) in custom box at Boston specs (sealed 1” mdf).  It is rated at 1200w rms and iam now using a 600w rms(Hertz class D).  Although it sounds pretty good, cant help wondering how much difference a 1000-1200w amp would sound compared to the 600w amp.  Need advice from people with experience trying different amps with the same sub.  

It effectively takes a 3dB increase in power to hear a difference.  This is a doubling of power.  Unfortunately, you won't really gain much.  I gather from your post you are looking for more output.  Honestly, as great as that driver is, it's not much a beast in the way of sheer output.  It's a sealed driver only, so you're only other option is a larger enclosure at the sacrifice of power handling and cone control, so that just screws everything else. 

I agree with Ryan.  Might be a slight increase in output, but nothing major.  Only real benefit I can see is head room.  The larger amp could have the gains backed down and not work as hard therefore lower chance of clip.

Thanks for your replies....

in regards to gain setting, my HU is 6v so the gain is already set low , maybe 1/4 full or less (used DMM to set)

 

i just had to ask this question because most articles recommend to match amp power with rms rating of sub(or close to it). So I was never sure if I was hearing close to the full potential of this sub.  It only really comes alive when close to full volume, but I assume this is normal, at least with sealed boxes.

Don't bother setting gain with a DMM. Typically this method is too conservative. Play music and turn the gain up till you hear distortion. 

Another idea to try, move the subwoofer around in the vehicle. I've notice significant differences in output at the driver position by moving the enclosure closer or further away from the trunk lid, aiming, etc. 

Edited May 2, 20196 yr by lithium

Great point. I neglected possible cancellation issues.