In the very
early years of radio, headphones was about all there was for
sound reproduction. The horn speaker became the norm in
the late teens. Most early horn speakers consisted of a sound magnifying horn with a what was not much more than the sound element of a headphone attached to the base.
When you purchased your new radio in the early 1920's most of
them did not have enough power to drive a loudspeaker so
headphones was how you listened. Many companies offered one or
two stage (some had three) audio amplifiers that would
amplify the weak audio sound enough to drive a loud speaker.
Early amplifiers and loudspeakers of any brand of could be attached to the simplest of radio receivers (even crystal sets) so the whole family could listen.
Loud speakers were usually an option and if desired were purchased separately. Most all permanent magnet speakers of the 1920's had an impedance of around 2000 ohms
(DC resistance; typically 1500 - 2000 ohms). All permanent magnet (2 wire type) speakers were compatible with any radio of that era that could drive a loudspeaker. This applies to both the horn and disc type speakers. The disc (or cone speaker) were introduced in the mid late 1920's and were compatible (and proper for use) with any brand 1920's radio. This applies to either battery or the early AC sets. The exception was some of the AC operated sets made in the late '20's required an
electrodynamic speaker (more on this type later).
I should mention that there were certain speakers that were promoted but not included with the purchase of a particular Radio, for example; the
Radiola 44 and
60 were both promoted with the
Radiola 103 speaker, these are shown on the "Radiola Info" page. The
Radiola Super-Heterodyne portable and the
Radiola IIIA were sold with the
It was quite common to have a radio
with a speaker brand of another company as many speaker companies did not make radios and some radio companies did not make speakers. It is proper and ok to use any radio - speaker combination of that era as few sets came with a speaker unless it had one built-in or a combo pack was offered. There were a few (very few) speakers designed (cosmetically) to go with a particular radio, an example was the RCA
Radiola 33 receiver that was sold with the
Radiola 100B speaker.
Speakers with only 2 wires are permanent magnet (PM) type. Speakers with 3-4 or more wires
are "electro-Dynamic) and designed electrically for a particular
radio or amplifier. They will have a special plug that plugs into the radio chassis
or hard-wire in. These type speakers were not usually compatible with other radios. You should never apply power
to a radio with a proprietary speaker (electric sets) without the speaker connected. Doing so will almost always result in damage to the radio's power supply.
These 3-4 wire speakers are "electro-dynamic", that is
their magnet is energized by a coil (field coil) which is part of the power supply circuitry of the radio
and becomes a magnet when powered. A good example of this type is the
Atwater Kent 55.
I am often ask if these early speakers can be operated from a modern radio or amplifier, that answer will be found on my