To change the filter settings on your DUO, start by turning on the device by pressing and holding the action button for two seconds. You can then choose to quick record by clicking the button twice in succession. Note that the DUO needs to be connected with the Eko application to initiate a recording because no data is stored on the DUO. To change the filter settings, press the button three times quickly, in succession. This will allow you to switch between the four filter options.
As described in the quick start guide in the box, the four filter options are (see image below):
- Diaphragm (default) mode, 100-500Hz
- Bell mode, 20-200Hz
- Midrange mode, 50-500Hz
- Extended mode, 20-2000Hz
For more information on the DUO filters, go to 1:20 of this video: https://www.youtube.com/watch?v=p7IZF9PZeKc&t=6s
See the below image to see what all of the LED light states mean.