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| tips:recording_ultrasound [2023/08/29 13:01] – mrkva | tips:recording_ultrasound [2023/08/31 16:27] (current) – mrkva | ||
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| - | Ultrasound refers to sound waves with frequencies higher than the upper audible limit of human hearing. This means that we can't perceive them, but fortunately, | + | Ultrasound refers to sound waves with frequencies higher than the upper audible limit of human hearing. This means that we can't perceive them, but fortunately, |
| To get started, you'll need a recorder capable of recording at a sample rate of 96 kHz or 192 kHz. The latter is preferred. The theoretical limit you can capture with a 96 kHz sample rate is half of that – 48 kHz. With a 192 kHz sample rate, you can record sounds up to 96 kHz. Keep in mind that this is a theoretical limit based on [[https:// | To get started, you'll need a recorder capable of recording at a sample rate of 96 kHz or 192 kHz. The latter is preferred. The theoretical limit you can capture with a 96 kHz sample rate is half of that – 48 kHz. With a 192 kHz sample rate, you can record sounds up to 96 kHz. Keep in mind that this is a theoretical limit based on [[https:// | ||
| - | Secondly, you'll require microphones capable of capturing ultrasonic content. LOM Uši, mikroUši, and basicUcho series microphones are suitable for recording ultrasonic sounds, and we encourage you to test them for this purpose. In terms of performance (signal-to-noise ratio at higher frequencies), | + | Secondly, you'll require microphones capable of capturing ultrasonic content. LOM Uši, mikroUši, and basicUcho series microphones are suitable for recording ultrasonic sounds. In terms of performance (signal-to-noise ratio at higher frequencies), |
| For your first subject, you can use a very basic ultrasonic generator – keys. By shaking a set of keys, you can generate bursts of ultrasound reaching almost 80 kilohertz! However, don't let the audible part of the sound fool you; there' | For your first subject, you can use a very basic ultrasonic generator – keys. By shaking a set of keys, you can generate bursts of ultrasound reaching almost 80 kilohertz! However, don't let the audible part of the sound fool you; there' | ||
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| - When exporting from Audacity, I recommend changing the Project Sample Rate (in Audio Settings) from 192 kHz to a smaller value. There' | - When exporting from Audacity, I recommend changing the Project Sample Rate (in Audio Settings) from 192 kHz to a smaller value. There' | ||
| - | As a real world example, I recorded bats with mikroUcho type microphone. You can download the ultrasonic original [[https:// | + | < |
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| + | As a real world example, I recorded bats with LOM mikroUši series | ||
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| + | Following images illustrate the frequency shift. The spectrograms look practically identical, but notice the frequency range on the right side. Inaudible ultrasonic sounds are now in audible range. | ||
| - | Following images illustrate the frequency shift (notice the frequency range on the right side). | ||
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| + | ===== Interesting links ===== | ||
| + | * [[https:// | ||
| + | * [[https:// | ||
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