If you are using your own audio samples, the license of the output should be the same as the input (samples). However, it doesn't look like this takes samples as input. The software itself appears to be LGPL 2.0, so it's possible the output would need to be licensed LGPL as well. I would say "contact the developers" but there is no contact information about this. If you're concerned about licensing, it may be best to stay away from this until you're able to get clarification from the devs.