sound volume between a vintage martin style 0 from 60's nad a koaloha opio spruce top

Hello

I was wondering

what is the difference, speaking about sound volume between a vintage martin style 0 from 60's and a koaloha opio spruce top soprano?

I have one vintage martin style 0, and it is very very loud. But i am reading everywhere the koaloha opio is very very loud too.

So maybe one of you had the chance to try both.