The Brox Sisters, tuning a radio. Left to right, Patricia, Bobbe, Loryane. Radio broadcasting began in the US around 1920, and at the time of this picture radio listening was an exciting new high-tech pastime.  <a href="https://en.wikipedia.org/wiki/Vacuum_tube" class="extiw" title="en:Vacuum tube">Vacuum tube</a> <a href="https://en.wikipedia.org/wiki/radio_receiver" class="extiw" title="en:radio receiver">radio receivers</a> <i>(shown)</i> which became available about that time could drive <a href="https://en.wikipedia.org/wiki/loudspeaker" class="extiw" title="en:loudspeaker">loudspeakers</a>, allowing the whole family to listen together, unlike the previous <a href="https://en.wikipedia.org/wiki/crystal_radio" class="extiw" title="en:crystal radio">crystal radios</a> which required earphones so only one person could listen at a time.  Early receivers used <a href="https://en.wikipedia.org/wiki/horn_loudspeaker" class="extiw" title="en:horn loudspeaker">horn loudspeakers</a> <i>(shown)</i> to get adequate volume from the low gain early tubes.
Unnamed photographer for Bain News Service
Bain News service photo via Library of Congress site <a rel="nofollow" class="external autonumber" href="http://hdl.loc.gov/loc.pnp/ggbain.37038">[1]</a>