Scaling perceived loudness

Mr Niceguy's icon

Hello. Is there an algorithm that will scale the perceived loudness of a tone based upon the frequency? For example, I would like to slide the output of a cycle~ object from the lowest to the highest possible frequencies, and have the perceived loudness of the super bass frequencies equal to the perceived loudness of the highest frequencies. Thank you.

Bernd L's icon

don't blast your ears and your speakers...

you might have a look here:

https://cycling74.com/forums/equal-loudness-curves-implementation/

Mr Niceguy's icon

Hello. The wikipedia link Johan posted is a bit over my head, but I think I should be able to use that in combination with the discussion from Bernd to figure this out. I'll post my patch once I get this to work. Thanks guys!

Bernd L's icon

to get a clearer idea about the theory, you might have a look here:

and there is a lot of literature about this issue in the net.

ben sonic's icon

yeap. johan, your formula works quite nice.

Roman Thilenius's icon


is that F/M or R/D or is that 226:2003 already?


i am currently looking for the latter.

and btw., without any variables or constants for the base gain the formular seems pointless.

Roman Thilenius's icon

ok wikipedia says a-weighting is "based on" F/M @ 40 phon.

where can i find more and why was F/M the role model of something from 2003? (it shouldnt?)