FS-5568 --resolve the real problem is that L=-1 is not valid because the L param is about how many times to generate the output while generating the tone so -1 is impossible because it can never end to let you hear it.  The real fix is to not allow -1 loops=-1 is the correct way to do this because that is parsed after the tone is generated and repeats the entire thing.  Doing something like L=100 actually generates the whole slinear audio 100 times into memore where loops=100 only generates the little snippet and repeats it after it was generated.