My Sunday evening Why Question: Helmets and Noise Cancellation?

[gotfog]

I try to limit myself to 3 or fewer "why" questions each day, as for the most part I find it futile. But...

Why has not Bose, of Sennheiser, or someone put together a true state- of- the- art Motorcycle helmet, that already has noise cancellation and speaker capability built in? It seems to me that there exists a true niche between the two and no one seems to have filled it yet.

Anyway, ride well.

John

 

[markaz]

Not enough demand to make it worthwhile.

 

[36654]

I try to limit myself to 3 or fewer "why" questions each day, as for the most part I find it futile. But...

Why has not Bose, of Sennheiser, or someone put together a true state- of- the- art Motorcycle helmet, that already has noise cancellation and speaker capability built in? It seems to me that there exists a true niche between the two and no one seems to have filled it yet.

Anyway, ride well.

John

1. Demand

2. Technical challenge - Turbulent wind noise isn't a discreet frequency easily mitigated by noise cancelling techniques.

You would think that the military would have a need for such a device, but that doesn't seem to be the case.

 

[vtbob]

Good question

I'm not fully sold on the idea of "noise cancelation". Maybe some one can help educate me.

It is my understanding that true noise cancelation, senses noise, it's frequency and amplitude and generates, essentially instantaneously, a sound signal that is identical but 180 degrees out of phase. This is all possible by micro electronics, digital signal processors and great little speakers.

What puzzel me, aside from making this all work right, is the fact that you have a high level of original noise energy, say 100db....then you add to that an identical amount of out of phase energy, another 100db.....if there is a slightest mal function...the phasing is not right, there speaker pops...you ear get a double dose of noise. Not so good!!

 

[lkchris]

These days it should include Bluetooth capability, too.

 

[lkraus]

These days it should include Bluetooth capability, too.

Bluetooth would be essential.

There may be a legal issue here. Effective noise cancellation would almost certainly require headphones which I think most (if not all) states prohibit for both ears.

Even with earplugs and in-helmet Sena speakers (which apparently are legal), I can hear a car in the adjoining lane as it approaches and passes me on the freeway. This is an important sound to hear, to maintain awareness of my traffic situation. How could that gradually building sound be distinguished from simple wind noise, so as not to be blocked?

 

[gotfog]

1. Demand

2. Technical challenge - Turbulent wind noise isn't a discreet frequency easily mitigated by noise cancelling techniques.

You would think that the military would have a need for such a device, but that doesn't seem to be the case.

I tend to think there is demand. The Wireless, Bluetooth, Phone, GPS, Music, Noise, Earplug dialogue exists, it seems that unifying the process is the next logical step.

I'll admit to the technical challenge though, I am no physicist. But there is already a crop of aviation noise-cancelling headsets, that can dance between various inputs; adding a helmet does not seem insurmountable, and the noise cancelling capabilities a derivative of current technology.

One can only hope.

 

[PGlaves]

New helmet: $12,956.27 coming right up folks. This for a group that thinks $5/quart oil is too expensive.

 

[alegerlotz]

Bluetooth would be essential.

There may be a legal issue here. Effective noise cancellation would almost certainly require headphones which I think most (if not all) states prohibit for both ears.

Even with earplugs and in-helmet Sena speakers (which apparently are legal), I can hear a car in the adjoining lane as it approaches and passes me on the freeway. This is an important sound to hear, to maintain awareness of my traffic situation. How could that gradually building sound be distinguished from simple wind noise, so as not to be blocked?

As I frequent business traveler, I have far too many hours in noise cancelling headphones... They work well with constant noises such as the hum of the engines and similar sounds, but the crying baby or chatty kathy is easy to hear.

I wonder the same thing about the vehicle next to you... I would think that sound of a car coming up would get mixed in with the wind noise and motorcycle engine sounds that the system would be attempting to eliminate.

 

[Cessnadog]

In the aviation world ANR headsets have become the norm. Cost ranges from about $600 to $1200 depending on the bells and whistles. Headsets without the noise cancellation run $350 to about $650...

This is clearly doable.
Matter of cost and demand.

 

[lkchris]

New helmet: $12,956.27 coming right up folks. This for a group that thinks $5/quart oil is too expensive.

Yeah, my helmet was $6-700 and it has a $400 Bluetooth unit attached to it and sometimes I stuff my $200 gloves into it.

I carry it with me or lock it in a saddlebag. None of that silly hang it on a footpeg stuff.

 

[greenwald]

Bluetooth would be essential.

There may be a legal issue here. Effective noise cancellation would almost certainly require headphones which I think most (if not all) states prohibit for both ears.

