3M SP-DL-1, User Manual

Page: 141 / 168

Appendix A 128
Models SE and DL
Octave filters (optional)
Number of bands
~ Eleven bands, with center frequencies (f
c
) ranging from
16 Hz to 16 kHz. The octave filters are flat within < 0.3 dB in each passband.
The half-power points are at 0.707 f
c
and 1.414 f
c
.
Octave skirts
~ With respect to f
c
:
•
f
c
/2 frequencies
- Approximately 20 dB down.
•
2f
c
frequencies
- Approximately 30 dB down.
•
f
c
/10 frequencies
- Approximately 70 dB down.
•
10f
c
frequencies
- Approximately 95 dB down.
Third-octave filters (optional)
Number of bands
- Thirty-three bands, with center frequencies from 12.5 Hz
to 20 kHz. The 1/3 octave filters are flat within <0.3 dB in each passband.
The half-power points are at 0.89 f
c
and 1.12 f
c
.
Third-octave skirts
~ With respect to f
c
, the f
c
/2 and 2f
c
frequencies are both
approximately 50 dB down.
Instrument noise
Noise floor depends upon which microphone is being used. The following
measurements are for a typical instrument, with the 059-703 adapter (18 pF)
connected to the preamp and shorted at the BNC end. This condition closely
simulates the noise floor of a ½-inch microphone. For these measurements,
the instrument was set to the lowest range and to a slow response time.
• 22 dBA.
• 30 dBC.
• 35 dBZ.
• 40 dBF.
Environmental effects
The typical time interval needed to stabilize after changes in environmental
conditions is 5 minutes for each 10 C change.
Temperature
Operating
- Less than ±0.5dB effect over -10
o
C to 50
o
C (14
o
F to 122
o
F).
Storage
- 25
o
C to 70
o
C (-13
o
F to 158
o
F).