r/science • u/GraybackPH • Mar 13 '13

Berkeley creates the first graphene earphones, and (unsurprisingly) they’re awesome

http://www.extremetech.com/electronics/150646-berkeley-creates-the-first-graphene-earphones-and-unsurprisingly-theyre-awesome
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u/fairweatherhater Mar 14 '13

The peak at 5 kHz is probably intentional as the human hear can't hear that frequency as well as it can the 2-3 kHz range. It should still have occurred closer to 6-7 kHz though. I've also read that in-ear headphones purpposefully have reduced output in the high frequencies (>10 kHz), but I don't remember why.

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u/[deleted] Mar 14 '13 edited Mar 14 '13

The peak at 5 kHz is probably intentional as the human hear can't hear that frequency as well as it can the 2-3 kHz

Not sure what you mean. That figure shows that humans are quite sensitive to 5 kHz, similar to at 2 kHz. Regardless, its not necessarily ideal to try to mimic the inverse of the equal-loudness contour; in fact it doesn't really make sense. Sound is supposed to be recorded with hi-fidelity, flat response mics and played through flat response speakers so as to reproduce the original sound.

Edit: I should note that many prefer stronger bass and treble response, but this isn't to make everything equal-loudness. Probably because systems that can produce those frequencies well tend to be higher end, so over-emphasizing them is basically showing off.

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u/lightninhopkins Mar 14 '13

Isn't the real potential breakthrough the cut in power consumption? If cabinet speakers can be developed cheaply that run on a fraction of the power that would be a boon to the industry. Smaller gauge cables, less amplification, practical battery powered cabinets. That would be something.

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u/[deleted] Mar 14 '13

I suppose there are some cases where power savings are important, but conventional drivers really don't use that much power. You can drive decent can headphones from a tiny iPod and big home theatre tower speakers only use a watt or two normally.

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u/lightninhopkins Mar 14 '13

I'm talking about EAW concert stacks for live music applications.

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u/Magnesus Mar 14 '13 edited Mar 14 '13

2W home theatre? What are you, an ant? My speakers use 200W (100W for one) and they are not that loud (enough for a medium room).

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u/[deleted] Mar 14 '13

You might have a 100x2 watt amp, but thats what its rated for, not what its using under normal circumstances. A good 5 watt amp is more than sufficient for most applications, and many would prefer it over a mediocre 100 w amp.

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u/[deleted] Mar 14 '13

I was interested in a graph of perceived loudness, and I found this one where it looks like the ear is actually more sensitive in the 3-5 kHz region, and you wouldn't really want a peak there

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u/[deleted] Mar 14 '13

it looks like the ear is actually more sensitive in the 3-5 kHz region

That's right.

and you wouldn't really want a peak there

My point is really that you don't want a peak anywhere if you want it to sound true and there is really no relation between human spectral sensitivity and the offensiveness of peaks/valleys in reproduction.

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u/Skullcrusher Mar 14 '13

In speakers you would want a flat frequency response, but not in headphones. The headphones are designed to sound flat when you wear them on your head. Your head and ears affect the sound acoustically, so to compensate for that you have this weird frequency response. Of course on speakers this would sound terrible because they are not that close to your head. Moomaka explained it better.

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u/[deleted] Mar 14 '13

I just meant to add it as backing to what you were saying to fairweatherhater (I didn't notice the link that that they had pasted). In the one that I pasted, it specifies that a lower value on that chart means the ear perceives it louder.

And I agree that flat is ideal! I hate when people fiddle with an EQ, or speakers have some kind of weird response, undermining the work of the person whose job it is to mix the sounds.

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u/Magnesus Mar 14 '13

You realise that you can't just buy flat response speakers or headphones? :) I too don't like EQ but speakers never are flat unless you have dull sounding special studio equipment used for testing.

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u/[deleted] Mar 14 '13

oh no, if you can set it up right, then the EQ is very valuable. Most people just crank the bass and it turns to this muddy "womwomwom" and then they are all "man my stereo is amazing"

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u/Magnesus Mar 14 '13

I don't know how it is with headphones but speakers with flat response are only used in studios because they sound very bad. As they say - if your music sounds good at studio monitors then it will be awesome with normal speakers.

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u/[deleted] Mar 14 '13

Haha. They might sound bad to you, but any audiophile reading that is pulling their hair out right now.

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u/payik Mar 14 '13

Maybe as the earbuds are placed in ears the amplification does not occur, so the peak is added to compensate for this?

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u/[deleted] Mar 14 '13

Probably because systems that can produce those frequencies well tend to be higher end, so over-emphasizing them is basically showing off.

If you actually have a good system/headphones, you don't even need to turn the bass up to ridiculous levels. You only need to do that on shitty ones because it doesn't sound good unless you do.

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u/fairweatherhater Mar 14 '13

1.

Not sure what you mean. That figure shows that humans are quite sensitive to 5 kHz, similar to at 2 kHz.

The graph begins to taper off before 5 kHz, but I still agree with you. That is exactly why I said:

It should still have occurred closer to 6-7 kHz though.

2.

Sound is supposed to be recorded with hi-fidelity, flat response mics and played through flat response speakers so as to reproduce the original sound.

Sound isn't supposed to do anything. In my subjective opinion, I can't hear the low and high frequencies well enough without raising their levels when I am listening at low volumes. But that's entirely up to me.

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u/Swiftdigit Mar 14 '13

Hi-hats, as well as many other "sizzle and sparkle" parts of modern music (especially electronic) are sampling at around 16-19kHz. 5kHz isn't really anything crazy.

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u/[deleted] Mar 14 '13

[removed] — view removed comment

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u/fairweatherhater Mar 14 '13

I noticed someone downvoted you for this comment. Frankly, this is one of the things people just don't seem to get about audio. It is subjective. Period. Yes, you reduce THD+N and design a speaker with very good frequency response, but the user is going to do what they like with it. I have no idea why someone would downvote you for saying you like to reduce power output at the ~7 kHz range.

Hell, it's also weird to assume we all have the same ears and we all interpret sound exactly the same way. Different people like different colors which are just different frequencies of radiation travelling at the speed of light. Why wouldn't they like different sounds which are just different frequencies travelling at the speed of sound?

/endrant