dulcet
Concise Oxford English Dictionary © 2008 Oxford University Press:
dulcet /ˈdʌlsɪt/
▶adjective (of a sound) sweet and soothing.
– origin ME doucet, from OFr. doucet, dimin. of doux, from L. dulcis ‘sweet’.
'dulcet' also found in these Oxford entries:

