Hi, I set an AM recording using a band-pass filter (see config file below) 0.9 - 3.4 khz, with a 5% amplitude trigger (I hoped this would mean that it would record events above a 5% threshold within the 0.9 - 3.4 range. However, the files produced are from 0 - 8 khz as if no band-pass filter was set, and it appears to be triggering on audio events at any frequency (up to 8khz). Anyone know what's gone wrong?
Thanks,
David
That sounds like a brilliant tool, will look forward to using it and thanks for the useful reply Alex.
Hi David, The band-pass filter is a 1st order Butterworth filter so it will reduce the amplitude of signals outside of the frequency band but not completely remove them. You'll still see signals over the whole 0 - 8kHz frequency range but they will be significantly attenuated as you get closer to 0 and 8kHz. The amplitude threshold is then applied to the post-filter signal. If you triggering on background noise then increasing the amplitude threshold will generally reduce the amount of data that is actually collected. We're currently developing a web app that will allow you to upload unfiltered recordings and then play with the filter and amplitude threshold settings to see their effect. This should make using this feature much more straightforward. We're hoping this will be ready for trial in a month or so. Alex