Hear all about it

Perhaps nothing identifies a pilot more than the headset. However, a headset is a necessity, not just a gadget carried from lesson to lesson and airplane to airplane. A headset has two major components: the headphones through which you hear, and the microphone that transmits your voice.

The cockpit of a general aviation aircraft can be a very noisy place, so headphones play an important role by enhancing hearing now, and protecting hearing for the future. The racket of a reciprocating engine, the vibrating airframe, and the noise of rushing air all interfere with communication. Radio communication with air traffic control, conversation with a flight instructor, and banter with other aircraft occupants are compromised. We can debate the benefits of hearing or not hearing your spouse well, but in most cases the better we hear, the better we understand. Straining to make out someone's voice diverts attention from other flying tasks. In addition, prolonged exposure to a high-noise environment is extremely fatiguing, whether there is anything being communicated or not.

Online Buyer's Guide Armed with the suggestions in this article, research your headset purchase before you buy. Visit AOPA's buyers' guide of headset manufacturers and companies that sell branded headsets. Then visit their Web sites and talk to company representatives to learn more about their products.

A good headphone should decrease the ambient noise that you don't want to hear and amplify the voices that you do want to hear. However, there is a long-term and more important benefit: hearing preservation. High-time pilots who did not use hearing protection consistently during their careers have impaired hearing. Some older pilots have asymmetrical hearing loss, as they may have worn a headset for years covering one ear to hear air traffic control, leaving the other ear uncovered to hear their crew.

The simplest hearing protection device is an earplug. These are cheap and effective, and they can be combined with a headphone or incorporated in a headset design. Putting plugs in your ears decreases the volume of sound reaching the inner ear, and therefore protects the ear. However, pilots often question whether plugs also decrease their ability to hear the spoken voice. The answer is that ear plugs improve voice discrimination. In a high-noise environment inner- ear sensors are overloaded and respond by decreasing sensitivity. Therefore, you hear less. This is easily demonstrated in a high-noise environment--simply plugging your ears with your little fingers will allow you to hear conversations better.

The second type of hearing protection is that afforded by the earmuff or ear cup. When properly designed, these are particularly effective in diminishing high-frequency noise entering the ear. However, they allow low-frequency rumble to pass. As high-frequency sounds are the most injurious to ears, ear cups are appropriate for use in high-noise environments like a cockpit and are properly worn by ground personnel parking aircraft. However the low-frequency rumble remains and may interfere with conversation. Of greater concern is the fact that low-frequency noise can be very fatiguing--especially on longer flights.

There are two solutions. You can wear earplugs under earphone cups, which is a practical and inexpensive way to enhance headphone performance. Or you can purchase a headset, generally more costly, with active noise reduction (ANR). Electronics contained within ANR headsets produce an "anti-noise" 180 degrees out of phase with ambient noise. When the two noises are summed, they cancel each other. ANR is most effective in the lower frequency range and thus forms a good match with an ear cup design.

When I began training, I did not own a headset, and I used the handheld microphone installed in the Cessna 150 that I rented with an instructor. The mic was always falling to the floor, and I would retrieve it hand over hand using the coiled electric cord. One instructor suggested that I grip the microphone and yoke simultaneously with my left hand, leaving my right hand free to manipulate the throttle, carburetor heat, and flaps. That disturbed my already uncertain yoke technique. A student pilot friend suggested that I drape the microphone cord over the yoke for easy access. I tried that and the microphone still migrated to the floor, but now had to be disentangled from the yoke. My instructor was not pleased with the thought that I might foul the controls.

Handheld microphones are dinosaurs. While they may serve in an emergency, I cannot recommend them for serious flying. When frequent radio communications are required, a boom mic--standard on aviation headsets today--and a push-to-talk (PTT) switch are indispensable items. Depending upon the aircraft you fly, you may have to purchase a portable PTT switch. However, most modern aircraft have a communication button on the yoke, and strapping an accessory switch to the yoke horn is unnecessary.

Most aviation microphones are noise canceling. This is a passive function, accomplished by leaving open the front and back sides of the microphone. The microphone tends to cancel noise it receives simultaneously from front and back, but transmits voice received from the front only. To maximize this effect, the face of the microphone should nearly touch your lower lip. Placement of a microphone is critical to exclude ambient cockpit noise as best as possible. Leaving a microphone a distance from your mouth greatly reduces the quality of transmissions. The same placement recommendation applies to handheld microphones.

If lot of air blows in your face when you fly, you should also consider using a microphone muff--a foam-rubber cover that helps to exclude moving air noise. This does not only apply to flying in an open cockpit, as an open air vent directed toward your mouth will similarly disturb communication. Mic muffs are included with most new headsets.

