Saturday, January 20, 2007
Early days of loudspeaker audio
The horn arrangement is a familiar one, taken from nature and also from the shape and construction of various wind instruments, like the tuba. Edison used a conical horn for his very first cylinder phonographs, followed later by more esthetically pleasing morning glory shaped horns and finally internally fitted horns placed inside the gramaphone cabinet. The external horn got its reprieve in the late teens and early twenties when radio first started making its way to the well-to-do and to experimenters. Manufacturers fitted bell shaped horns to simple electromagnetic reproducers that were little more than large headphone elements in order to produce loudspeaker volumes.
The radio shown here is a battery operated tuned RF type nicely enclosed in a sloping front cabinet. The excellent lighting and photographic composition, and the appearance of the gent in the photo suggest that this is a well posed shot of someone of note - perhaps a radio pioneer - enjoying the fruits of his labor. Please comment if you know who this is.
The horn is a directional impedance matching device which can greatly improve the efficiency of a small driving membrane, but it has its limitations. Today any audio through a horn like this is considered to be "telephonic" or worse, and it has been difficult to produce horn like loudspeaker systems with adequate bandwidth in the past, though the horn is still very much a part of the auditorium and public address technology mix used today, and is still being improved.
I think he needs a sub.