How can I understand Light as a Wave?

[ossumguywill]

@ossumguywill: remember that you can't destroy energy, no matter what you do

That's why I said it didn't make sense. :na:

The sound is locally cancelled not dissipated (in case of interference), but somewhere else amplified, you just divert the power. Practically all hearing protection is passive and dissipates the energy, but that's not interference.


What you are looking at is the field, and the power goes with the field squared, so that peak is 4 times as high in power than a single source, or double the power of the two sources combined. Average the 4 times higher peak with the periods of 0, and you end up with 2, the combined power of two sources.

This is what I assumed. It's just that in most explanations I hear, people make it sound as though the peak power is 2x the original peak power when it should be 4x.

Plugs.

If you have a few hundred lying around (which, judging by the fact that you are using a pair of elite analog earplugs, you do), you could get some Triple.Fi 10 IEMs reshelled to form-fit your ears based on a mold taken by your ENT, which would offer excellent sound proofing as well as excellent sound quality from a music player or device that balances out sounds like you described. Personally, I feel like I could easily go shooting with my standard non-reshelled Triple.Fi 10s, as with the included foam tips I can't hear anything with music playing.

Come to think of it, even the stock Triple.Fi 10s are rated at 26dB reduction versus the 25dB of those ESP plugs, and many say it is actually better with the foam tips. For under $200 on amazon, that's not all that bad of a deal...

 

[pullbangdead]

If you have a few hundred lying around (which, judging by the fact that you are using a pair of elite analog earplugs, you do), you could get some Triple.Fi 10 IEMs reshelled to form-fit your ears based on a mold taken by your ENT, which would offer excellent sound proofing as well as excellent sound quality from a music player or device that balances out sounds like you described. Personally, I feel like I could easily go shooting with my standard non-reshelled Triple.Fi 10s, as with the included foam tips I can't hear anything with music playing.

Come to think of it, even the stock Triple.Fi 10s are rated at 26dB reduction versus the 25dB of those ESP plugs, and many say it is actually better with the foam tips. For under $200 on amazon, that's not all that bad of a deal...

Ummmm.....ok.....I'm not sure what you're trying to say.

First, I know the guy that owns ESP, his name is Jack, real nice guy. And I am also friends with one who used to be one of biggest distributors. I like Jack, I like his company and how he does business, I trust him, and I LOVE his products in every way. I highly recommend them based on 5+ years of personal experience, including literally tens of thousands of rounds through my firearms, and I recommend them even at full retail price. That said, I admit that I didn't pay full retail price in the first place.

Next, are these things you suggest designed for shooting? I see the circuitry is rated as 26dB vs. 25dB, but the ESP shooting protection plugs don't JUST provide the 25 dB NRR noise reduction, they provide more protection than just that, such as the 90dB cutoff. Without the cutoff, the protection isn't adequate at all, 26dB off of 130+ isn't enough. I trust a product designed by a shooter AND an audiologist more than anything designed by an audiophile and an audiologist. And of course all of the ESP plugs are custom-fit from molds.

But enough of the derailment.

ETA: Wait a second, on the Amazon page, I see "changeable ear tips provide -26dB of isolation & passive noise cancellation". Passive noise cancellation only? This whole thread is about using ACTIVE cancellation of a wave through interference, and ESPs use ACTIVE noise cancellation. Those earplugs aren't even in the same class as real active noise cancellation, like on the ESPs. Sure, maybe they are isolating enough to use for shooting, but top suggest you could replace ESPs with them is silly, not even close to the same thing. And you can integrate a headphone plug into the ESP plugs if you like, as well. Of course it won't be audiophile quality music, for that get headphones instead of using your shooting earplugs.

But again, enough of the derailment. The ESPs were mentioned because they provide ACTIVE noise cancellation of a wave using interference. Let's continue discussing the interesting or confusing bits of wave theory.

