After talking a little about how horns, I closed Installment #2 of this continuing series by saying that the advent of the stereo LP in 1957 had brought with it "...a whole new set of parameters ... that drove - at least temporarily - the nails into the coffin of most of the speakers then available, including the horns."
That was true, of course, but the thing that did-in those earlier speaker designs wasn't really the stereo LP, but the growth of stereo, itself. Even as early as 1957, when the first stereo records came out, stereo recording and playback had already been around for a good long time. Bell Labs had been experimenting with it for decades, and the sound track for the Disney film, Fantasia (1936), had been recorded in six- channel (!) optical stereo. What eventually made stereo recording more than just a curiosity, though, and brought with it the obsolescence of most then-current speaker designs, began with the development, after World War II, of captured German "Magnetophon" tape recorders into EDITABLE high-quality sound recording and playback devices.
Yup; it wasn't the sound quality that ultimately gave the tape recorder dominance of the recording industry, but the fact that, unlike discs (or the earlier cylinders) which couldn't be edited at all, or optical recording which possibly COULD be edited, but only with the greatest difficulty, or even the wire recorder, which could be edited by just cutting the recording wire and then tying a knot in it to make the necessary new splice, tape recording (especially after the invention of the EdiTall block) was actually easy; able to make perfect edits; and, at the hands of a skillful editor (and unlike the wire recorder), completely free of pops or skips. That made for HUGE potential increases in recording industry productivity and corresponding cost reductions for all kinds of recording - whether soundtrack, music, radio transcription, or even (later) data -- and guaranteed that whatever innovation would be done in recording would be done first in the tape medium.
With tape recording to make it both possible and easy, the first big innovation was in sound-on-sound recording, which was followed by first two, and then multi-channel stereo. And tape was so successful and so well received in the professional-, and then the audiophile-community, that by the early mid-1950s commercial two-channel pre-recorded stereo tapes (initially using "staggered" and, later standardizing on "stacked" playback heads) were offered for sale. I remember hearing (and lusting after) such tapes played on a Berlant Concertone tape recorder at Valley Electronics Supply Company, probably sometime around 1955, but of course, being a kid, I had no money for such things and could only wait and hope for "someday" when things would be different.
By the time I could afford my first stereo playback "tape deck" (made by "Viking of Minneapolis"), stereo records had come out and I bought my first stereo phono cartridge - an Electro-Voice ceramic unit which was the very first stereo cartridge available to the public - at about the same time.
What both of those purchases (along with the second amplifier and speaker that we needed in order to use them) brought to me and to all of the other people so eagerly buying the new phenomenon was just two things: "right" and "left". What we now think of as "imaging" was, at that time, only the ability to follow the bouncing ping-pong ball or the locomotive or the marching band or the jet fighter plane or whatever else it might have been, as it traversed our listening room, moving one way or the other. There was no perception at all of front-to-back depth and none of what we now call "soundstaging", and, never having experienced either of those things, we didn't know that they were missing.
We found-out about them, though, soon enough: Once the stereo record came along to make what had, for most people, been just a movie-theater-only novelty into a generally-available at-home experience, people wanted it and were willing to spend money to buy it. That resulted in strong competition among manufacturers and dealers to seize what seemed to be an almost limitless market and, particularly in the area of loudspeakers, it resulted in a whole new understanding of what they do; how they do it; and in a whole new wave of innovation to allow them to do it better.
For stereo, even if people already had a "hi-fi", if it was "mono", they still had to buy another speaker in order to get the other stereo channel. Manufacturers were quick to pick up on this and set out to find reasons to make them want to buy both speakers of the stereo pair instead of just one. The answer came from the nature of stereo, itself: For a monophonic recording, all of the music comes from a single speaker system and, other than keeping the system's various drivers (assuming that it has at least two -- a woofer and a tweeter) relatively close together, how the drivers are arranged relative to each other or where the system is placed in the listening room makes little difference.
For stereo, it's entirely different: The music is made by both the right and left speakers working together and, to get the music to "image" properly (show the size and placement - both right-to-left and front-to-back - of the performers or instruments) and to "soundstage" (show the size and shape of the room the performers are playing in) properly, the positioning of the drivers relative to each other and of each of the two speakers of the stereo pair to the other and to the listener is crucial. This is because stereo's directional and distance information is the result of differences in phase and arrival time and the positioning of the drivers, the speakers, and the listener will affect both of those things directly and make a huge difference in how a stereo system sounds.
Because of this, the first thing that speaker manufacturers recommended to new stereo customers was that both speakers - whatever they were - should be identical. Most people thought that that was just to ensure identical frequency response for the two stereo channels, but in fact, it had just as much to do with phase relationships and arrival times.
Beyond that, manufacturers and knowledgeable dealers started producing and recommending new brands or models of speakers designed and intended specifically for stereo sound reproduction.
I'll write about those and more about why they were needed and why most existing speakers - especially horns -- couldn't work in my next article.
See you then!