Why were early sound-film cameras placed inside soundproof booths called iceboxes?

During the early transition to sound in cinema, cameras were placed inside soundproof, glass-paneled booths to prevent microphones from picking up the noisy whir of the motorized cameras. Because these microphones were omnidirectional and had a limited range, they were highly sensitive to ambient set noise, including the mechanical operation of the cameras.12

These booths were facetiously nicknamed "iceboxes" because they were uncomfortably hot and stuffy for the operators trapped inside. This confinement severely limited camera movement, as the equipment could only pan slightly on its tripod, contributing to the static nature of many early sound films. By 1931, studios began replacing these booths with lightweight, soundproof camera housings known as "blimps," which eventually led to the development of quieter, self-insulating cameras that eliminated the need for external soundproofing.12