3M DL, SE Environmental effects

Appendix A
128
Models SE and DL
Octave filters (optional)
Number of bands ~ Eleven bands, with center frequencies (fc) 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 fc and 1.414 fc.
Octave skirts ~ With respect to fc:
• fc/2 frequencies - Approximately 20 dB down.
• 2fc frequencies - Approximately 30 dB down.
• fc/10 frequencies - Approximately 70 dB down.
• 10fc frequencies - Approximately 95 dB down.
Third-octave filters (optional)
Number of bands - Thirty-three bands, with center frequencies from 12.5 H z
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 fc and 1.12 fc.
Third-octave skirts ~ With respect to fc, the fc/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 0 59-703 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 t hese measurements,
the instrument was set to the lowest range and to a s low response time.
• 22 dBA.
• 30 dBC.
• 35 dBZ.
• 40 dBF.
Environmental effects
The typical time interval needed to stabilize after c hanges in environmental
conditions is 5 minutes for each 10 C change.
Temperature
Operating - Less than ±0.5dB effect over -10 oC to 50 oC (14 oF to 122 oF).
Storage - 25 oC to 70 oC (-13 oF to 158 oF).