Mackie MR524 or MR624 + alternative?

I have a good amplifier but want a more tight sound and more power (i use dali spektor 1 which for the money is very good, but rated at 82db that limits the dynmaic,power,punch bass, despite that the bass is very good).

Mackie MR524 or MR624

I have heard they are some of the better hiss free active studio monitors, so because of that,the price and the z review of the MR624, i want a pair over the adam T5V zeos also have reviewed

Is there any low hiss alternative ?