Want best speech intelligibility in flight and long term hearing protection? Why I'm switching to ANR from a light foam plug passive headset, and you should too.

[DXB]

I have a modicum of professional background in hearing physiology, though I wouldn't call myself an expert.  When I started flying, I was worried about hearing protection.  Cockpit noise is certainly loud enough to cause noise-induced hearing loss in the long term, and I have a family history of severe hearing loss with aging (termed high frequency sensorineural hearing loss - what makes it harder to converse in a crowded room as we get older).  I got a Clarity Aloft headset with foam plugs (same passive technology as Halo and a couple others).  They were cheaper than high end ANR, and they were much more light and comfortable.  I also believed from a shallow understanding of the topic that they provided equal or better speech intelligibility in flight and long term protection against noise-induced hearing loss. But my high frequency hearing is now on the decline, and parties are no longer fun. I have tinnitus, and I'm thinking about hearing aids while still in my 40s. I also sometimes struggle to understand ATC, and so I decided to dig deeper.  My original reasoning behind headset selection was wrong!

Six key background facts:

(1) The audible frequency range for humans is 20-20,000 Hz.

(2) Hearing in the1000-4000 Hz range is important for understanding speech.

(3) Concurrent background noises, even if below 1000 Hz, still significantly degrade speech intelligibility. 

(4) Loud cockpit noise is almost entirely below 1000 Hz. (Figure 1).

(5) Foam plug/earmold headsets provide superior protection vs. ANR in the high frequencies, but clearly inferior protection vs. ANR  in the low frequency range where all the serious cockpit noise happens (Figure 2).

(6)  Noise induced hearing loss always starts in the high frequencies (save for a couple obscure diseases) - typically starting around 4000-8000 Hz and working its way lower across the human speech range (Figure 3). That is true whether the damaging noise exposure is in the range of speech or below that range. Even loud low frequency noise below the lowest audible frequency (20 Hz) is destructive.   

The takeaway:

(1) If you want a light comfortable headset, Halos, Clarity Alofts, etc. are hard to beat.

(2) If you want optimal speech intelligibility in the cockpit, the ability of high end ANR headsets to cancel low frequency background noise makes them superior.

(3) If you want to protect your hearing from irreversibly damaging cockpit noise, the ANR headsets also seem superior to me.  

 

Edited October 30, 2021 by DXB

[Hank]

I use the silicone plugs with my QT Halos. Quiet Technologies is owned by an audiologist, I trust his education, intentions and product design.

I probably have 700+ hours with Halos, and finally convinced my wife to try a pair last year--it took a single 30-minute local flight to put her DCs on the hat rack for passenger use.

[EricJ]

ANR is a godsend for me, and also my hope of preserving my hearing as long as I can.    I have tinnitus, and am just starting to experience high frequency hearing loss.    None of it is considered very bad yet, but I don't want to aggravate it any more than necessary.

ANR all the way.

 

[N231BN]

I agree with your takeaways, earbuds are not very good in loud airplanes. I don't consider a Mooney a loud airplane.

[carusoam]

I saw an app being used on a new iPhone….

it had a frequency generator…

People around the room were saying if they could hear the sound or not…

the +20k sounds were inaudible to men…. And extra annoying to the ladies…

It may make a great way to test a headset…

The frequency could be swept… or set…

And some sounds could not be determined where the source was coming from…

PP thoughts only…

Amazed by what a cellphone speaker can do….

Best regards,

-a-

[1964-M20E]

Good brief.  I think the QT guy uses the opposite argument that the constant counter energy to cancel the noise is more damaging to your ears.  I do not know one way or the other.

 

I do know that my PPL training was done without any type of hearing protection     I spent too many weddings sitting in front of the band, too many shooting sessions, too many hours cutting 10 -15 lawns a week, too many times grinding and beating on steel, and too many hours riding down the highway windows down and stereo blaring all without hearing or eye protection.  You know cool people don't wear that stuff.

What did you say I didn't hear you?

 

[mike_elliott]

2 minutes ago, 1964-M20E said:

I do know that my PPL training was done without any type of hearing protection     I spent too many weddings sitting in front of the band, too many shooting sessions, too many hours cutting 10 -15 lawns a week, too many times grinding and beating on steel, and too many hours riding down the highway windows down and stereo blaring all without hearing or eye protection.

Not nearly as hard on your ears as a week of listening to my ex..

[1964-M20E]

Just now, mike_elliott said:

Not nearly as hard on your ears as a week of listening to my ex..

That is why men loose the high frequencies first.