 

[ossumguywill]

I'm not trying to say anything... just suggesting a different product. :beer: I'm not saying those things are bad... (although personally, I would rather have 26dB of passive isolation than 25dB of active isolation... passive isolation can never run out of batteries... :thinking By the way, I'm 99% sure that that 90dB cutoff rating is the cutoff rating of the speaker inside the device itself... If I detonated a 200dB firecracker next to your head, that little thing could never bring it down to 90dB. If you wanted, you could always turn down the volume on your iPod or other device below 90dB... LOL.

 

[pullbangdead]

I'm not trying to say anything... just suggesting a different product. :beer: I'm not saying those things are bad... (although personally, I would rather have 26dB of passive isolation than 25dB of active isolation... passive isolation can never run out of batteries... :thinking By the way, I'm 99% sure that that 90dB cutoff rating is the cutoff rating of the speaker inside the device itself... If I detonated a 200dB firecracker next to your head, that little thing could never bring it down to 90dB. If you wanted, you could always turn down the volume on your iPod or other device below 90dB... LOL.

The ESP is 25dB active + much MORE passive, I'd venture to guess the passive isolation alone is around 40dB (I don't honestly know what it is though). With the batteries out of my ESPs, the isolation is still better than foamie earplugs in my experience. With 25dB isolation only, a 130dB noise is still well over 100dB, which isn't healthy and isn'y enough for shooting. You're talking about something completely different, and you don't understand what you're talking about in reference to ESP earplugs. These products are not comparable, and your product doesn't have anything to do with this thread. And I CERTAINLY wouldn't take it shooting with me and trust it to protect my hearing. Listening to music, sure.

Seriously, you want to use your music headphones worth hundreds of dollars for shooting because they have 25dB of passive isolation and NOTHING else? You need to be using these foamies and leaving your headphones at home. The headphones give you ZERO advantage over these foamies, and in fact the foamies work better. Things like ESP provide ACTIVE, SELECTIVE noise canceling, even selective noise boosting, and are in a whole different ballpark.

Now please, wave interference.

 

[ossumguywill]

These products are not comparable, and your product doesn't have anything to do with this thread.

Right, because your shooting plugs have anything to do with a thread about light waves. Sorry for making a friendly recommendation about a related method...

 

[pullbangdead]

Right, because your shooting plugs have anything to do with a thread about light waves. Sorry for making a friendly recommendation about a related method...

indeed.

While we're here, how do noise-canceling headphones not violate the law of conservation of energy?

They're not allowed to, it's the law after all.

But if the sound interferes destructively where your ears are, it will interfere contructively somewhere else. Interference redistributes where the energy goes, it doesn't add or takes away energy.

Another nice problem: if you have two point sources like this:

You see an inteference pattern around. This also works when you have then oscillating out of phase, the pattern only changes slightly.
But when you bring them close to eachother, much closer than the wavelength, you have two source emitting in opposite phase at practically the same location, so there's destructive interference everywhere around. Now why is the light field suddenly gone? take any one of the sources away and there's light, but adding two sources out of phase close enough takes away the light everywhere.

It took my teacher a while to answer this one

So one's ears are always conveniently in the destructive area?

As long as the headphones are well-designed. Wouldn't be very useful to design noise-canceling headphones that amplify the noise, now would it? It's not a coincidence, it's part of the design.

My shooting earplugs are really cool like that though: they lessen loud noises and amplify quiet noises, bringing everything to the same volume. Very cool stuff, well engineered.

earplugs or full over ear headphone type earplugs?

Perhaps I should've written a bit more about the design/engineering aspect, and how it relates to the fact that you can create destructive or constructive interference, selectively, at your eardrum. Like the image in Bluefan's post, you can use the same 2 point sources and selectively choose where the constructive and destructive interference will take place by changing the phase of the second source. A very good illustration. I'm talking about a real-world application where such wave theory is actually used, and quite successfully at that.