Technical Specifications

The ER-7C Series B probe microphone has an equalized flat frequency response from a small-diameter .95 mm O.D. probe tube. The equalization network is contained in an accompanying preamplifier and is individually adjusted for each microphone. A built-in acoustic calibrator provides a tone of 94 dB SPL at 1 kHz. The preamplifier is battery operated (9-volt alkaline battery) which prevents ground loop problems when the probe system is connected to other equipment. When the green test indicator does not illuminate during calibration operation, replace the battery.

Calibrator built into preamplifier: 94 dB SPL@ 1 kHz
Probe Tube: .95 mm OD x .58 mm ID x 76 mm long (approx. 3.0") medical grade silicone rubber
Sensitivity: 50 mV/Pascal (-46 dB re 1 V/u Bar): 0 dB SPL = 0 dB uV
Limits: ± 1 dB at 1 kHz; ± 2 dB between 250 and 10 kHz
Output Impedance: 235 Ohms, typical
Undistorted Output: 126 dB SPL (2 Volts) min., 5 mA min. in "0 dB" position
                                      (140 dB SPL min. in "-20 dB" position)
Noise Level: 55 dB SPL equivalent 20 Hz to 20 kHz bandwidth, typical
                        45 dB SPL equivalent 20 Hz to 5 kHz bandwidth, typical
Acoustic Polarity: Positive acoustic pressure gives positive voltage
Temperature: 0-50° C
Humidity: 0-95% relative humidity, non-condensing
Microphone Cable: Replaceable, 2 m (78") two-conductor miniature, with shield
Battery Life: Approx. 200 hours