CanJam at RMAF 2015: 64 Audio and the ADEL Hearing Safety Device
Quite some time ago I wrote an article about the Ambrose Diaphonic Ear Lens (ADEL). I took exception to some of the methods and terminology used in explaining the deviceand frankly, I remain somewhat skeptical of the terminology in the marketing materials used now. However, my intuition tells me there's something to it; I measure far too many IEMs that have an enormous amount of bass to completely ignore the idea. In the time since my first exposure to this technology, 1964 Ears has embraced the idea and is now changing their brand to 64 Audio to signal the important transition to a much safer (their claim) IEM. They currently offer ADEL in both custom fit and universal IEM styles.
The basic idea of the technology is to provide a pneumatic pressure relief diaphragm to prevent over-pressurization of the ear drum at low frequencies. Watching the first couple of minutes of this video (and for additional detail the first half of this video) will save me at least 1000 words trying to explain it. My problem is I don't know how at what point, as it goes lower in frequency, sound transitions into "pneumatic pressure." I spent quite a bit of time with 64 Audio CEO Vitaliy Belonozhko trying to get more clarity on the subject, but still found myself with numerous questions. He mentioned a study done at Vanderbilt University titled "Specific Coupling Can Affect Perceived Loudness in Insert Earphones," so I will be reading up when I get my hands on a copy.
Fortunately, with production units now available from 64 Audio, it's possible to get ears-on experience. I did try one of their U-Series IEMs with adjustable ADEL modules at CanJam. I was expecting a significant loss of bass when opening the valve to permit more pneumatic pressure relief...but I didn't hear that. On brief listen, the IEMs did indeed sound a bit more natural with the valve open than with it shut.
I await review samples with baited breath.