Say Again? - A general headset review

When I learned to fly ...

It is difficult for me to imagine flying without a headset, but that's how pilots use to fly. Ask around, those who learnt to fly twenty or thirty years ago can tell you that many aircraft didn't even have intercoms. Actually, you can still find aircraft where your only option is to wear ear plugs, turn the cabin speaker to max volume, grab the microphone and say "Say Again?" Even glider pilots wear headsets today, simply because they want all hands available for manipulating the aircraft's controls. Makes sense ...

Needless to say, the advent of aviation headsets and intercoms was a revolution to communicating within controlled airspace, but also improved operations at uncontrolled airfields. I wonder how many pilots never ventured into controlled airspace simply because of the difficulty of communicating without a headset. I know that if my headset were to malfunction, at the very least I would try and stay outside of controlled airspace, not to mention squawking 7600. The most challenging part of my flight training was learning radio communication and phraseology. It took me some time to make sense of what those voices were saying. Still today, if you don't anticipate what a controller or a pilot might say, then you're "Saying Again" repeatedly.

Just take anybody, who isn't a pilot, up with you, give them a pad and pencil and ask them to write down everything they hear. Now add a bit of turbulence and you have just discouraged them from learning to fly!

So, apart from the obvious (an airworthy aircraft), an airworthy headset is crucial to interacting with pilots and air traffic controllers, not to mention preserving your hearing, right? Say again?

What should I be looking for?

Here goes: there is no perfect headset, not yet anyhow. I'm serious, at PilotShop.com we sell dozens of headsets to customers every month and I have learnt that everyone's needs are different. You're right though, their wants are often the same. For instance, many pilots will come to our shops asking for the same brand or headset. With 40 headsets on display, even those who are loyal to a brand will end up trying on a few different ones, at least to confirm their choice. Just as many, end up buying something completely different, realizing a different headset fits better, performs better or simply matches their needs. What should you be looking for? Well for a start, understand your needs and your wants (yes, it is ok to want), and find the headset that performs best accordingly. Enjoying a headset starts with feeling good about what you are purchasing. Here are two extremes:

- you buy a thousand dollar headset and every time you wear it you feel guilty about the $100 gift you got your significant other for their birthday, while your mind is erring, the controller says something. You say "Say Again?";

- you buy a headset that is not meeting some of your basic needs, you are uncomfortable, your ears hurt and your are going to have to shorten your flight because you can't stand it any longer.

I have seen both cases and everything in between. There are enough inherent distractions to piloting an aircraft, you don't need more!

Compatibility

Some headset requirements are obvious, nonetheless I will just mention that your headset needs to be compatible with the intercom in the aircraft you intend to fly. Compatibility means, that the headset has the right plugs, dual general aviation, single military or helicopter, just to name a few. Is the intercom low or high impedance? High impedance is the standard for general aviation (fixed wing and helicopters), whereas low impedance characterizes military aircraft such as C130s. The main difference is the mic, which will not function properly if used in the wrong aircraft. Actually, many pilots using military issued headsets make the mistake of thinking that a single military plug to dual general aviation plugs adapter will do the trick. Actually, a low to high impedance (or vice versa) adapter is needed to convert the signal for the mic to function.

That was easy, now for the challenging part, your needs.

Comfort

Comfort is important, but subjective, everyone has a different threshold for discomfort (or pain, you can tell where I stand on this particular issue, I have sensitive ears, really!) Trying on a headset in our shop is obviously great, but trying it in the cockpit the next time you fly is best. How long do you usually fly? If you make short flights, you might not feel the need for extra amounts of precautionary comfort. On the other hand if you make long flights, you want to make sure your head is not buzzing in the third hour of your flight, as you are getting ready to execute an approach in Instrument Meteorological Conditions.

