A potential new and better method for measuring transmission loss in the field

In a recent study, transmission loss (TL) measurements were made from outdoors-to-indoors and indoors-to-outdoors of a house. These results agree with one another within 0.6 dB. The agreement achieved in this recent study is believed to be because the indoor measurements for the indoor-to-outdoor TL were made at the party-wall surface of the reverberant space. This current paper demonstrates what amounts to a form of pressure doubling at the surfaces of the room containing the reverberant field. It is this higher level that must be used in the TL calculation from indoors-to-outdoors; not the reverberant field measured interior to the room. The actual increase in level for this reverberant-field pressure enhancement appears to be close to + 2.7 dB, which is consistent with measurements of free-field pressure doubling on a hard surface, which are theoretically + 6 dB, but typically measured to be + 5 to + 5.5 dB. This factor of + 2.7 dB for reverberant-field pressure doubling should be applicable to all mea...