After our post comparing the A20 to a Zulu 3, several of you wanted to have a similar comparison to the David Clark ONE-X circumaural ANR headset. Let’s dive into that.
The ONE-X was a design added onto the original product from David Clark called the PRO-X. That was intended to be a supraural design, which means it fits “on” your ear vs “over”’ your ear, for use in turbine and cabin class planes. It was a very lightweight design that has been a well-received design in the professional pilot market. Initially promoted as a valid General Aviation product, it soon proved to be obviously lacking in the needed attenuation for piston noise spectrum in most planes. As such, the headband system was later adapted to also fit a larger cup strategy…and the ONE-X was introduced.
From a comparison standpoint, let us quickly get through the similarities as compared to a Lightspeed Zulu 3. The control box is similar in features and functions to both the Zulu 3 and A20. Dual volume controls, Bluetooth audio, and “behind the battery” switches to control stereo/mono and auto shut off. Up to 50 hours of battery use time is claimed, in the same range as the other products. Minor premium capabilities that are missing from the ONE-X are a port to plug in a 2nd auxiliary audio device and the selectable ability to mute that aux signal. These are both very helpful options for music listening and piloting.
Examining the headset, it is comparable in weight to the A20 with a small but sturdy design approach to the headband and stirrups. One semi-unique element is the foldability of the design. While the PRO-X has a 70% smaller result when folded, the ONE-X (with the larger cups) gets to 40% smaller. Space matters in a flight bag. The flex electret mic boom with two-sided capability is like the Bose A20. The Zulu 3 is not reversible, favoring instead specific acoustic designs for unique left and right cups to optimize fit and quieting. The ONE-X does NOT have this design for acoustics – a critical trait that affects comfort and limits overall quieting capability (more on that later).
DC joins the A20 in using the standard polyurethane cable/conductor structure in the cables. You might recall the Zulu 3 uses an advance Kevlar-reinforced cable that lays easily and without kinking. That cable is also far more durable, leading to the warranty difference of 7 years vs the 5 years on the ONE-X and the A20. Both of those products are, however, TSO certified.
So, substantially they are all similar in many ways. The two main areas of difference would be the fit/comfort of the ear seal/cup design and the overall quieting performance. While extremely light and with reasonable side pressure, the ONE-X ear seal is designed in the old style way of surrounding your ear instead of creating comfortable room for your ear. Given the adapted use of the PRO-X headband system, the design of the larger circumaural cup systems was limited in ways that show up in several marginalized comfort and quieting metrics.
Comfort and wear-ability
First, let’s talk about its circumferential size – it’s smaller than needed. For many people with average and bigger ears, the ear does not fit fully inside the seal. This typically means it is either squished some by the seal or is wiggled in and therefore touches the seal for the duration of the flight.
Secondly, the volume/space for the ear Pinna is not well considered. This is partially like the first issue, but the pinna (the flappy part behind/above you ear canal) protrudes from the head at least ½” on average. For the pinna to float comfortably in the ear seal, the seal and cup must be designed for that. That was not fully considered with the ONE-X. The Zulu 3 design has 60% more room than the A20 and over TWICE the volume designed in for the pinna as compared to the ONE-X.
Finally, the ear seal surface area and overall design is far from optimal. The actual surface area for the seal to seal comfortably on your head is 35% smaller in the ONE-X design. Given the importance of a good seal for effective ANR, this means greater side pressure is needed to insure a good seal. If you wear glasses, the surface area that can seal around your frames is nearly twice as much on the Zulu ear seal. More seal surface ultimately leads to lower temple pressure from the headset.
Quieting performance
As noted above, the headband system was designed to support a reversible design for the boom and cord. That meant the well-proven techniques for optimizing the ear into a specific cup were off the table. Lacking the ability to design the cup for the unique characteristics of a left ear vs a right ear also sub-optimizes what can be done for active quieting. The ear openings of our heads are not positionally reversable. To properly correlate the ear opening to the position and performance of the feedback mic and anti-noise speaker in the ANR system dictates a less effecting cancellation result. That is a consequence of other design choices.
As a result, the active quieting is credible – but not incredible. On top of that, the passive performance of the ONE-X (along with the A20) is markedly lower than the Zulu 3 design in the important 50-500hz noise range. Virtually everyone who does a side-by-side comparison notices a difference immediately. It’s not terrible, but not to the quieting levels of the Zulu 3 in a piston noise setting.
So, the ONE-X has a sturdy design from a trusted brand with a few different features but some design compromises. Priced just $45 higher than a Zulu 3, it is just hard to compete with more quieting and likely a more comfortable wearing experience. If you can, I would encourage you to do your own comparison since comfort and hearing acuity are very personal.
Does this post help clear things up for you? Let us know your thoughts and questions by commenting below.
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