anchor: Source:getAttenuationDistances
  Gets the reference and maximum attenuation distances of the Source. The values, combined with the current DistanceModel, affect how the Source's volume attenuates based on distance from the listener.
  ref, max = Source:getAttenuationDistances()
  ref number The current reference attenuation distance. If the current DistanceModel is clamped, this is the minimum distance before the Source is no longer attenuated.
  max number The current maximum attenuation distance.