Graphene used for speaker prototype
- Thread starter Jeff Babcock
- Start date
Re: Graphene used for speaker prototype
I wonder what the resistance of the graphene is? Usually the resistance of an electrostatic diaphragm needs to be somewhere in the range of tens of megohms.
And I wonder if this will scale up to full-size electrostatic panels?
I wonder what the resistance of the graphene is? Usually the resistance of an electrostatic diaphragm needs to be somewhere in the range of tens of megohms.
And I wonder if this will scale up to full-size electrostatic panels?
Re: Graphene used for speaker prototype
It appears to have a figure-eight pattern. Is it possible to array multiple figure eights to produce unidirectional coverage? Would it work with one side of the diaphragm blocked?
Chris
It appears to have a figure-eight pattern. Is it possible to array multiple figure eights to produce unidirectional coverage? Would it work with one side of the diaphragm blocked?
Chris
New speaker tech.. *Graphene*
http://www.extremetech.com/electroni...theyre-awesome
[h=3]Share This article[/h]
Researchers at the University of California, Berkeley have created the first ever graphene audio speaker: an earphone. In its raw state, without any kind of optimization, the researchers show that graphene’s superior physical and electrical properties allow for an earphone with frequency response comparable to or better than a pair of commercial Sennheiser earphones.
A loudspeaker (or earphone or headphone) works by vibrating a (usually) paper diaphragm (aka a cone), creating pressure waves in the air around you. Depending on the frequency of these waves, different sounds are created. Human ears, depending on their age, can usually hear frequencies between 20Hz (very low pitch) and 20KHz (very high). Generally, the quality of a speaker is defined by how flat its frequency response is — in other words, whether it produces sounds equally well, no matter where they fall on the 20Hz to 20KHz scale. A poor speaker, or, say, a bassy set of headphones, might be very strong in the lower ranges, but weaker at the top. (See: In search of the perfect headphones.)
In Berkeley’s graphene earphone, the diaphragm is made from a 30nm-thick, 7mm-wide sheet of graphene. This diaphragm is then sandwiched between two silicon electrodes, which are coated with silicon dioxide to prevent any shorting if the diaphragm is driven too hard. By applying power to the electrodes, an electrostatic force is created, which causes the graphene diaphragm to vibrate, creating sound. By oscillating the electricity, different sounds are created.
Graphene earphone frequency response (top), vs. Sennheiser MX-400 earphones (bottom)
Given graphene’s status as a wonder material we shouldn’t really be surprised, but it turns out that this graphene speaker — the first of its kind — has intrinsically excellent performance. As you can see in the graph above, the graphene earphone’s frequency response is superb. The reason for this is down to the graphene diaphragm’s simplicity: Whereas most diaphragms/cones must be damped (padded, restricted) to prevent undesirable frequency responses, the graphene diaphragm requires no damping. This is because graphene is so strong that the diaphragm can be incredibly thin — and thus very light. Instead of being artificially damped, the graphene diaphragm is damped by air itself. As a corollary, the lack of damping means that the graphene diaphragm is also very energy efficient — which could be important for reducing the power usage of smartphone and tablet speakers.
Remember, we are talking about a completely untuned, unoptimized earphone, and yet its frequency response is superior to a magnetic coil speaker that has been the target of decades of research and development. If that wasn’t exciting enough, the researchers say that their method of growing graphene with chemical vapor deposition can easily be scaled to produce larger diaphragms and thus larger speakers. In all likelihood, following some more research, graphene will go on to become the material of choice for studio speakers — and hopefully, cost permitting, consumer speakers and earphones as well.
http://www.extremetech.com/electroni...theyre-awesome
47
inShare
inShare
Researchers at the University of California, Berkeley have created the first ever graphene audio speaker: an earphone. In its raw state, without any kind of optimization, the researchers show that graphene’s superior physical and electrical properties allow for an earphone with frequency response comparable to or better than a pair of commercial Sennheiser earphones.
A loudspeaker (or earphone or headphone) works by vibrating a (usually) paper diaphragm (aka a cone), creating pressure waves in the air around you. Depending on the frequency of these waves, different sounds are created. Human ears, depending on their age, can usually hear frequencies between 20Hz (very low pitch) and 20KHz (very high). Generally, the quality of a speaker is defined by how flat its frequency response is — in other words, whether it produces sounds equally well, no matter where they fall on the 20Hz to 20KHz scale. A poor speaker, or, say, a bassy set of headphones, might be very strong in the lower ranges, but weaker at the top. (See: In search of the perfect headphones.)
