There is a rubber layer, coated with conducting material to serve as electrodes. The signal is applied in form of a high voltage which makes the electrodes attract each other and contract the rubber in between perpendicular to the surface (i.e. the rubber layer gets thinner). Since the rubber material is relatively incompressible though (volume of the material doesn't change), the surface area of the membrane has to increase in return. To generate sound from that, the membrane is stretched over a cavity that is under higher than ambient pressure which helps expand the 'balloon' when its surface area increases. This displaces surrounding air which means the contraption is emitting soundwaves.
(I could only find a thumbnail of the first page of a paper from that professor and extracted this from it)
This sounds like an "electroactive polymer." there are some squishy tapes made by 3m that incidentally have this property out of the box. Make a spot of conductive carbon paint on each side, apply a few kV, and watch the spots double in area as the electrostatic forces squish the material.
> Current loudspeakers use a magnet coupled with the movement of a copper coil to vibrate a membrane.
In the future these heavy, bulky, and expensive components could be replaced by a dielectric elastomer membrane.
They mention efficiency, but not power. I don't like how this is framed as the general future of all speakers when it's really just the future of midrange drivers.
Heavy speakers is a plus when moving low frequencies. Otherwise you have to strap or bolt them down and together.
_Might_ be the future of mids, but I doubt it. Advancement in ribbon speakers is more likely
IMHO.
Also people develop a taste for how some speakers sound. I don't see guitar music being played on anything too different for a while, unless it has the same sound character. Even if technically it's a better reproduction, it has to reproduce how paper cone speakers sound now better than paper does. Seems unlikely. To win, people have to like the new sound more, or not be able to tell the difference.
Considering how many people listen to music through phone speakers or laptop speakers or portable mono speakers I think consumer tolerance is far higher than you're guessing. Many homes these days don't have any speakers aside from the ones that came with the TV and if you want higher quality you reach for the earbuds or headphones. The vast majority of people aren't audiophiles.
> Heavy speakers is a plus when moving low frequencies. Otherwise you have to strap or bolt them down and together.
I get it.
But I would rather have that in two parts. It is not always needed, in that there is a place to put the speakers, and I could leave the heavy stuff at home
I have a pair of 35 year old Mission speakers constructed using rubber and so far there's no evidence of degradation and they still sound great.
I imagine if this was a tyre then it wouldn't fare so well because the rubber compound is for a completely different use and also exposed to adversities such as wide temperature differences and all sorts of kinetics that a speaker will never experience (hopefully).
I've done it! A relative of mine had two Gallien-Krueger 250ML guitar amplifiers, which are an interesting bit of kit, but the 5" speakers had foam surrounds that rotted out. I ordered and installed generic replacements from Parts Express. For my part, I was just curious about how the amps would sound.
As for the Bose, they were nothing special as speakers, and I already had a stereo that I was happy with, so I disposed of them.
I bought (separately, used) a full set of older Infinity surround speakers. Eventually they all had to be re-foamed, but I managed to do it myself with parts ordered online. Have some acetone on hand to take the glue back off if you get it wrong and have to try again...
This was about 10 years ago but here in New Zealand I found someone who could repair and replace the rubber so my 30 year old infinities are as good as new.
Speaker surrounds are replaced when necessary. For several decades foam was used, and it tended to break down. The butyl rubber usually used now lasts thirty to fifty years when not exposed directly to sunlight.
Why would I want to replace the headphones I am using for a decade with something I have to replace every few years. Its already sad enough that I have to replace my phone every year or two because of its battery and software upgrades that slow it down.
You can now add headphones to your upgrade cycles because number of new phones with reasonable specs and wired headphone support are becoming rare.
If this proves cost effective to manufacture and resulting headphones come with inbuilt obsolescence due to batteries and degrading rubber, we'll see manufacturers aggressively pushing this new technology.
Well I guess it's not the wooden box of a speaker that costs $2000-$30000 (normal price range for consumer Hi-Fi speakers). Replacing the speaker drivers would be more like replacing everything within the body of a car.
Justification isn't really a thing in that market (see also: luxury watches).
My friends who are into hi-fi/audiophile stuff who value accuracy typically do go for studio monitors or similar (e.g. Harbeth) vs. stuff like Wilson Audio. Some of them still buy fairly woo-woo stuff like spendy cables even though they might know better, but at least they don't go in for the pure scam stuff like Shakti Stones or directional Ethernet cables...
I genuinely wonder the same actually. Seems like there would go even more engineering into making a speaker that is "true" and not coloring the sound as one expects from their monitors.