The most common complaints about discomfort originate from clamping, weight and fit. Clamping happens when a headset is too tight around one's head, typically having a squashing effect on your ears (and temples if you wear glasses). Clamping is generally required to create an effective seal around your ears. Metal frames, such as on most AvComm, David Clark and Flightcom headsets, tend to clamp more than other types of construction such as wire or composite frames. This tends to create more discomfort while at the same time making a more effective seal and, hence, rendering more effective noise reduction. Depending on how strong your neck is, and again, how long your flights are typically, headset weight can be a contributing factor to discomfort. There is obviously a difference to wearing a headset that weighs 11 ounces and one that weighs almost a pound and a half, especially if you are pulling Gs. It is also possible you prefer to feel some weight so that the headset sits firmly on your head. Finally, fit is an essential consideration. Most headsets come in a single size with adjustable headbands and a standard size earcups. Let's just say that if you have smaller than average ears (like myself) then you will probably be alright. Some headsets like David Clark's H20-10 and Flightcom's Denali series are ergonomically designed to improve fit around ears and head. Ear comfort tends to be the overwhelming origin of discomfort as head size is not really an issue unless you have a small one, but everyone knows that pilots have big heads! Comes with the territory.

So you've more or less determined how sensitive your ears are and you have a few ideas already. Ear seals can make a huge difference. Three types of ear seals exist in the market, plus the possibility of using ear seal covers. The first and most common type of ear seals are vinyl covered foam. They're less expensive to replace, but don't leave them in the heat or the foam bakes and eventually flattens to the point where they become "ear crepes". Foam seals tend to go hard in the cold, so you'll need to warm them up for 15mn (by wearing them of course, don't use the engine heater or exhaust) before they flex into position on your ears. Gel seals are vinyl ear seals filled with liquid gel instead of foam. This type of ear seal suffers less from hot and cold situations, while adapting better to the shape of your ears. The only unpleasant thing about gel seals is sweat and consequent slippiness. Inadvertantly puncturing them doesn't help either, then the gel slides down the side of your neck and all over everything else (you can tell I have experienced this). The third type of ear seal is leather or imitation leather, which provides more comfort and a natural feel, but a poorer seal. The softer foam inside the leather outer skin is less dense than in other types of ear seals. To add to this, the outer leather skin, typically has sinews (cracks, ripples) that provide a way for noise to seep in. Consequently, headsets with leather ear seals generally achieve less passive noise reduction.

Performance

A headset's performance is mainly judged on its ability to reduce noise. Aircraft noise has three components: engine noise, propeller noise (if equipped) and air flow noise. Air flow noise? Really? Absolutely, talk to a CRJ pilot. Air flow over the cockpit is extremely noisy in that type of aircraft, whereas the aft position of the engines makes this type of noise less problematic. No props on CRJs. For the common pilot, i.e. single-engine propeller airplane pilot, a headset must effectively reduce engine and propeller noise. Air flow noise can hardly be noticed when flying at speeds below 200 kts unless you lose your engine. Guess which one is noisiest, engine or propeller? The propeller. So what we are talking about is headsets that reduce low frequencies associated with engine and propeller noise. Guess why you want to hear high frequencies? Passengers scream? No. Most audio alarms in aircraft, such as stall horn or gear up horn are high frequency noises that can be heard even if the volume of engine and propeller noise is high. Noise reduction can be achieved in two manners: Passive Noise Reduction (PNR) or Active Noise Reduction (ANR).

The first, Passive Noise Reduction, is simply achieved by putting a headset on, preventing a certain amount of outside noise from reaching your ears. The effectiveness of PNR relies solely on the seal's tightness around your ears. Depending on the quality of materials used, design and fit, a passive headset can achieve anywhere between 20 and 30 dB of noise reduction. Some achieve less, like Flightcom's F20 which is designed to be worn with ear plugs in order to achieve 30 dB of PNR or worn without ear plugs for less noisier aircraft environments.

Active Noise Reduction, is a little more complex, but not much. Imagine sound is a wave, actually it is. Noise is therefore a wave that oscillates at different frequencies. ANR headsets produce an opposite wave for the lower portion of frequencies in effect counteracting engine and propeller noise. This opposite wave is produced electronically. An ANR headset detects, through exterior mics, the level and frequencies of aircraft noise and then emits opposite noise through speakers built into the ear cups. Power is therefore required to operate an Active Noise Reduction headset. Typically, a headset will be equipped with a battery pack designed to take AA or 9V batteries. Some have rechargeable Ni-MH batteries to avoid the expense of changing batteries. Several manufacturers offer panel powered options, i.e. where the headset obtains power from the aircraft and typically requires a specific installation. Sennheiser has an interesting accessory for its HMEC 300 and 400 headsets. The accessory is an adapter enabling one to power the headset from a cigarette lighter, typically found in most general aviation planes (I've always wondered, did people really smoke in the cockpit? What about visibility?).