In Berkeley’s graphene earphone, the diaphragm is made from a 30nm-thick, 7mm-wide sheet of graphene. This diaphragm is then sandwiched between two silicon electrodes, which are coated with silicon dioxide to prevent any shorting if the diaphragm is driven too hard. By applying power to the electrodes, an electrostatic force is created, which causes the graphene diaphragm to vibrate, creating sound. By oscillating the electricity, different sounds are created.
Graphene earphone frequency response (top), vs. Sennheiser MX-400 earphones (bottom)Given graphene’s status as a wonder material we shouldn’t really be surprised, but it turns out that this graphene speaker — the first of its kind — has intrinsically excellent performance. As you can see in the graph above, the graphene earphone’s frequency response is superb. The reason for this is down to the graphene diaphragm’s simplicity: Whereas most diaphragms/cones must be damped (padded, restricted) to prevent undesirable frequency responses, the graphene diaphragm requires no damping. This is because graphene is so strong that the diaphragm can be incredibly thin — and thus very light. Instead of being artificially damped, the graphene diaphragm is damped by air itself. As a corollary, the lack of damping means that the graphene diaphragm is also very energy efficient — which could be important for reducing the power usage of smartphone and tablet speakers.
Remember, we are talking about a completely untuned, unoptimized earphone, and yet its frequency response is superior to a magnetic coil speaker that has been the target of decades of research and development. If that wasn’t exciting enough, the researchers say that their method of growing graphene with chemical vapor deposition can easily be scaled to produce larger diaphragms and thus larger speakers. In all likelihood, following some more research, graphene will go on to become the material of choice for studio speakers — and hopefully, cost permitting, consumer speakers and earphones as well.
Re: New speaker tech.. *Graphene*
40 dB down at 30 Hz and 15 K from 200 Hz, the graphene earphone’s frequency response is superb.
Yeah, right.
40 dB down at 30 Hz and 15 K from 200 Hz, the graphene earphone’s frequency response is superb.
Yeah, right.
Re: New speaker tech.. *Graphene*
I'm kind of surprised at those Sennheiser phones as well, makes me wonder where and how they got that measurement. Regardless, that graph looks pretty bad even with 40dB of range crammed into the space I would normally expect to see 6dB. That wouldn't even fit on the screen in my normal measurements.
I'm kind of surprised at those Sennheiser phones as well, makes me wonder where and how they got that measurement. Regardless, that graph looks pretty bad even with 40dB of range crammed into the space I would normally expect to see 6dB. That wouldn't even fit on the screen in my normal measurements.
Re: Graphene used for speaker prototype
Conventional cone drivers also have a figure-8 pattern. For that matter so would a compression driver diaphragm, so probably conventional compression driver or cabinet designs would be used.
Conventional cone drivers also have a figure-8 pattern. For that matter so would a compression driver diaphragm, so probably conventional compression driver or cabinet designs would be used.
Re: Graphene used for speaker prototype
Not surprising to hear hyperbolic claims, don't buy any stock just yet. :-(
JR
[edit- perhaps written by same crew that wrote about the graphene super cap... /edit]
Not surprising to hear hyperbolic claims, don't buy any stock just yet. :-(
JR
[edit- perhaps written by same crew that wrote about the graphene super cap... /edit]
Last edited:
Re: New speaker tech.. *Graphene*
There is a huge difference between a proof-of-concept prototype and a developed and finished product. It would have been good to have less smoothing (presumably) on the curve to get an better idea about the inherent qualities of the concept though.
There is a huge difference between a proof-of-concept prototype and a developed and finished product. It would have been good to have less smoothing (presumably) on the curve to get an better idea about the inherent qualities of the concept though.
Re: New speaker tech.. *Graphene*
I have no idea how they can claim that the graphene is "comparable to or better than" the Sennheisers.
According to that graph, the Senn's are within 10dB of their peak level between approx 90Hz and 7k5Hz.
Not great by professional standards, but for an £8.99 pair of consumer units, I guess that's to be expected.
The graphene only manages to stay within 10dB of peak between approx 70Hz and 600Hz - that is at least a decade narrower useable bandwidth.
Their claim just doesn't bear any resemblance to the graphs at all.
Researchers at the University of California, Berkeley have created the first ever graphene audio speaker: an earphone. In its raw state, without any kind of optimization, the researchers show that graphene’s superior physical and electrical properties allow for an earphone with frequency response comparable to or better than a pair of commercial Sennheiser earphones.
I have no idea how they can claim that the graphene is "comparable to or better than" the Sennheisers.
According to that graph, the Senn's are within 10dB of their peak level between approx 90Hz and 7k5Hz.
Not great by professional standards, but for an £8.99 pair of consumer units, I guess that's to be expected.
