Sub not the same volume as voltage

[IvanIsRock]

I just bought a 1500rms American Bass XFL1222 and built a box for it. For the longest time I was listening to my friends sub which is a 800rms Skar Audio SVR-12 and it’s always at full volume.

 

On the amp for the skar sub it measures 23V and on the amp for the American bass sub i set the gain to around 23V for break in which is around 750-800W (arround half of 1500RMS). I assume since both amps are outputting the same voltage to the subs they should be the same loudness. But no. Then American bass sub is not nearly as loud as the skar audio sub at 23V.

is this because the sub is rated for higher rms so it is not outputting the same as the skar sub, even tho they r both at 23V but the American bass is only pushing half the recommended power?

 

please leave your suggestions or comments.

thanks