March 13, 1923: On this day the new improvement of radio receiver was advertised: listening to the radio without headphones! The improvement was on speaker that could eliminated the need for headphones. Headphones were less liked because it heavy and may undermine a good hairdo. The new radio receiver model known has a 'foolproof' design.
After several years the radio called superhet became a best selling product. In the early 1920s the superhet doesn't needed because there was only a few radio stations that run at the time. But after 1920, number of radio station and old time radio shows grew so fast, following that, need of selectable or fine tuning radio receiver became more apparent. Since that many developments has done to improve the radio receiver performance.