It is not going to do anything until you let go of the button, (or lower the phone if using tilt).
Hold the phone at least a few inches from your mouth.
Also check which mic source you have selected in VoxWav settings. Try with "VOICE_RECOGNITION" first. Adjust level in TcpMic settings if necessary, as Kalle suggests.
If that doesn't work well then try with "MIC", or other mic sources.
It is possible you just have a really crappy microphone on your phone, but most likely it is a settings or method of use problem.
On my tablet and on my wife's super cheap phone, I get virtually instant recognition when I let go of the speak button. Neither works well in a noisy environment though since they have no noise cancelling on them.