At the cusp of the ultra-thin TV and soundbar market explosion, a long-standing Warkwyn Associates client decided to develop very shallow on-wall loudspeakers to complement the new shallow flat panel TVs.
We started the project by bringing in many current small transducer samples available at the time. We measured and analyzed the transducers acoustically and mechanically in order to establish performance benchmarks.
We theorized that if the cone was inverted we could significantly reduce the vertical height (driver depth). In typical inverted dome transducers the voice coil is positioned at the periphery of the dome. As these transducers are not usually expected to perform below 1kHz the excursion is very short, making a secondary suspension (spider) a negligible concern. The client wanted the driver to play as low in frequency as possible, so the new transducers needed longer excursion, and for that we needed to find a way to insert a spider. We developed a hybrid dome driver with increased height and the excursion capability of conventional transducers.
We built several prototype versions of the inverted cone transducer with various dome shapes and thickness. Our measurements of these early prototypes proved promising. The final design ~ 4″ diameter transducer had a sensitivity of 85dB SPL and bass extension below 120Hz.
The last issue to resolve with this new transducer was to figure out how to get mass production to position and size the tinsel leads to have long enough excursion without hitting other parts and creating buzzes. Because of the inverted cone, there is very little room for error in tinsel lead routing as compared to conventional transducers.
We worked closely with the offshore contract manufacturer over several months to iterate various designs to resolve the tinsel lead issue. Working with manufacturers, understanding their strengths and being forthright with them creates an atmosphere of mutual respect and cooperation.
For this unique design, a US patent was granted:
US 8638968B2- XTR