Patent Review: Compact Wideband Bass and Midrange Horn-Loaded Speaker System

This patent describes, a compact high-fidelity sound reproduction system achieving high efficiency, low distortion, wide bandwidth, and extended low-frequency reach, and which can be used as a sub-bass woofer, bass woofer, mid-bass woofer, and mid-range speaker for residential or commercial large venue applications. The system includes a dynamic driver driven bass horn, a looped resonator duct (ring geometry), which can be folded, and an adjustable feedback duct allowing sound characteristics to be tailored. This article was originally published in Voice Coil, April 2016.

This review discusses an invention that promises to successfully process an audio signal to focus an acoustic signal by an arrangement of a plurality of loudspeakers, using a frequency analyzer, a signal processor, and a signal output interface. The frequency analyzer is configured to determine a fundamental frequency and the signal processor configured to adapt an overtone of the fundamental frequency. An approach that can work quite well, even though there are well-known drawbacks that the patent intends to resolve.

In this edition of Test Bench, we characterize the SB42FHCL75-6, a 15” home audio subwoofer from OEM driver manufacturer SB Acoustics. The SB42FHCL75-6 has an impressive feature set, with a stiff 15” cone, NBR high-excursion surround, and 6.5” diameter flat cloth spider, driven by a 3” four layer voice coil. The motor system utilizes two stacked 20-mm thick ferrite magnets sandwiched between a polished 8-mm thick front plate. This article was originally published in Voice Coil, April 2016.

This month, I received a ribbon transducer for Test Bench analysis from Tang Band (TB) Speaker. The RT-2202S device is a closed-back ribbon tweeter with a fairly small 30 mm × 10 mm ribbon diaphragm. Features include a thin aluminum foil diaphragm, an injection-molded face plate, a metal chassis, Nd-Fe-B (neodymium) magnet, and a matching transformer. This article was originally published in Voice Coil, April 2016.

Three great amplifier designs, practical test and measurement, acoustical treatment advice, and more are all included in audioXpress April 2016. Building new audio products with audio networking? Then don’t miss this month’s Standards Review article on RAVENNA/AES67 development.