Old evil upset speakers — they may go into further detail (11)

'they may go into further detail' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'old evil upset speakers' is the wordplay.
'old evil' becomes 'bale' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'upset' says the letters should be written in reverse.
'speakers' becomes 'orators' (orator is a kind of speaker).
'bale' backwards is 'elab'.
'elab'+'orators'='ELABORATORS'

Can you help me to learn more?