Learn more about ANR
The Lightspeed Aviation engineering staff wrote two tutorials about Active Noise Reduction in General Aviation. ANR 101 is a five-part series about the basics of ANR, acoustic issues, airplane issues, ergonomic and interface issues, and optimizing your flight experience. ANR 201 is an in-depth series about the factors that make a headset "quiet," passive versus active noise reduction, the trade-offs with different manufacturers' designs, and specifically to ear cavity volume and ear seal design/comfort. We hope these tutorials help you make an informed selection.
|·||How does the ANR work?|
|·||Do all ANR headsets work the same?|
|·||With the ANR on, can I still hear my engine?|
|·||Are Lightspeed headsets compatible with other headsets and intercoms used in general aviation?|
|·||What kind, how many, and how long do the batteries last?|
|·||What happens if my batteries run out during flight?|
The ANR microphone, located inside the dome, senses noise frequency and amplitude at an instant in time. The Active Noise electronics process that noise and relays it to the speaker driver. That speaker adds a signal that is 180 degrees out-of-phase with the initial noise sensed by the microphone. Those two signals sum to zero, canceling each other out. For more information on this subject, please refer to our ANR 101 tutorial.
In general, they all utilize the same acoustic theory of 180 degrees out-of-phase signal to cancel engine noise. In truth, performance varies significantly among active headsets. It is important to compare them with technical specifications and in actual flight. Manufacturers make a variety of trade-offs in dome cavity design, ANR mic position, electronics complexity, ear seal size and shape and materials in developing a product. Many are constrained by an existing passive design, leading to sub-optimized efficiency and effectiveness. Ultimately the headset delivers a curve of cancellation that can be characterized by: depth, breadth and position of cancellation. Manufacturers should be able to supply you with that information.
The noise we're canceling with the ANR circuitry are low frequency propeller, exhaust and wind noise that register at about 100Hz in the cockpit noise spectrum. True engine noise is higher up the spectrum, and believe it or not, you will more likely hear the engine better.
Mechanically and electronically they are compatible. Our headsets use the
standard 2-plug interface and have an electret, noise-canceling microphone.
Keep in mind that various passive headsets sound different based on the
speaker effectiveness and microphone sensitivity. That "sound" is
further modified when the active circuitry is turned on, since the audio
levels and the signal-to-noise ratio are changed, which makes comparisons
difficult. This is even true of Lightspeed headsets.
We even provide
enhanced audio clarity in the ANR mode, and elevated signal levels. Both
provide additional clarity for easy listening and safe communications. The
microphone frequency response was adjusted to preferentially emphasize the
voice range. The sound profile and output level of the mic might be somewhat
different from other headsets you have tried. Adjustments can be made in your
intercom squelch setting and individual mic booms can be positioned for
Zulu PFX takes four AA batteries and can get up to 20 hours, depending on Bluetooth usage. Sierra, the original Zulu, and Zulu.2 take two AA batteries and can get up to 40 hours of battery life, depending on Bluetooth usage. The 30-3G will last for up to 30 hours with two AA batteries, depending on how noisy of an environment it is in.
If you lose power at any time, the headset will continue to perform as a passive headset. Our products utilize independent circuitry for Comm Audio and ANR cancellation to ensure this. It can be frustrating to lose your active performance while flying. All of our active headsets come standard with what we call a "Fuel Gauge" that allows you to monitor the battery level at any time. We recommend you add checking your batteries on your preflight checklist. Of course, the 2 AA batteries can be replaced at any time even in flight. That's a big advantage over rechargeable systems that require downtime before their active system can work again.