A free-field microphone is designed to measure the sound pressure in a sound field and compensate for the influence of it's presence in the sound field.
A free-field microphone measures the sound pressure as it existed before the microphone was introduced into the sound field; in effect, maintaining free-field conditions.
A free-field microphone should be pointed towards the sound source, i.e. at an angle of 0º incidence to the source.
| Type | 40BF | 40AM | 40AC | 40AE | 40AF | 40AN | 40BE | 40AZ | ||||||||
| Size | ¼" | ½" | ½" | ½" | ½" | ½" | ¼" | ½" | ||||||||
| Sensitivity [mV/Pa] | 4 | 12.5 | 12.5 | 50 | 50 | 50 | 4 | 50 | ||||||||
| Dynamic range [dB] | 40-174 | 27-160 | 27-160 | 15-146 | 15-146 | 15-146 | 30-166 | 15-146 | ||||||||
| Frequency range [Hz] | 10-100k | 3.15-40k | 3.15-40k | 3.15-20k | 3.15-20k | 1-20k | 4-100k | 0,5-20k | ||||||||
| Polarisation [V] | 200 | 0 | 200 | 0 | 200 | 200 | 0 | 0 | ||||||||
| Outside diameter [mm] | 7 | 13.2 | 13.2 | 13.2 | 13.2 | 13.2 | 7 | 13.2 | ||||||||
| Length [mm] | 10.5 | 12.5 | 12.5 | 16.2 | 16.2 | 16.2 | 10.5 | 16.2 |