3.The loudspeaker's stopped working.
4.a portable loudspeaker with built-in microphone and amplifier.
5.a loudspeaker that reproduces higher audio frequency sounds.
6.a loudspeaker that reproduces lower audio frequency sounds.
7.I bought an amplifier yesterday.
8.The electronic amplifiers made music more penetrating.
9.The conference hall was installed with radio sets and megaphones.
10.Loudspeakers belched out deafening pop music.