Band playing the tango for most of next month (6)
I believe the answer is:
septet
'band' is the definition.
(I know that Septet is a type of band)
'playing the tango for most of next month' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'tango' could be 't' (phonetic alphabet: alpha, bravo, charlie etc.) and 't' is found within the answer.
'month' could be 'sep' (abbreviation for September) and 'sep' is found within the answer.
A single letter 'e' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for septet that I've seen before include "A set of seven" , "Several players" , "Group of seven voices" , "Work for seven players" , "G7" .)