184 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1932 



Table 1 contains a collection of loudness levels (rounded to the 

 nearest 5 decibels) of various noises as determined in this country 

 by the National Physical Laboratory and in the United States mainly 

 by the New York Noise Commission (the figure for the medium 

 frequency test note being selected). Certain points of general inter- 

 est are discussed below : 



Table 1 includes a variety of traffic noises both in London and 

 New York, and, as far as it may be possible to draw a fair com- 

 parison, it would seem that a street in New York is on the average 

 about 10 decibels noisier than a like street in London. Although 

 there are thoroughfares in London where at times a barking dog 

 would not be heard 20 feet away, there are traffic centers in New 

 York where, as the commission has pointed out, a tiger could roar 

 indefinitely without attracting the auditory attention of passers-by. 

 It is stated that certain street corners in New York are normally 

 noisier than anywhere so far discovered in the world ; for example, 

 the corner of Sixth Avenue and Thirty-fourth Street, which rejoices 

 in three main streets, three tramcar lines, a double-track line of the 

 elevated railway and the subway (underground). The arch sinner 

 is the elevated railway, and nothing, I imagine, is less likely than 

 that London will ever allow anything approximating to an overhead 

 railway to override its streets. 



The New York commission found that the ebb and flow of noise 

 from hour to hour closely parallels the density of the traffic, at any 

 rate up to a figure of 50 vehicles per minute. 



Some diminution of the traffic noise heard would naturally be 

 expected in the higher stories of a building, but the effect is largely 

 nullified, if there are high buildings on both sides of the street. 

 In such cases, even with skyscrapers, appreciable relief only comes 

 to the stories just above the first setback. Wise travelers book bed- 

 rooms on the twentieth floor upward in certain hotels in New 

 York and Chicago. 



Table 1. — Loudness levels of various noises 



TRAFFIC NOISES 



Source 



Very busy traffic, New York 



Very busy traffic, London --. 



Busy traffic. New York 



Busy traffic, London 



Quiet street, New York 



Quiet street, London 



Quiet residential street. New York. 



Quiet suburban street, London 



Quiet suburban garden, London 



Location or distance 



.\verftpo 

 decibels 

 above 

 thresh- 

 old 



Observer 



Free. 

 Davis, N 

 Free. 

 Davis, N 

 Free. 

 Davis, N 

 Free. 



Davis, N. P 

 Do. 



P. L.i 

 P. L. 



P. L. 



* National Physical Laboratory. 



