I need to detect two sounds (913 Hz and 1370 Hz), knowing the time in which each starts and ends.
At this time, I am using a band pass filter (butter), and this is the result:
Here is the first time this sound occurs:
The red line is where the sound is supposed to end (276 ms).
So how can I detect that the first time the tone occurs it starts at 0 ms and ends at 276 ms?