Now let's break this down. First, the SoundType specifies the sound that will be played. Next, we have a Vector3d position. This position can be constructed, or it can be retrieved from a Location using the Location#getPosition() method. In the example above, the sound will be played at the coordinates 1, 65, 1. Lastly, we have the volume that the sound will be played at. The volume is a double that ranges from zero to two.
If a SoundCategory isn't specified when playing a sound, SoundCategories#MASTER will be used.