Phone enquiries please call Australia: (02) 8005 5343 / International +61 2 8005 5343
The lowest frequency the Song Meter SM4BAT FS can record depends on two factors:
The 16k High Filter setting enables a high-pass filter (HPF) with a cutoff frequency of 16 kHz. The SMM-U2 and SMM-U1 microphones also have permanent high-pass filters with cutoff frequencies lower than 16 kHz. For all practical purposes, only the active HPF with the highest cutoff frequency matters.
An HPF is a filter designed to remove incoming signals below its cutoff frequency. In the case of the Song Meter SM4BAT FS, the purpose of the HPF is to prevent low-frequency sounds like wind or non-bat animal vocalizations from distorting your recordings or excessively triggering the recorder.
If you enable the 16k High Filter, sound lower in frequency than 16 kHz will be significantly reduced in volume. If you disable the 16k High Filter setting, then the microphone's filter will be the deciding factor:
Most filters take effect gradually as frequency changes. In the case of the Song Meter SM4BAT FS and its microphones, for each factor of 2 below the cutoff frequency, sound at that frequency is reduced in volume by 12 dB compared to sound above the cutoff frequency. For example, when using the 16 kHz HPF, sound at 8 kHz is reduced by 12 dB, and sound at 4 kHz is reduced by 24 dB.
The filters built into each microphone is sufficient to remove wind noise in typical environments. However, if you know that you do not need to record sound lower in frequency than 16 kHz, enabling the 16k High Filter will help avoid recording higher-frequency sounds such as insect drones and rustling leaves.
In the spirit of reconciliation, Faunatech acknowledges the Traditional Custodians of Country throughout Australia and their connections to land, sea and community. We pay our respect to Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander peoples today.
Faunatech
6/269 Victoria Road
Rydalmere NSW 2116
Australia
Australia: (02) 8005 5343
International: +61 2 8005 5343