"STC" does NOT translate to today's version of "real life" - it was developed for SPEECH isolation, not MUSIC, so it doesn't even CONSIDER anything below 125 hZ, and is centered around 500 hZ. Drums and bass have their main energy at or below the lowest frequency band that's even mentioned in STC calculation.
The human ear requires approximately 45 dB to hear frequencies at 50 hZ; (this value changes depending on whose study you look at)
http://www.phys.unsw.edu.au/~jw/dB.html
Scroll down to the heading, Loudness, phons and sones
Just below that, there is a chart of equal loudness values - note the lowest curve on the graph, called "Threshold of Audibility" -
so 40 dB of TL at 50 hZ means that your sound level inside the room would have to be 85 dB at 50 hZ before a person standing right outside the wall would hear it at all. 110 dB (inside) at that low frequency would be a fairly low level sound outside, and probably wouldn't be audible by the time it gets to the property line, unless the houses are crammed together within 5-10 feet of each other; even then, if windows are closed in the neighboring houses I doubt they would hear anything... Steve
MASS-AIR-MASS Question
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Julián Fernández
- Posts: 128
- Joined: Sat Oct 09, 2004 3:23 am
- Location: Buenos Aires, Argentina
