A very old idea for a high-fidelity speaker system deserves a new look.
There was an interesting article in the January 1961 issue of Popular Electronics, “Sweet Sixteen” by Jim Kyle. It was followed up in April 1961 with a second article entitled “Sweeter With A Tweeter.” You can find some discussion of the original article on the forum Audio Karma.
The basic idea was to create a hi-fi loudspeaker using an array of small speakers wired up to function as one entity. With each speaker handling only a small amount of power, using a composite of 16 interconnected speakers, all hooked up with the same phase of voltage versus direction of speaker cone deflection, the result was a speaker system with the ability to handle high power without distortion. Also, the cabinet in which the speakers were mounted could be made quite shallow, an advantage if one’s living room space was a little bit limited.
Some suggested wiring diagrams were provided, but one possibility was overlooked (Figure 1).
Figure 1 The 16 speakers could be interconnected so that their composite impedance at the two terminals would be the same as the impedances of the individual speakers themselves.
The 16 speakers arranged four-by-four could be interconnected so that their composite impedance at the two terminals would be the same as the impedances of the individual speakers themselves. For example, if each of the speakers presented 8 Ω of voice coil impedance, the composite of 16 speakers would present that same 8 Ω.
Also, I don’t see why “sweet 16” is an especially magic number for the basic idea, at least apart from the possible association with debutantes. I would think that one could make a three-by-three array or a five-by-five array and achieve much the same results.
The wiring diagram is shown in Figure 2.
Figure 2 One could make a three-by-three or five-by-five array and achieve much the same results.
In each case, the composite impedance would be the same as each speaker voice coil’s individual impedance.
As to the choice of names, meh!
This article was originally published on EDN.
John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE).