In this lesson we will look at some basic concepts for ear training, like reconizing different frequency ranges, comparing the characteristics of two similar sounds. We will also try to get a feel of the spatial properties of a sound, in terms of reverberation and spatial position. Finally, we will look into recoginition of timbre, using some classic waveforms as our starting examples. In this context we will also discuss how to describe timre, hinting at a vocabulary for talking about sound.