There was once a time when any credible mixing studio would not be seen without a pair of Yamaha NS-10 monitors. They are the black speakers with the white cones and are well recognized even by lay persons, in fact many people still swear by using them today. However another very common but less well known loudspeaker was the Auratone 5C. This speaker was very unassuming, a 5 inch single circular driver in a small wooden box. The goal of this speaker was to allow an audio engineer to have a focus on the critical mid range frequencies of an audio mix.
Almost all instruments and voices have mid range components and it is a frequency range which can easily get cluttered and such a speaker as the Auratone 5C allowed the engineer to reference the mid range without the ambiguities of multi driver loudspeakers. This type of speaker also approximated the reproduction characteristics of television sets, small radio receivers and other small devices from which sound would be reproduced.