[DXB]

5 hours ago, 1964-M20E said:

I think the QT guy uses the opposite argument that the constant counter energy to cancel the noise is more damaging to your ears.  

I don't know what the QT guy has said, but it's hard to take anyone seriously who would make such a claim. It is simply a bald-faced lie if it's coming from someone with even basic understanding of sound physics and hearing physiology. The true believers blabbering on Youtube about this issue seem largely to be scientifically illiterate members the tin foil hat brigade.  The kernel of truth in it is that ANR does not cancel sound perfectly, and a phase error in the cancellation could increase sound intensity under certain conditions - but in reality, this hardly ever happens with modern ANR tech in real world use conditions.  As evidence of cancelling imperfection, one may also cite the faint hiss heard in ANR headphones in absence of external sound - but this very low sound level poses no risk.   Some have also claimed discomfort experienced with ANR in quiet environment as evidence of it being dangerous.  That discomfort largely arises from tinnitus becoming unmasked in very quiet environment - but experience of that high pitched "sound" is a byproduct of our out neural circuitry trying to compensate for high frequency hearing loss, not a result of a real noise reaching the ear.  

One could also legitimately argue that loud sounds outside the efficient ANR range pose greater threat with ANR headphones than passive ones. For instance, the Bose A20 ANR is so efficient at blocking lower frequency noise that they reduce the clamping force of the headset significantly in order to increase comfort.  That reduced clamping force would make them inferior to a simple passive headset in a high frequency noise environment and far inferior to QT Halos and other passive ear canal insert headsets. It also means that if the batteries in your A20s die, they make for lousy passive hearing protection.  But the simple fact is that our planes produce almost all their noise in the ANR range of the A20 and similar products, and so their inability to block high frequencies is irrelevant.  I've read that they may be a suboptimal choice for turbines and radials because of their higher frequency sound spectrum, but I haven't delved into the details there.

 

Edited November 2, 2021 by DXB

[WaynePierce]

This is an interesting thread. I'd considered the halo type before but never moved on them. I've used ANR since I started flying even during PPL training. I'm a late comer to Aviation even though I always wanted to fly and solo'd in a Piper special in the late 70's. No hearing protection then. I've had Tinnitus for probably 30 years and I lost the upper frequencies years ago. (You know that frequency that your wife's voice seems to live) It's funny we have an egg cooker that sounds a high pitch when the eggs are done, my wife, in her office upstairs can hear it going off and alerts me when I'm in the living room next to the kitchen. I can't hear it until a couple feet away. 

Hearing is important, all you youngins' out there, protect what you have.

 

 

[steingar]

Thankfully I could never use the Halo style headsets.  I have abnormally small ear canals, could never get an ear plug that worked.  Would have needed them custom made, blowing the budget.  I like my Lightspeeds just fine, though.

[EricJ]

6 hours ago, 1964-M20E said:

Good brief.  I think the QT guy uses the opposite argument that the constant counter energy to cancel the noise is more damaging to your ears.  I do not know one way or the other.

It sounds like he's selling headsets with misinformation.    It's kind of a dumb statement, but it's not the first time I've seen it mentioned, so it's apparently effective in selling headsets.

[Hank]

6 minutes ago, EricJ said:

It sounds like he's selling headsets with misinformation.    It's kind of a dumb statement, but it's not the first time I've seen it mentioned, so it's apparently effective in selling headsets.

Phil has a Ph.D. in Audiology. I'd trust what he has to say about how hearing works, what causes hearing loss and how to prevent it. Not so the many keyboard geniuses out in interweb-land . . . .

[RoundTwo]

11 hours ago, carusoam said:

I saw an app being used on a new iPhone….

it had a frequency generator…

People around the room were saying if they could hear the sound or not…

the +20k sounds were inaudible to men…. And extra annoying to the ladies…

It may make a great way to test a headset…

The frequency could be swept… or set…

And some sounds could not be determined where the source was coming from…

PP thoughts only…

Amazed by what a cellphone speaker can do….

Best regards,

-a-

Multiple experiments have proven that a person’s hearing loss frequency range is directly correlated to their spouse’s vocal range. Sometimes this hearing loss fluctuates over time and location. It’s worst when sitting in your favorite chair while doing anything you’re interested in. 

[Hank]

2 hours ago, RoundTwo said:

Multiple experiments have proven that a person’s hearing loss frequency range is directly correlated to their spouse’s vocal range. Sometimes this hearing loss fluctuates over time and location. It’s worst when sitting in your favorite chair while doing anything you’re interested in. 

