Cacophonous: adjective - discordant sound; ill-sounding.
'Rehearsing the junior orchestra for the school play was always a trial for Tony; their inability to play either in tune or in time resulted in a cacophonous output that was enough to drive any music lover to drink.'
Harmonious: adjective - tuneful, sweet-sounding; sounding together in harmony.
'Blending the melodious voice of the soprano with the deep baritone singer provided a harmonious duet that proved a delight on the ears of all those who heard it.'
Pic: The deserted medieval village of Wharram Percy in East Yorkshire.