ANR can produce up to 25 dB of extra noise reduction. However, the more noise the headset cancels electronically, the more power it uses, requiring either heavier battery packs or reducing battery life. Unless, of course, power is obtained from the aircraft (which typically means you have your own and have gone to the trouble and expense of having panel power installed). Typically, the manufacturer determines a power level for ANR output as a compromise between battery life and level of noise reduction. For instance LightSpeed makes two versions of the 3G headset, one called Twenty 3G and the other Thirty 3G. Both are identical headsets to the exception of the power settings. The Thirty produces 6 dB more active noise reduction than the Twenty model. Yes, you guessed right, the batteries don't last as long in the Thirty as they do in the Twenty.

Do you know this cruel trick? Take someone up for a ride who doesn't know about ANR. Then half way through the flight while you are distracting them by pretexting you can't hear them very well, turn on their ANR and then say "What just happened? What's wrong with the engine?" Please don't do this to people who could potentially take up flying, you would be hurting my customer base.

Just one more thing before I move on to talk about audio quality, make sure before you choose an ANR headset that you realise what kind of noise levels you will be subject to if battery power were to fail in flight and you didn't have replacement batteries with you. Pilots will often say "When you go ANR you never go back!" and this demonstrates how easy it is to get used to the added comfort of ANR. The danger here is that you get so used to ANR that when your batteries fail and you forget your replacement ones and you are 45 mn into a 3 hour flight, you are necessarilly going to be subjected to an unfamiliar noisy environment. This is all the more true for ANR headsets that otherwise offer poor passive noise reduction. I fly a 182 RG which has a noisy prop and a 235 hp engine. I typically wear the Sennheiser HMEC 25 which I appreciate for its light weight and powerful ANR. It achieves just under 30 dB of total noise reduction with ANR on. Now I could achieve similar total noise reduction with a heavier and cheaper PNR headset, but I prefer comfort over performance. However, the day my batteries ran out (two AAs) I was only getting 10-12 dB of passive noise reduction. "Say Again?"

Audio quality is not often mentioned instore, but should be. Headsets' speakers and mics will vary considerably in transmission quality. Recently, I had a customer prefer Flightcom over David Clark, simply because the Flightcom volume could be set louder and that was important to him. Mic quality can also be an issue, I prefer not to have to repeat myself. Mics will all work, but the clarity of your voice will vary from metallic, to crystal "747" clear. Well you know what I mean. Ever wondered why the mic doesn't transmit aircraft noise? Well, first of all, not all mics do this. Some, like Plantronics commercial aviation headsets, transmit everything in the cockpit, that's why you can often hear everything going on inside the cockpits of large jets as opposed to general aviation aircraft. Obviously, 747 cockpits aren't very noisy compared to small planes, so there is no need for what are called electret microphones that cancel out ambient noise. These mics are found on most general aviation headsets. First, you must place your mic within 1/4 or 1/2 inch from your mouth. Second, there is an opening on the front of the mic. What this does is let ambient noise in from the front, which then cancels out ambient noise coming through the back. The difference is your voice, which is transmitted free of aircraft noise.

Other features

Stereo and Dual Volume controls. For one, is your hearing balanced? Do you hear the same in the right and left ear? If not then you might want to consider a headset that has dual volume controls. Most Stereo capable headsets have dual volume control (except some Sennheiser headsets). By the way, if you are considering either of the David Clark H20-10 or H10-13.4 headsets, add $5 and you get stereo, and hence, dual volume controls included.

Cell Phone/Music capable. Did you know that some headsets enable you to plug in your cell phone or music player and use them through your aviation headset? I've tried it and it works. I won't say where and when, just in case some FCC people are eavesdropping.

Remember, fly safe and have fun!

Robert Devine
robert@pilotshop.com
Owner of PilotShop.com