Head cheese initially joined heavy-metal turnout (7)
I believe the answer is:
cranium
'head' is the definition.
(I've seen this before)
'cheese initially joined heavy-metal turnout' is the wordplay.
I cannot really see how this works, but
'metal' could be 'ra' (Ra is an example) and 'ra' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for cranium that I've seen before include "Skull, bones enclosing brain" , "Brainpan" , "Skull of a vertebrate" , "Brain container" , "Brainbox" .)