Tuneful
/ˈtuːnfl/
Definition 1 of 1
Pro Tip 1/3Positive Vibe
Tuneful often implies something cheerful and pleasing to listen to. 
The birds chirped a tuneful melody that brightened my morning.
Pro Tip 2/3Musical Quality
'Tuneful' suggests a high musical quality, like a well-rehearsed performance. 
The choir's rendition of the hymn was exceptionally tuneful.
Pro Tip 3/3Catchy Sound
A tuneful song is often catchy and easy to remember because of its melody. 
His new single is so tuneful, I can't stop humming it.