Knowledge Base

Solution

1. First, try to know what amplitude is the noise signal. Draw a rectangle around the horizontal line, without including any call.
2. A call definition is defined. Look at the spectrogram that appears at the bottom-right corner. Hover the mouse over the horizontal line and get a feel of the amplitude of that signal. Take note of the maximum values you see.
3. Select the call definition and click the Remove button.
4. Draw a rectangle around a call.
5. Select the new call definition and click the Edit button. Set the Min-Amplitude parameter to a value well above the values of the noise.
6. Click Detect the calls in this recording.

Problem

After clicking Detect the calls in this recording in the Call Detection screen, processing goes very slowly.

Solution

Right-click the spectrogram area and reduce the Overlap, for example to 50% or lower.

See Also

• Spectrogram Settings
• Overlap

Problem

When examining the Call Statistics table, the value of Duration is not the same as one would obtain by calculating the difference between Stop Time and Start Time.

Solution

The value of Duration is obtained with the difference between Stop Time and Start Time using six decimals, that is, more than those you see in the table (three for both Start Time and Stop Time). After that, the value is rounded to the milliseconds. This is the reason why you see a discrepancy between Duration and the value expected from Start Time and Stop Time in the table. The result is, however, very accurate.

Source: UltraVox XT 4 - Calls, Noldus Information Technology