An electronic music speaker, amplifier or sound system.

Speaker

Half Body person with a raised hand talking, a teacher explaining or a man making a presentation.

Half Body Person With Raised Hand

A person sitting down, with his computer and headphones, participating in an online class, watching a movie or listening to music.

A round retro vinyl or a CD with a hole in the middle to play music. 

A round bubble with a teacher or presenter inside, giving a class and pointing a board.

A busy and overworked manager or employee surrounded by charts, graphs, and notifications.