Yes, LOUDSPEAKER is a Scrabble word!

Letter values in Scrabble US: L 1, O 1, U 1, D 2, S 1, P 3, E 1, A 1, K 5, E 1, R 1.

Is it a valid word?

LOUDSPEAKER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance

Also: speaker unit, loudspeaker system, speaker system.