Sennheiser raised the stakes in the high-end, active-noise-reduction (ANR) headset game with the release of the S1 Digital at the EAA AirVenture show in Oshkosh, Wis. this week. Regular price for the S1 is $995 for the rest of this year, then $1,095. In August, Sennheiser will offer an optional XLR 3 power adapter and a 12-volt cigarette lighter adapter (including an extra female adapter) for the S1. The S1 Digital will run for 25 hours with Bluetooth on, using two lithium AA batteries, or 40 hours with Bluetooth off.
The S1 Digital includes built-in Bluetooth for wireless connection to mobile phones and music players. Music mutes automatically when communicating with ATC. BMW Group DesignworksUSA partnered with Sennheiser on the S1design.
The S1 Digital incorporates many new features that should appeal to pilots who are looking for that just-right headset. Chief among these is the S1’s adaptive ANR NoiseGard technology, activated by a “Smart Update” button on the outside of the left earcup. Each time the user pushes the button, the headset measures then adjusts to the existing noise environment, maximizing the noise cancelation. A pilot might, for example, push the Smart Update button during takeoff, then push it again after leveling off in cruise.
Sennheiser engineers placed two microphones on the outside of the earcups and two on the inside, which allows for optimum noise canceling in a variety of noise environments. Most ANR headsets use analog filters, according to engineer Heinrich Esser, and these filters are static, so they can be optimized for certain noise circumstances. With powerful digital-signal processors, noise-canceling can be adjusted using carefully designed algorithms. This has the added benefit of allowing the earcups to be larger to accommodate a larger variety of head and ear sizes. ANR-headset design is simpler with smaller earcups, he explained, but a digital system can handle the larger volume inside larger earcups. Gel earcups are optional.
Because the S1 Digital is designed for a greater variety of head sizes, it has to be more adjustable to fit comfortably on every head. Therefore, the headband has three earcup contact-pressure adjustments on each side, ranging from five to seven newtons. For older pilots with some high-frequency hearing loss, another control offers three steps of treble boost, which can help improve speech intelligibility. Finally, the headset is designed to provide the best possible noise attenuation in passive mode, with ANR off or if batteries are depleted.
“ANR can work only to a certain frequency,” Esser pointed out. “But there is noise beyond that.” The ear cushions also have provision for eyeglasses in the foam structure, allowing the foam to squish around eyeglasses to retain a noise-proof seal. “The target for us is the best performance for every user in every airplane,” he said.