The graphene only manages to stay within 10dB of peak between approx 70Hz and 600Hz - that is at least a decade narrower useable bandwidth.
Their claim just doesn't bear any resemblance to the graphs at all.
Re: New speaker tech.. *Graphene*
Headphone measurement requires special apparatus, and even then there's some controversy still about what shape the response should be, with a given apparatus, to "sound flat" when the phones are used by a human. Were any details given about the method for taking the measurements?
Headphone measurement requires special apparatus, and even then there's some controversy still about what shape the response should be, with a given apparatus, to "sound flat" when the phones are used by a human. Were any details given about the method for taking the measurements?
Re: New speaker tech.. *Graphene*
Maybe we need a Graphene thread. Looks like things will get quieter as they get louder.
Improving electronics by solving nearly century-old problem
Maybe we need a Graphene thread. Looks like things will get quieter as they get louder.
Improving electronics by solving nearly century-old problem
Re: New speaker tech.. *Graphene*
More graphene magic as a salt water filter/purifier.
Perforene: A Graphene Water Filter 100 Times More Efficient
More graphene magic as a salt water filter/purifier.
Perforene: A Graphene Water Filter 100 Times More Efficient
Re: New speaker tech.. *Graphene*
yes, there are many amazing uses for this stuff coming out. We could stick to sound and electronics and make something that looks like the Behringer thread. If we include all the other stuff, look out. Bennett will need a new server. Everyday I search something new about it and I'm never disappointed.
Hype, maybe. Or it could be just what we needed and just in the nick of time.
I want to patent the idea of using different size Graphene filters to scrub smoke and ash as a way of reclaiming elements and then distilling the gasses left over but I don't have time so I simply claim any similar patent to be void because of prior published art (this sentence) and therefore part of the public domain.
~:-D~:grin:
yes, there are many amazing uses for this stuff coming out. We could stick to sound and electronics and make something that looks like the Behringer thread. If we include all the other stuff, look out. Bennett will need a new server. Everyday I search something new about it and I'm never disappointed.
Hype, maybe. Or it could be just what we needed and just in the nick of time.
I want to patent the idea of using different size Graphene filters to scrub smoke and ash as a way of reclaiming elements and then distilling the gasses left over but I don't have time so I simply claim any similar patent to be void because of prior published art (this sentence) and therefore part of the public domain.
~:-D~:grin:
Re: New speaker tech.. *Graphene*
Don't worry, Mark, thanks to the help of Phil Graham and Jeff Knorr, Dave and I (and by extension all of you) are sitting pretty. The forum traffic would have to quadruple for us to start seeing problems. vBulletin may be a beast, but it is easy to tame with some clever caching and optimization. Can you believe we run this thing on less than a gig of RAM?
Don't worry, Mark, thanks to the help of Phil Graham and Jeff Knorr, Dave and I (and by extension all of you) are sitting pretty. The forum traffic would have to quadruple for us to start seeing problems. vBulletin may be a beast, but it is easy to tame with some clever caching and optimization. Can you believe we run this thing on less than a gig of RAM?
Re: New speaker tech.. *Graphene*
My first real computer (heathkit version of DEC LSI 11/2) could only address 28k x 16b ram fully loaded.
I probably couldn't host much of a website on that.
JR
My first real computer (heathkit version of DEC LSI 11/2) could only address 28k x 16b ram fully loaded.
I probably couldn't host much of a website on that.
JR
Re: New speaker tech.. *Graphene*
Along the same lines as molecule size based filtering, I wonder if a stiff material, maybe graphene, could be made to produce sound without moving air? If the material is completely permeable for most of the molecules in air, and still dense enough to bounce a vast majority of the molecules, could one create the waves without having to use up a lot of energy moving air back and forth?
Along the same lines as molecule size based filtering, I wonder if a stiff material, maybe graphene, could be made to produce sound without moving air? If the material is completely permeable for most of the molecules in air, and still dense enough to bounce a vast majority of the molecules, could one create the waves without having to use up a lot of energy moving air back and forth?
Re: New speaker tech.. *Graphene*
Sound is air moving back and forth...
For linear materials advancement it is an issue of mass to rigidity, for advanced new technology think of alternate ways to move air (like local heating, or ionized, or whatever).
JR
Sound is air moving back and forth...
For linear materials advancement it is an issue of mass to rigidity, for advanced new technology think of alternate ways to move air (like local heating, or ionized, or whatever).
JR
Re: New speaker tech.. *Graphene*
Ok, this one is cool
Graphene: Aviation's Deicing Revolution? - AviationPros.com
Ok, this one is cool
Graphene: Aviation's Deicing Revolution? - AviationPros.com