What is meant by an isolation booth?

          An isolation booth is a standard room in a recording studio. Typically, it is soundproofed to keep out external sounds, and keep in the internal sounds. It is also designed in such a way as to have lesser amount of diffused reflections from walls, in order to make a good sounding room. 

          In a professional recording studio, there may be one or more small isolation booths, along with a control room and a large live room. All of them are usually soundproofed with double-layer walls and insulation in-between the two walls.

          The first soundproof booth is said to have been invented in 1876 by Thomas A. Watson. He developed it to be used for demonstrating the telephone with Alexander Graham Bell. However, he did not patent it.

          Today, there are variations of the same concept, like a portable standalone isolation booth, and a compact guitar speaker isolation cabinet.