Figure 3,--Instruments used in speaker calibration: (A) Signal generator, (B) VIT'VM, (C) elec- 
tronic switch, (D) McCue driver amplifier, (E) speaker calibration chamber, (F) sound level 
meter, (G) oscilloscope, and (H) frequency counter, 
SPEAKER 
DRIVER 
AMPL. 
OSCILLATOR 
MIC. AMPL. 
FREQUENCY 
COUNTER 
Figure 4,--Block diagram of instrumentation used in speaker calibration, 
4 
