G.R.A.S. Type 40HT Instruction Manual page 7

14
12
10
8
6
4
2
0
- 2
- 4
- 6
- 8
100 Hz
Fig. 1.5 Free-field corrections for various angles of incidence on the ½-inch Microphone Type 40AH.
Fig. 1.6 Typical noise floor of Type 40HT for system and microphone. Shown in ⅓-octave bands for
both the linear and A-weighted cases
0 º
90 º
1 kHz
Single-channel Low-noise Measuring System consisting of: Type 40HT and Type 12HF - Page 7
G.R.A.S. Sound & Vibration
0 º
30 º
120 º
60 º
150 º
180 º
90 º
Random incidence
120 º
10 kHz 100 kHz