Even with earplugs and in-helmet Sena speakers (which apparently are legal), I can hear a car in the adjoining lane as it approaches and passes me on the freeway. This is an important sound to hear, to maintain awareness of my traffic situation. How could that gradually building sound be distinguished from simple wind noise, so as not to be blocked?

Please see: http://www.americanmotorcyclist.com/Rights/State-Laws.aspx

 

[36654]

In the aviation world ANR headsets have become the norm. Cost ranges from about $600 to $1200 depending on the bells and whistles. Headsets without the noise cancellation run $350 to about $650...

This is clearly doable.
Matter of cost and demand.

1) How many times do you change speed in your Cessna?

2) Set your noise cancelling head set next to the window and see how well the noise reduction works with a direct path to ear. Better yet, set at the back of the plane and put your head set next the cabin wall.

Turbulence is wonderful thing and those foam plugs are hard to beat.

 

[Anyname]

I have a set of Bose "in the ear" headphones which are amazingly effective. I'd pay for a Schuberth with electronic noise suppression. Fooling with ear plugs every time I ride is a PITA.

 

[nickrides]

Those Bose noise canceling headsets are about $300.
I wonder what it would take to take one apart and install it into a helmet.
I've had a ANR headset for aviation for many years and they are amazing. You can easily converse with someone who is not wearing one.
They just take the harsh tones out and mute the ambient noise to a fair degree. Awesome technology at a reasonable price.

 

[BC1100S]

Turbulence is wonderful thing and those foam plugs are hard to beat.

A more cost effective solution would be hard, if not impossible, to find

And, if you feel especially flush, you could opt for those custom-moulded ones for about $100.

 

[jcj78]

1) How many times do you change speed in your Cessna?

Every time I get to the end of the field.

2) Set your noise cancelling head set next to the window and see how well the noise reduction works with a direct path to ear. Better yet, set at the back of the plane and put your head set next the cabin wall.

Turbulence is wonderful thing and those foam plugs are hard to beat.

You ride with your helmet pressed firmly against the frame of the motorcycle?
No one wears a helmet in a Cessna 172. Helmets are for working airplanes, where your head is getting bounced off the inside of the cockpit as you manuever. Some are even open cockpit, and lots of Ag Cat and Weatherly pilots fly with no doors, so VERY comparable to a motorcycle.

 

[36654]

Every time I get to the end of the field.

You ride with your helmet pressed firmly against the frame of the motorcycle?
No one wears a helmet in a Cessna 172. Helmets are for working airplanes, where your head is getting bounced off the inside of the cockpit as you manuever. Some are even open cockpit, and lots of Ag Cat and Weatherly pilots fly with no doors, so VERY comparable to a motorcycle.

I said "Head set"........Not Helmet.

So you're in the slipstream or wash of the prop and likely behind the windshield...........the adaptive circuit can adjust to the primary low frequency noise. In your case, I'm guessing a 3-blade prop turning at 3000-rpm. That's a wake interaction at 150-hz. Otherwise, you're benefiting from the ~23 dBa NRR of a head-phone with a solid ear cup.

Adaptive control targets annoying low frequencies, but that doesn't mean dBa noise reduction. If you want to retain your hearing, dBa NRR is what you want to be concerned about.

 

[jcj78]

You did say headset. My bad.

I am in an enclosed cockpit, so my ride is not as comparable. Two blade prop here, redlines at 2750 and is turning between 2500 and redline while I'm working. In a 'Cat or Weatherly you'd be sitting behind a R-985 or R-1340, probably also spinning a two blade at around 2700. But there you'd have no more "slipstream" effect than you would on a RT at highway speed.

I don't listen to music except during ferry, and if talked on the cell phone thru the headset while my wheels were off the ground that would be a FCC violation. Couldn't have that now, could we? So really, idk how well the NC works when the airplane is working.

 

[36654]

You did say headset. My bad.

I am in an enclosed cockpit, so my ride is not as comparable. Two blade prop here, redlines at 2750 and is turning between 2500 and redline while I'm working. In a 'Cat or Weatherly you'd be sitting behind a R-985 or R-1340, probably also spinning a two blade at around 2700. But there you'd have no more "slipstream" effect than you would on a RT at highway speed.

I don't listen to music except during ferry, and if talked on the cell phone thru the headset while my wheels were off the ground that would be a FCC violation. Couldn't have that now, could we? So really, idk how well the NC works when the airplane is working.

With a two-blade prop turning at ~2700-rpm.........that wake interaction frequency would be ~90-hz, which is likely you most annoying noise. Corner and edge vortices (i.e., vortex shedding and frame response) at the window and frame joints are likely contributing at other frequencies. In both cases, these sources occur at relatively discreet frequencies which the adaptive circuitry can accommodate.

Interestingly, our annoyance level for these lower frequency sounds might actually increase with age due to the decay of our frequency range.