What you pay typically determines the microphone quality. The cheapest microphones are carbon based, and typically sound scratchy. Better microphones are dynamic (with a moving coil), and the best are electret (with a charged plate). Pilots usually do not choose microphones separately, but accept whatever comes with their headset. The more critical decisions concern the headphone.

Comfort, weight, ear seal, passive versus active, and cost are the factors to consider. Comfort is individual, like the fit of a shoe, and if a headset does not feel right, do not buy it. A pilot should try several headsets. For some pilots weight is an overriding factor. However, a well-padded headband and soft earmuffs--perhaps gel- or liquid-filled --go a long way in relieving the feeling of weight.

The ear seal is important. If your ear is not well sealed by an in-ear plug or an external cup, the earphone will not function properly. When the proper seal is made, there is a definite change in the quality of external sound. If this does not happen when you don a headset or insert earplugs, they will attenuate noise poorly.

To maintain a good ear seal, cup headphones must exert some pressure, called clamping, against the side of your head. In the full cup design, your external ear should fit completely inside the cup without being folded or crushed. Pressure should be exerted about the ear against the skull. The external ear or pinna does not tolerate prolonged focal pressure and will develop an uncomfortable hot spot. Gel- and liquid-filled donut seals are effective in creating a good seal and distributing clamping pressure over a broader area.

Some headset brands have smaller ear cups that are meant to sit on the external ear, and not surround it. Clamping must be much lighter to remain tolerable, and coupled with the small cup design these generally have much poorer noise attenuation. However, when active noise reduction and/or ear plugs are added the result may be satisfactory for quiet aircraft. They are commonly used by pilots of pressurized and turbine aircraft, which by their nature have quieter cockpits than do piston-engined aircraft.

A new type of headphone offered by several manufacturers features earplugs with built-in speakers. Noise is passively attenuated by the earplugs, and radio transmissions are enhanced by placing speakers inside the ear canal. The result is an extremely lightweight headset with little clamping pressure. The tradeoff is that pilots must accustom themselves to well-sealed earplugs. As ear canal shapes can vary considerably between individuals, some brands supply several plug sizes, and others provide custom-mold ear inserts for each pilot.

The benefits of active noise reduction are audible. Noise seems to dissolve when the electronic circuits are activated. Several active noise-canceling headsets I tried were clearly worse compared to a good passive set, until the electronic noise canceling was turned on. This demonstrates that noise canceling works in conjunction with lighter, less-efficient passive headsets to provide satisfactory protection. Remember that adequate hearing protection does not require noise canceling, so the decision to purchase electronic headphones is based on personal likes.

Noise-canceling headsets do require electrical power. You may need to feed the headset batteries, although some have built-in rechargeable batteries; in some cases you can install a dedicated connection to aircraft power, although this may not be feasible unless you own the aircraft you're flying. I carry a small box of batteries with me to feed the headsets in my airplane. Some headsets have battery-saving circuits that automatically turn off the electronics when ambient noise ceases at the end of a flight.

Some headsets boast the ability to attach to cell phones--cell phone use in the air is prohibited by regulation, but they're handy if you want to call someone immediately before you take off to say you're on your way. Some headphones accept stereophonic sound, which is a pleasant way to listen to music while aloft, but does nothing for monaural radio communications. Headphones with separate volume controls for each ear are advantageous if you have a weak ear, but probably of little benefit to most.

An intercom also is an extremely useful tool. However, this requires headsets for all, as well as a portable intercom if one is not installed in the airplane. An installed system has big advantages over portable systems with the rat's nest of wires, black box, and batteries. However, if you are concerned with clear communication within the cockpit, an intercom is the answer. Intercom options like automatic muting when radio calls are received, and voice activation are issues to be considered.

You can expect to spend $250 to $1,000 for a good headset. Top-brand headsets have long lives, and their life is extended by readily available replacement parts, repairs, and overhauls. It is not unusual to need several sets of ear seals, a mic, and a set of replacement wire leads during a decade or more of headset ownership and use. There are even aftermarket mods for established brands.

As you will likely use the same headset for years, consider the warranty details. Some headset manufacturers have an established fee for repair/overhaul, and some have very liberal replacement, upgrade, and repair policies. One well-known manufacturer offers a five-year warranty that is very liberally interpreted to benefit the headset owner.

Speak to pilot acquaintances about their experience with various brands. You will learn that a good headset is a good investment. I advise you not to fly without one.

Dr. Ian Blair Fries is a CFI, senior aviation medical examiner, and ATP, and holds a Lear 35 type rating. He serves on the AOPA Air Safety Foundation Board of Visitors and is cochairman of the AOPA Board of Medical Advisors.

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Links to additional resources about the topics discussed in this article are available at AOPA Flight Training Online.