Innovations in Headphones and Speaker Drivers in Voice Coil June 2016, Now Available!

May 23 2016, 03:00
Learn how to design really innovative earphones and headphones using the latest technologies with the June 2016 issue of Voice Coil. Also included is a complete directory of key Earphone and Headphone suppliers, our regular column on Acoustic Patents and characterization of the recently released 6.5” midrange Scan-Speak 18M/4631T00 Revelator. Now Available!
The June 2016 issue features a Spotlight article on “Innovations in Headphones,” by Mike Klasco (Menlo Scientific). As this renowned headphone-design expert comments, there’s increasing pressure on engineering teams to bring new products to market and unfortunately too many “off-the-shelf ODM designs” lacking in audio quality, features, functions, and comfort. For those companies and designers looking at introducing products in a crowded marketplace, the article details a series of trends and innovations that could contribute to a more compelling offering. The article details innovations in materials that could contribute to increased comfort and new bio-fiber composites, which potentially could result in lighter and better-looking housing and enclosure designs, as an alternative to plastic or metal. Klasco also details new electronic components that can support superior split-ground topologies and offer integrated solutions with DAC and amplifier combined, new nano-coating solutions for circuit board treatment, allowing splash-proof designs and better moisture and heat protection, and even biosensor modules and new equalization algorithms allowing superior earphone and headphone calibration and personalization. 
Complementing this essential reading, Voice Coil features a complete directory of key Earphone and Headphone suppliers, compiled by Nora Wong. Get the updated contacts for companies doing original equipment manufacturer (OEM) or original design manufacturer (ODM) work in this field.
Voice Coil offers a contribution from Zarina Bhimaniom (Listen, Inc.), explaining how, a company from Cambridge, MA, part of the USA Today network, carries out quantitative reviews on a wide range of consumer electronics products, using standardized scientific testing procedures to examine its performance, combined with a proprietary scoring method to ensure a level playing field among all manufacturers. The article discusses’s headphone test methods, which uses a recently upgraded Listen SoundCheck system.
In his monthly column on Acoustic Patents, James Croft (Croft Acoustical) discusses a new and intriguing speaker design patented by Walter Ka Wai Chu, from Taiwan, which was recently granted. The invention describes a speaker device that includes a main cabinet and a speaker mounted on the cabinet body, complemented by an extendable cabinet composed of a bellows tube and a passive diaphragm, the bellows tube having a front end connected to the cabinet body and a rear end closed by the passive diaphragm, and the passive diaphragm being axially aligned with the speaker. The design also includes a damping assembly being arranged in the cabinet body and in the bellows tube, and having a front end connected to the cabinet body and a rear end to the passive diaphragm. With these arrangements, the speaker device can potential improve the bass performance in the entire low-frequency band instead of being limited to only a few low-frequency points, the inventor claims. While Croft confesses to being somewhat skeptical of whether, in its current disclosed form, the device will provide a useful advantage, he found the design sufficiently interesting to be analyzed in more detail.
For this month’s Test Bench, Vance Dickason looks at a recently released 6.5” midrange driver from Scan-Speak. The new Scan-Speak 6.5” 18M/4631T00 Revelator is nominally a midrange version of the Scan-Speak 18W/8531G00 with higher sensitivity and shorter XMAX. The Revelator midranges are well known for their sliced paper cone technology. The slices are filled with damping glue, which dramatically reduces break-up modes in the diaphragm. In combination with Scan-Speak’s low-loss linear suspension and the patented Symmetrical Drive (SD-1) it represented a breakthrough in midrange clarity and overall smooth frequency response characteristics.
As Vance explains, the original Scan-Speak 18W/8531G00 was a true high-end audio classic and probably one of the most visible high-end drivers ever used in high-end loudspeakers, and the feature set for the 18M/4631T00 is very similar to the original 18W’s. This includes the updated slim profile cast-aluminum frame, a version of the original uncoated sliced paper cone, a 1.5” diameter sliced convex paper dust cap, 38 mm diameter voice coil wound on a titanium former, SD-1 patented Symmetric Drive (SD) motor structure with a 110 mm × 18 mm ceramic ferrite magnet. The Symmetric Drive motor uses an extended vented pole with an angled chamfer on the pole top section and three copper shorting rings, one centered on the gap and one located above and one located below the cap area.
The Scan-Speak 18M/4631T00 also has a T-yoke with a 12-mm diameter pole vent. Compliance is provided by a low damping styrene butadiene rubber (SBR) surround and a 3.5” diameter flat cloth spider. Last, the voice coil is terminated to a pair of solderable gold-plated terminals.
Don’t miss the full characterization of this driver. Download now the June 2016 issue.
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