Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
M:6/8
K:C
['g2 ^f a2 f gec cBc dBG', 'Bdg gfg']  
X:1
L:1/8
M:6/8
K:C
|: g2 ^f a2 f | gec cBc | dBG GAB | cd^d ef^f | g2 ^f a2 f | gec cBc | dBG GAB | ced c3 :: 
[K:G] Bdg gfg | Bdg gfg | fga agf | age d2 c | Bdg gfg | Bdg gfg | fga agf |1 g3 d2 c :|2 
 g3 ge=f :|  