One of the most intriguing concepts in speaker design is the notion that people have to sit in a very limited sweet spot - a carefully triangulated arrangement of a center line between our ears and the point source in a pair of speakers. For many music and audio enthusiasts, there's no other way - and preferably in a carefully treated listening environment designed for musical enjoyment. But what the market once dubbed as "living room stereo" is something that the vast majority of people completely ignore. Why would you even have to sit still to listen to music?

In the never-ending journey to understand and translate people's lifestyles into their designs, for years, multiple brands played around with integrated concepts that could be freely positioned. Those included trying to generate an expansive stereo image from a single-source system - for which, in fact, the original tube radios, TVs, and even the first portable stereo music systems in the 1950s were actually the inspiration.

Because people live with music and sound, and don't necessarily want to sit still when listening to speakers (who "listens" to speakers?), the notion of omnidirectional radiating designs, or 360-degree sound was in many speaker designers' minds and is always a recurring thought for many product strategists and not necessarily acoustic engineers. One way or another, omnidirectional speakers stayed in the market, without ever being a wining concept.

In this classic speaker from Speaker Builder, the author proposes a complete speaker design project with a pyramid-shaped cabinet, which he adopted for its distinct advantages over box-type speaker cabinets. The fact that its nonparallel walls minimize standing-wave effects, and the slanted front improves the time adjustment of the drivers, added by the fact that the front is wide enough at the base to accommodate a larger woofer, and narrow at the top, where the tweeter is located, were the fundamental considerations. Also, the pyramid shape helps minimize diffraction effects and helps to improve sound dispersion, while the panel width also varies from bottom to top, which distributes panel resonances. "The only disadvantages of which I am aware are that a pyramid is more complicated to build and, for a given height and volume, it requires more floor space than, for example, a tower speaker," the author writes. This article was originally published in Speaker Builder magazine, March 1998.  Read the Full Article Now Available Here

Every month on Voice Coil's Acoustic Patents column, James Croft (Croft Acoustical) discusses different loudspeaker patents and inventions that are relevant to the audio industry. This article reviews a patent claimed by Polk Audio and granted in 2015, describing “a single-enclosure loudspeaker system that projects multichannel surround sound into a listener’s room, and so replaces multiple conventional surround channel loudspeakers.” The patent also describes, in one embodiment of the invention, that the “surround channel program material is pre-processed by an integrated wireless transmission device that performs certain digital signal processing and channel mixing steps in advance of wireless surround signal broadcast to a receiver.” This article was originally published in Voice Coil, January 2015.  Read the Full Article Now Available Here