VELOCITY MICROPHONES 



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cent of the measured directional characteristics. However, the discrep- 

 ancy between the measured directional characteristics of a ribbon in a cir- 

 cular baffle and the theoretical directional characteristic of a doublet or 



Fig. 9.20. Measured directional characteristics of a ribbon microphone with a large circular 

 baffle (see Fig. 9.17) as a function of the radius of the baffle and the wavelength. The 

 polar graph depicts the output, in volts, as a function of the angle, in degrees. The max- 

 imum response is arbitrarily chosen as unity. 



Fig. 9.21. Computed directional characteristics of a ribbon microphone with a large circular 

 baffle (see Fig. 9.17) as a function of the radius of the baffle and the wavelength. The polar 

 graph depicts the output, in volts, as a function of the angle, in degrees. The maximum 

 response is arbitrarily chosen as unity. 



pressure gradient system is very large for values of R/\ greater than f . 



The phase between the actuating force, equation 9.45, and the particle 



velocity in a plane wave, for a ribbon microphone with a circular baffle, is 



