3M DL Environmental effects, Octave filters optional, Third-octave filters optional, Temperature

128Appendix A

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 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 fc and 1.12 fc.

Third-octave skirts ~ With respect to fc, the fc/2 and 2fc 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 oC to 50 oC (14 oF to 122 oF). Storage - 25 oC to 70 oC (-13 oF to 158 oF).

Models SE and DL