This is a basic, non-axial Sabin calculator for RT60, the length of time in seconds it takes for a signal to drop 60db. For a recording studio, this should be about .20-.40s at 1000Hz, for a vocal boot it should be < .20s. A home theater or music room has slightly looser tolerances.
About Eric Oehler
Senior Engineer Founder and owner of Submersible Studios, Eric enjoys talking about microphones and buying audio software he doesn't especially need. He also spends an awful lot of time with a RTA and a reference mic trying to get the acoustics of the studio juuuust right.