Plane & Pilot
Tuesday, July 12, 2011

Sennheiser S-1

With the introduction of the new S-1 and its adaptive, four-microphone sampling technology, Sennheiser sets a new headset standard

The S-1 enhances that idea by making the attenuation cover much more of the sound spectrum. It adds two more high-sensitivity microphones—this time mounted on the outside of the ear cups. These microphones pick up high-frequency noise from the airflow over the fuselage and from the propeller and engine. Combined, the four microphones block a wide swath of harmful frequencies. With a few exceptions, headsets use only one technique or the other. A quick glance at the attenuation curve for this headset reveals attenuation across many frequencies, not the usual, diagonal (and narrow) line of noise suppression common to typical ANR headsets.

The S-1 introduces Sennheiser's NoiseGard Digital, taking the technology even further. This system offers true "adaptive" noise reduction. By pushing a little button on the side of the ear cup at any point in the flight, the headset takes an audio snapshot of the sound environment at that very second. It samples the noise and creates an "anti-noise," but in real time. It's a sort of "parametric EQ" in reverse. Your headset can thus be continuously optimized throughout the flight! Other manufacturers who offer "adaptive ANR" do it by matching the offending noise to a preset approximation, not a true analysis. The difference in sound is significant.

Sennheiser brings a truckload of other useful enhancements to the S-1 to make it even more innovative. Research replaced gel ear seals (and their characteristic "hot spots") with special viscous foam, similar to the memory foam in high-end mattresses. It's light and airy yet creates a very tight seal. They engineered different areas around the ear seal, allowing for special soft spots where the temples of your glasses meet the seal, and a V-shaped elongation where your ear lobes go to eliminate rubbing. The S-1 sports adjustable clamping pressure for each ear cup—unique to Sennheiser. The ear cups are quite large and stand well away from your ear, making the S-1 uber comfortable.

To illustrate Sennheiser's attention to real-world environments, they provide a three-stage treble boost in each ear cup. As pilots age and their higher-frequency sensitivity decreases, they can boost the treble spectrum on each side independently. It's a thoughtful—and useful—addition. The headphones have a frequency response of 20 to 16,000 Hz, and feature peak-level protection to guard against volume peaks above 110 dB—considered the danger range. To bring out the best from different audio sources, the S-1 has two separate audio mixers: one for music, and the other for cell phone and ATC communications.

An impressive Bluetooth suite is built in, offering connection to wireless devices like cell phones and music players. Remote-control functions reside on the attached control unit, and cell phone calls are answered with the push of a single button after being announced by interrupted music and an LED signal. Any Bluetooth device can be controlled from here. Of course, ATC signals are given priority. The headset operates on two AA batteries (lithium preferred) with an average operating life of 40 hours. Bluetooth usage brings that down to 25 hours.


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