I have no idea what the decibels are, I don't have the equipment to test it, but I have an 840 watt amp powering Kenwood Excelon speakers and two JL subwoofers. I haven't gotten the volume level over 70% yet, it starts to hurt your ears at that point unless the windows are rolled down lol.
And then when get old you spend $5k on hearing aids, mind you that was from other stuff, not stereos
I do a DB meter , but I have never checked my radio. Load enough.
BTW my girl has Tinnitus, from Milt . service, and a fall, It has put her in the hospital 2-3 times, do not mess with that.
BTW The watts marked on the box does not mean much. The best amp I ever installed was rated at 90 watts RMS . 5000watts