Audacity Forum

Hi,

I am new in Audacity.
I have speech signal. I need create constant value signal of let's say 0.05 sec that is unheard in normal play but to be detectable by Nyquist prompt. I tried square generator and cut from the file but it doesn't work. I can't detect inserted signal using Nyquist i.e. value of the signal is to low to catch it as different from silence (0).
Please help.

Regards

Pawel

You could generate a very high frequency sine wave at a fairly low level.
"Generate > Tone"

If you're using a sample rate of 44100 or 48000 Hz, try generating a tone at around 18000 Hz amplitude 0.05. That will be virtually inaudible unless you have exceptional hearing or your audio playback system produces sub-harmonics (not likely but possible). You can then detect those sounds by filtering out frequencies below about 17000 Hz, then use "Sound Finder", "Silence Finder" (or write your own modified version) to set labels where the sounds occur.