Something like above baseline "276 Kilotons" along the line. However, I did mention sound attacks, which may seem to be a specific ability, but it is actually a general term for how all abilities in Hibiki are referred to. This means that his flame-based attacks are also sound attacks because they all contain purification sounds.
In the verse, stronger and more durable monsters can withstand sound attacks; for example, when Hibiki barely made a dent in
this monster and was forced to use the Ongekiko Bakuretsu Kaentsuzumi (24x amp technique) to destroy it, later he easily
one-shot them in Kurenai form. So you could imagine the level of Armed Hibiki, who casually
mowed down nearly everything that came at him.