It’s a tale as old as tech support: an excited customer receives their new Zulu headset, unboxes it, inserts the batteries, fits it on their head, and powers it up. Joy! Amazement! Except…. what’s that soft hissing noise in the background? Is something wrong with their brand-new headset?
ANR (Active Noise Reduction, sometimes referred to as ANC, or Active Noise Cancellation) is a method of reducing or removing unwanted sound through the introduction of second sound wave that attenuates a portion of the first. While ANR doesn’t create absolute silence, it dramatically reduces auditory stress and fatigue caused by engine noise. The effect creates a soft, “white” noise that’s essentially undetectable in the noisy airplane environment for which it’s designed. In a quiet room, however, it’s definitely noticeable.
Here’s a quick guide to help you identify and troubleshoot three common auditory experiences as reported by customers.
Hiss, or White Noise
This is the sound of ANR. When not functioning in a noisy environment, the ANR frequency is noticeable to the ear – this sound is entirely normal and not usually detectible in the plane with the engine on.
This is the term we use to describe a rapid, staccato thumping or rumbling sound that may occur when you tilt your head from side to side, or when something prevents the ear cushion from creating an effective air-tight seal around your ears. This noise is often described by pilots as a low-frequency “machine gun” sound, and the culprit is typically gapping between the cushion and the area below your ear lobes, where your jawbone begins (although this can vary by head shape and ear size). Earrings, thick sunglasses, beanies, long hair, and other barriers can also cause this noise. A tall headpad or removal of the offending item can remedy most of these occurrences.
This noise manifests as a loud, high-frequency, piercing noise sometimes described as sounding like a train whistle. If you’ve ever accidentally pointed a microphone at a speaker while giving a toast or serenading someone at karaoke, you may be familiar with this noise. A squeal can occur in two scenarios:
A.) Transmit Squeal: This is exactly what it sounds like. When you key the mic, break squelch, etc., a squeal is produced. This is usually remedied by adjusting the mic gain, the avionics gain (radio squelch), or the volume control. It can also be caused by a faulty Push-to-Talk (PTT) switch. This squeal can usually be heard through the radio and intercom.
B.) ANR Squeal: An ANR squeal occurs in the ear cup(s) of the headset, and does not transmit over the radio or the intercom. It’s typically caused by an object (ears, earrings, hearing aides) in close proximity to the ANR electronics within the ear cup which disrupts the ANR frequency. Most of these issues can be addressed through troubleshooting, but solutions can depend upon the shape and size of the wearer’s head or ears.
Our passion is to provide a comfortable, safe, and enjoyable headset experience in-flight. We design and engineer wearable technology to support this passion, but the experiences of individual pilots can vary wildly, and the application of our technology may require minor adjustments for ease of use. If you need additional support, reach out to our legendary Customer Support team. Lightspeed Aviation is committed to keeping you flying safely and comfortably!