ARCHITECTURAL ACOUSTICS 



By G; a. SUTHERLAND. M.A. 



University College, London 



The subject of the acoustics of public buildings is one of great 

 importance to the community, and merits the attention both 

 of the physicist and of the architect. In the past, at any rate 

 in this country, it seems to have received httle consideration 

 from either, and the punishment of having a large number of 

 halls which are acoustic horrors fits the crime of refusing to 

 investigate the problem or to make use of the information 

 made available by the work of others. 



The conclusions in earlier books on the subject are for the 

 most part not based on scientific theory or experiment. Some 

 of the principles laid down are right, but others are so evidently 

 arbitrary that all must be subjected to careful scrutiny before 

 any can be accepted as having adequate foundation. 



A case in point is the small manual of T. Roger Smith (i),* 

 first published in 1876, with a second edition, differing only 

 very slightly from the first, in 1895. This appears to be the 

 most recent work on the subject published in England, and 

 refers to the question as one which is confessedly obscure 

 and has been hut little studied. 



The book has merits. The author emphasises the value of 

 using heavy absorbent materials not only to prevent echoes, 

 but also to remedy excessive reverberation, and he appraises 

 the stretching of wires at its true value. But some of his rules 

 appear to be quite arbitrary and no explanation of their basis 

 is attempted, while others are based on an incomplete under- 

 standing of the mechanism of sound propagation. Thus the 

 acoustic excellence of the lecture theatre at the Royal Institu- 

 tion is attributed firstly to the fact that its height, depth, and 

 breadth are in the simple ratios of 2, 3, and 4. No reason 

 is adduced to show why such a simple relation should favour 

 good acoustics, and the slight discrepancies from these ratios 

 in the actual dimensions might equally well be responsible. 

 Further, the theatre is so much broken up by seats and the 

 gallery that it is very difficult to assign any meaning at all to 



^ The numbers refer to a list of original papers, etc., at the end of the 

 article, 



lot 



