Relation between the Normalized Impact Sound Level and Sound Transmission Loss

An expression relating the normalized impact sound level (Ln) and the sound transmission loss (TL) of a floor is derived. It takes into account both the resonant and the forced response of the floor, thus extending the utility of the formulas derived previously by Heckl and Rathe into the frequency range below the critical frequency. This relation between normalized impact sound level and sound transmission loss permits an experimental evaluation of the potential TL of a floor partition in the presence of certain types of flanking.