My wife frequently accuses me of having "selective hearing." Now I can just blame it on the plane!

[DXB]

3 hours ago, Hank said:

Phil has a Ph.D. in Audiology. I'd trust what he has to say about how hearing works, what causes hearing loss and how to prevent it. Not so the many keyboard geniuses out in interweb-land . . . .

I'd be curious to hear what Dr. Phil McCandless actually has to say on this topic - I don't see any published public claim by him that modern ANR technology is damaging to hearing, and so I won't personally attribute it to him at this point.  But with caveats I posted above, any such claim would seem extremely hard to defend from first principles, at least for cockpit use. I also looked and don't see any scientific literature to substantiate the claim. Hearing protection is a heavily funded and studied topic in the occupational health realm, and so I'd expect far more research activity on this question even if harm from ANR was merely a plausible but unproven hypothesis. FWIW, I am a boarded otolaryngologist, saw hearing loss patients in a former life, and continue to serve as faculty in an academic department that contains multiple NIH-funded PhD hearing scientists - I'll run the ANR question by them at next opportunity and certainly report back if I've missed something.

BTW I did look up Dr. McCandless' product website and found what seems like a misleading claim:  "Properly inserted, the HALO(tm) is able to quiet the ENTIRE audio spectrum, not just the low frequencies of traditional ANR systems."   Foam plugs attenuate roughly as well as passive over-ear protection in the low frequency range where most cockpit noise occurs; ANR is superior in that range by a wide margin.  The foam plugs may be superior in the high frequencies, but there's just not much high frequency noise in our piston single cockpits.  So the company trademarked slogan "Quiet as ANR - comfortable like nothing else" doesn't really apply to the cockpit sound environment where we are using it.

To be clear - I think Halos are a great product - at least as effective as passive over the ear protection, far more comfortable than any over the ear headset, durable, and very economical - a great value overall.  I only bought the more expensive Clarity Alofts originally because the Halos were on extended backorder.  BUT, if optimal speech intelligibility and particularly long term hearing protection are the priority, then many of us may consider giving up the extra comfort for ANR.

 

[aviatoreb]

I have up on the qt after just a few times in the winter going to my hangar in the winter.  Try sticking a -20F hunk of foam in your ears and see what happens!  Not to mention it does deform to your ear until it warms up which based on ear heat takes awhile.

e

[Hank]

@aviatoreb and @DXB, I despise foam earplugs! But Halos also come with silicone ones (gray in the picture), a very similar design to the ones I wear at work, and they're pretty quiet (blue ones on red cord).

[aviatoreb]

40 minutes ago, Hank said:

@aviatoreb and @DXB, I despise foam earplugs! But Halos also come with silicone ones (gray in the picture), a very similar design to the ones I wear at work, and they're pretty quiet (blue ones on red cord).

Thanks.

I know - I just didn't enjoy them, especially in the winter.  Not quite as bad as foam but still not fun.

[Hank]

1 hour ago, aviatoreb said:

Thanks.

I know - I just didn't enjoy them, especially in the winter.  Not quite as bad as foam but still not fun.

Roll 'em briefly in your (gloved) fingers before putting 'em in. My coldest takeoff with them has been 8°F in West-by-Gawd, Virginny [surely a nice spring afternoon in your neck of the woods! ].

[jaylw314]

Guys, I'm not an otolaryngologist or anything, but if we're going to make claims about what is medically safe, please cite the actual NIOSH recommendations

https://www.cdc.gov/niosh/topics/noise/default.html

https://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf?id=10.26616/NIOSHPUB98126

NIOSH Recommendations:

• The NIOSH Recommended Exposure Limit (REL) for occupational noise exposure is 85 decibels, A-weighted, as an 8-hour time-weighted average (85 dBA as an 8-hr TWA) using a 3-dB exchange rate. Exposures at or above this level are considered hazardous.

More details are in the documentation, but based on old data, the conclusion is that A-weighted decibel level averaged over time is the best measure of hearing loss risk.  A-weighting deemphasizes low frequency sounds, to the tune of 50 dB at 20 Hz, which is consistent with what I recall.  There was also more comparative risk with sudden louder sounds than constant quieter sounds.  While the data is not necessarily widely applicable (the data was from before the days of hearing protection with diverse occupational exposure), there is no other accepted standard of risk measurement, so I was surprised at the claim that low frequency sounds might be more dangerous to hearing loss.  Such a claim would require extraordinary evidence, since it is contrary to the accepted standards.

