<<Is there any point in using a higher sample rate if the mics we use
only go up to 20 kHz? We would not be able to capture animal sounds
above 20 kHz no matter what the settings on the recorder.>>
When a manufacturer states that the response of a mic is, say, 40Hz to
18kHz, they mean that amplitudes within this range will be portrayed
with approximately equal output, usually + or - 3db. Sounds outside
that frequency range don't disappear, they merely are at a lower
volume, falling off usually in a bit of a ramp to a frequency perhaps
as much as an octave higher where the microphone has a sensitivity
that is basically null. The manufacturers concentrate on the audio
quality within the stated range & let frequencies outside that range
fall where they may, & often this higher & lower frequency response is
quite ragged as the sensitivity drops off past the point stated.
Stated frequency response for a given microphone is generally its
least important attribute, except in the rare case of microphones
intended specifically for extended bandwidth purposes.
Scott Fraser
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