Principles I lowered for singers (5)

I believe the answer is:

bassi

'lowered for singers' is the definition.
'bassi' can be an answer for 'singers' (plural of 'basso', 'bass' in Italian). I am not sure about the 'lowered for' bit.

'principles i' is the wordplay.
'principles' becomes 'bass' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'bass'+'i'='BASSI'

(Another definition for bassi that I've seen is " Singers in opera".)

I've seen this clue in The Times.

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