There's an old AvWeb article about ANR:

https://www.avweb.com/ownership/anr-101-a-tutorial-on-active-noise-reduction-headsets-section-3-airplane-issues/

with the statement

The conclusion was that high levels of low frequency sound could actually be more damaging than the higher frequency noise

However, the context to this statement is that low frequency sound could be more damaging BECAUSE there is more low frequency sound in the cabin.  Such a claim does not mean that equivalent intensity low-frequency sound is more damaging to hearing, nor that there is some mechanism by which low frequency sound is more damaging than high frequency sound.  It does not demonstrate A-weighting fails to predict hearing loss risk in aircraft.

What we need is a good sound profile of the interior of a single-engine aircraft cabin, and the best I could find is this:

It's a terrible image, I know, but it looks dramatically different from the first chart from the Cessnaflyer image, doesn't it?

That's when I noticed the weird notation on the Y axis.  I've never seen dB SPL referenced to 1.0 W/m.  First of all, the unit doesn't make any sense at all, and second, the reference SPL should be 20 micropascals by convention.  And NEITHER shows cockpit noise in dBA.  I think the source of both graphs is from ANR headset companies (the first is from Lightspeed AFAIK).

Anyone have a good sound meter and spectrum analyzer?

FWIW, a quick search on PubMed suggests that other risk factors for hearing loss in adults (cardiac risk factors, toxic exposure) may be as larger or larger than noise exposure, but there's no smoking gun AFAIK.

Edited November 3, 2021 by jaylw314

[EricJ]

9 hours ago, Hank said:

Phil has a Ph.D. in Audiology. I'd trust what he has to say about how hearing works, what causes hearing loss and how to prevent it. Not so the many keyboard geniuses out in interweb-land . . . .

It's not the hearing or how it works, it's what is impinging on the ear, which is physics that happens before that.   If two waves cancel or nearly cancel (which is what ANR/ANC does), what comes out and impinges on the ear is exactly what you'd think, less energy, the same as if it wasn't there in the first place.   It's not hard to explain, and the math and physics behind ANR/ANC is well understood across not just audio, but all kinds of applications.   I did it for about three decades equalizing propagation channels for wireless communication systems.   Adaptive feedback systems are used in many industries and I've only heard such a thing claimed in this case by someone trying to sell a competing system.

[Hank]

34 minutes ago, EricJ said:

It's not the hearing or how it works, it's what is impinging on the ear, which is physics that happens before that.   If two waves cancel or nearly cancel (which is what ANR/ANC does), what comes out and impinges on the ear is exactly what you'd think, less energy, the same as if it wasn't there in the first place.   It's not hard to explain, and the math and physics behind ANR/ANC is well understood across not just audio, but all kinds of applications.   I did it for about three decades equalizing propagation channels for wireless communication systems.   Adaptive feedback systems are used in many industries and I've only heard such a thing claimed in this case by someone trying to sell a competing system.

So then why do my ears pop and feel constant pressure when I press that little ANR button in a Bose headset? And why does that feeling go away when I take the headset off? You know, that funny feeling that passive headsets and Halos don't create? 

[Schllc]

24 minutes ago, Hank said:

So then why do my ears pop and feel constant pressure when I press that little ANR button in a Bose headset? And why does that feeling go away when I take the headset off? You know, that funny feeling that passive headsets and Halos don't create? 

I also have tinnitus and high frequency hearing loss in one ear, and I can’t argue to the science of the affects on the ear because I am no expert.  
But I can tell you if I wear any ANR headset for a 4 hour flight, my ears will ring and physically hurt for two or three days after.  
I have none of those effects with the clarity aloft.   
I also find it much easier to understand atc and passengers than with ANR headsets. (I have tried nearly all of them).  
Lastly, and for me personally there is absolutely not even a comparison to the comfort of the clarity aloft to any over ear headset. 
I would like to see actual evidence that ANR prevents hearing loss or damage to the inner ear, because it would seem neither can claim conclusive advantage with regard to health and it really seems individually subjective as to the efficacy. 

[EricJ]

53 minutes ago, Hank said:

So then why do my ears pop and feel constant pressure when I press that little ANR button in a Bose headset? And why does that feeling go away when I take the headset off? You know, that funny feeling that passive headsets and Halos don't create? 

I've no idea what you're feeling or why, but it isn't the ANR increasing the pressure inside your ear cups.   There is no air pump in your headset that will do that.   If you think there is, just lift the cup a little bit when you feel that to let any pressure out and see what happens.  You may have other things going on.