A normaliser is essentially the same as an audio compressor. What it tries to achieve is to make quieter sounds louder, and at the same time, any really loud sounds a bit quieter. This 'should' give you a more consistent audio level while playing instead of, for example, really quiet rocket sounds and then suddenly and immensely loud bang. The threshold is when it will start becoming active on a particular sound. Il have to check this, but i assume its working as a compressor threshold i.e. bigger value means quieter overall sounds. Although it could also be acting as a gain ratio... Il check this in a bit. The responsiveness is just that, how fast it will react to a change in sound, a smaller value should make it act less harshly with a larger setting making it only react for prolonged sounds or those with excessive energy. Just note, the two here are a rather crude way of normalisation. From an audio engineers perspective you would normally have many more variables so... I'm kinda guessing at which way the sliders work based on the assumption that responsiveness is done in ms (i.e. 16ms from your screenshot) and the normalisation as a compression ratio, as stated above. Hope this helps.