VISIBLE PATTERNS OF SOUND? 
By RareH K. PoTTer 
Bell Telephone Laboratories 
[With 4 plates] 
The automatic representation of speech sounds by visible traces 
or symbols has long been a subject of interest to acousticians and 
phoneticians, and especially to those concerned with the development 
of electrical communication. Techniques for automatically record- 
ing the wave forms of sounds have been very highly developed; but 
there has remained unsolved, until recently, the problem of recording 
sounds in a manner permitting their ready visual interpretation and 
correlation with the auditory sense. An outstanding difficulty with 
the interpretation of the records of wave forms is the effect of phase 
relationships between fundamental and harmonics. These effects 
may produce a marked difference in the appearance of the wave forms 
of two sounds that are quite indistinguishable to the ear. Conse- 
quently, wave traces of even simple vowel sounds do not permit of easy 
identification by the eye. 
The facts are that wave traces contain too much information. To 
portray sound in a form that the eye can encompass in a glance re- 
quires that some means be provided for selecting the essential infor- 
mation and displaying it in an orderly fashion. A form of display 
that meets these requirements has been developed in the Bell Tele- 
phone Laboratories as described below. 
The work here described was begun before the war. Because of 
related war interests it was given official rating as a war project, and 
has progressed far enough during the war period to justify its being 
brought now to public attention. 
The possible uses of an automatic system for translating sound 
into patterns which may be readily interpreted by the eye are very 
numerous. It opens the prospect of some day enabling totally deaf 
or severely deafened persons to use the telephone and the radio or to 
carry on direct conversation by visual hearing. (The latter, in- 
1 Bell Telephone System Technical Publications, Monograph B-1368, Acoustics. Re- 
printed by permission from Science, vol. 102, November 9, 1945. 
199 
