STANDARD VOLUME INDICATOR AND REFERENCE LEVEL 121 



It is evident that the instrument scale should be easy to read in order 

 that the peak reached by the needle under the impetus of a given 

 impulse may be accurately determined. The instrument scale, there- 

 fore, should be as large as practical since in the case of the broadcast 

 and motion picture applications, attention is divided between the 

 action in the studio and the volume indicator. 



The instrument scale graduations should convey a meaning, if 

 possible, even to those not technically inclined but who are, neverthe- 

 less, concerned with the production of the program material. 



Finally, the scale must be properly illuminated so that the relative 

 light intensity on the face of the instrument is comparable to that on 

 the sound stage. Unless this condition prevails, the eye will have 

 difficulty in accommodating itself with sufficient rapidity to the changes 

 in illumination as the technician glances back and forth from the 

 studio to the volume-indicator instrument. 



Existing Scales 

 The volume-indicator scales most commonly employed in the past 

 are shown in Figs. 12, 13, 14 and 15. It is evident that all these scales 

 differ from each other in one or more respects. 



Fig. 12— Scale on 203C volume indicator. 



The color combinations employed for the scale shown in Fig. 12 and 

 the simplicity of its markings are outstanding virtues. The division 

 markings and the numerals of the main scale are black on a yellow 



