Larson Davis Spartan 821 - Page 54

Spartan 821/721 Manual Instrument Hardware Specifications A-7
A.1.4 Microphone Model 377B02 Filter Response and Corrections
Frequency response correction filters are available for each sound field/microphone type and for environmental
protection accessories. Note: “RI” indicates “Random Incidence” and “FF” indicates “Free Field.” The default
setting for this instrument is “FF:FF,” which provides the most accurate free-field response for this instrument with
or without the WS001 windscreen.
Figure A-3 allows for comparison of provided filter correction values. See the table footnotes for application
instructions. Figure A-4 through Figure A-10 describe each filter in detail.
FIGURE A-3 Filter Responses in Comparison
TABLE A.2 Correction Filter Shapes
Frequency FF:FF FF:RI 2116 FF:RI 2116 FF:FF 2116 FF:90
250 0.15 0.02 0.04 -0.31 0.13
315 0.14 0.01 0.03 -0.32 0.12
400 0.14 0.01 0.04 -0.35 0.12
500 0.12 0.01 0.03 -0.37 0.1
630 0.09 0.01 0.02 -0.43 0.08
800 0.06 0.01 0.01 -0.49 0.05
250 315 400 500 630 800
1000 1250 1600 2000 2500 3150 4000 5000 6300 8000
10000 12500 16000 20000
‐2
‐1
0
1
2
3
4
5
6
7
dBretoLevelat1000Hz
Frequency(Hz)
CorrectionFilterShapes
FF:FF FF:RI 2116FF:RI 2116FF:FF 2116FF:90