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 device—and 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.

cotak100's picture

You have to wonder if this technology is so great, why sell it themselves? They could have licensed it to the likes of Sony, and make a bucket load more money.

Personally, I have read said paper and they don't provide the same conclusion as what they are trying to sell. In the end this "device" does not prevent you from losing your hearing. It seems to just minimize your acoustic reflex so you "hear louder" and so you don't turn the volume up. In fact in the NSF fluff press release, they talk all about audio fatigue and not a single word about hearing loss. A fine point they don't talk about in their marketing.

Also, about their so called research. They make a big point to mention the National Science Foundation in their materials. Which IMHO is there to make people think their stuff has been approved by those big brains at the NSF. They conveniently avoid talking about their funding coming from NSF's small business grants which are not exactly the same as the sort of grants and funding given to academic research. Having experience in obtaining government grants for research, I know there can be a lot of leeway. You can get grants for stuff that are for all intent and purpose useless if you write your proposal write and aim for the grants that does not have high value and low levels of review before being granted.

ednaz's picture

I have a set of their A10 custom IEMs with the Adel technology. (Did the kickstarter campaign with them, figured even if the technology doesn't work, I'd still have a nice set of 10 driver CIEMs at a nice kickstarter price.) They sound wonderful. And having listened to many sets of regular IEMs and three sets of custom IEMs over the years, there are some differences I've noticed. After a couple hours of listening with my other CIEMs I feel like I need to take them out for a bit, there's a little stuffiness or veil over the sound that develops, little at a time, and if I take them out for a half hour or so, it clears up. (Long international flights... which is why I got CIEMs to begin with.) I also notice that I do get the urge - and sometimes indulge in - turning up the volume a notch here and there as a listening session goes on, because it just seems to need that. Neither happens with the A10 Adel CIEMs.

Whether or not it's protecting my hearing, I can't say. Maybe after 10 years? But, the lack of that listening fatigue or developing veil, and having the music be fun and engrossing at the same volume when I start and when I finish, make me think something's going on that may well be good for me. That little difference has made me decide that the A10 Adel will be what I listen to for long trips or listening sessions, and my other CIEMs for shorter sessions.

An upcoming replacement insert will be "tunable" so I'll be able to set it for more or less pressure relief, and see whether they are like my other CIEMs when I've got them set for no or low pressure relief. Meantime, they're a really nice sounding setup.

veggieboy2001's picture

Fantastic. That honesty and impartiality is why you are one of the best in the business (IMHO). Some things just take further evaluation (I really enjoyed Brent Butterworth's AudioQuest Nighthawk review for that reason). I am really intrigued by the ADEL technology...I look forward to your thoughts!!

ednaz's picture

I don't notice much of an isolation difference if any compared to my other acrylic CIEMs. When I need isolation I use a set of silicone CIEMs; so I don't really listen to them in a way that really tests it.

As to the reduction in fatigue and acoustic reflex versus preserving hearing, they're linked, in my experience. I have to fight the urge to dial up the volume over time with all my other CIEMs, which is the basis for the preserving hearing statements, I believe. It's ironic that many of my musician friends who have been using in-ear monitors for a long time are as deaf as those who used blasting stage monitors.

ZumbroFilms's picture

I am new to IEMs. The 2nd purchase I made were the Sony XBA-A2 and they are my current phones. The reason for my post is that my first purchase was the Etymotic HF3. This phone fitted deeper into my ear canal and so initially when I began using the ZXBA-a2's I began using the smallest tips. I was not happy with the experience. I found the midrange to be very honky and peaks were uncomfortable. Out of sheer luck really, I tried the largest tips. The difference was dramatic. Gone was the midrange honk and the presentation was suddenly pleasantly well balanced. My guess was (without reading any of this about ADEL) that the phone was designed to play in a bigger volume than the Etymotics and that my ear drum was simply being overloaded when I wore it deeper in the ear. The experience has made me realize that finding an IEM that works in my ear canal is going to be critical. I am getting closer to dropping $$$, so I very interested in the forthcoming review. Hopefully it won't be too long coming!