What instruments are used for the harmony in a pop song and rhythm?

Answer 1

Generally speaking, any of the orchestral instruments are capable of providing harmony (excluding untuned percussion)! The composer might call for virtually any instrument to do that. But traditionally this role is taken up by the instruments of the lower registers such as basses, bassoons and tubas. It also would be very common for cellos, violas, clarinets, trombones and horns to take up that role.

Answer 2

An ensemble is merely a term for a group of instruments playing the same music. Any combination can be considered an ensemble: a string quartet, woodwind quintet, a brass choir, jazz band or a group of percussionists, for example. Even vocalist can be members of an ensemble of instruments or other vocalists.

Answer 3

There are many different instruments that could provide the harmony in a modern pop song. Everything from simple vocal harmonization, like the Everly Brothers or Simon and Garfunkel, to a string quartet, or even a full orchestra.

But modern pop songs usually rely on either Guitars or a keyboard to maintain that harmony.

As for rhythm, a bass player and drummer are essential, but a band may also have a percussionist. This is someone who provides additional rhythm by playing any of several different percussion intruments; like conga drums, or timbales. They may also have other instruments like a cowbell, slapstick, wood blocks, tamborine, etc.