There's plenty of real engineering but it's only engineers that can differentiate the heavily marketed and absurdly marked up snake oil things from what's real. DIY people share honestly good designs that are underperformed by speakers/amps that cost 10x or more.
You're right that it's about a space, or a field, which is in the name, but you're wrong in contradicting the other poster. The near field is determined by the radiating surface, the front baffle of the speaker. Room height line arrays for example have a large near field. Near field speakers are those with tuning designed to be flattest when listened to inside the near field. The link you posted is confused and misleading, which is unfortunate since they dressed it up as some kind of "myth busting".
It's easy to trick people into overspending on audio gear because you can use their love for music and their subjective biases and their egos against them. It's like the perfect situation for slimy sales tactics.
Beware, if you're spending $10k+ on consumer hifi speakers you're almost definitely getting ripped off.
It costs only a few thousand at most to get the raw parts and materials to build truly world class speakers (quality-wise) that are loud enough for any normal living space. Maybe not for a concert hall type space, but that's not consumer hifi anymore.
I find it a bit strange that this article doesn’t mention electrostatic speakers, as the two appear similar.
It would also be worth mentioning if this new tech suffers from the same limitation as electrostatics, namely that the membrane’s range of motion is so small that you need several square meters of membrane to reproduce low frequencies at high volume.
It doesn't. This scheme uses a membrane like the electrostatic speakers, but otherwise it is quite different. In the electrostatic speakers, you load the membrane with extra electrons and then use electro-magnets to apply a varying electric field across the membrane in accordance with your sound signal. Since the membrane has much more electrons than protons, the electric field causes the membrane to move. This method requires magnets.
The system in the article does not use magnets. What they do is they make a membrane that moves when a voltage is applied between its top and bottom surfaces. Thus, the membrane can probably be referred to as being piezoelectric, although the article does not use that term. In this case you can apply the sound signal directly to the membrane and make it move, and when it moves it creates sound. Thus, this system does not require any magnets.
The lack of magnets will make it much lighter. Also, the fact that you are applying the signal directly to the thing making the sound may result in better sound quality.
You are correct. They do not use magnets but grids of stators. These grids of stators apply a good old fashioned electric field not a magnetic field. But the main difference remains, you still need two latge heavy things that take the sound signal and actually move the membrane.
Like an electrostatic speaker the opposite charges' attraction generate movement. The difference is in an ESL one of the charges are stationary. In this new scheme, both charges are on the membrane but on opposite sides where attraction compresses/thins the rubber causing it to expand along its planar directions causing the dome to get larger. The inner air pressure is to assist the expansion movement.
As I understand it, the rubber being is forced into the shape of a dome via air pressure, which makes one side a bit bigger than the other. The electrostatic charge on the opposing faces when one is bigger than the other would cause it to flex - acting as a speaker diaphragm.
It's a bit of a guess though; its definitely outside my wheelhouse.
This is the response of someone who knows that electrostatic speakers are a thing and has seen marketing or other images of them, but has no idea how they work and lacks either the curiosity or the capability to learn. The speakers described in this article are nothing close to electrostatic speakers.
This meets the criteria of Poe's law. It is equally reasonable to assume _you_ are being sarcastic or serious. If they didn't just recently look up the definition themselves, they wouldn't have commented about the conflict in the two definitions.
The commenter specifically used the word nonplussed in reference to the ranking of this post on the front page. The fact that their surprise and confusion stems from the promotion of unimpressive stories does not change the meaning from surprised and confused to unimpressed.
Well its certainaly not a non negative statement because its talking about being plussed, which is a positive statement, so a nonplussed person is truly chaotic-neutral.
I was wondering much the same, except I note that my pal’s massive Quads and the older radiator-like versions at uni were still crazy heavy due to the power supply (I assume) and they were a bit short on warm bass, perhaps these “new” speakers run on a trickle of power and produce bass like a Cerwin-Vega for all I know?
The power supply problem is not power but voltage, electrostatic speakers just require high voltage
Also they are expensive audiophile thing so good chance they were driven off some super inefficient and/or made on discrete componentes, hence the size
My screen readers reads that site in a verry strange way. It says that there is soft hyfens in a lot of the words so it reads the words like reproduce as"repro duce"
It looks like they are doing some sort of dynamic text justification. If I change the text width by resizing the window it dynamically inserts hyphens at line breaks. Presumably via some javascript library.
The article mentions the fragility, but seems extremely optimistic on the ability to solve this, but I'm not sure way. It just says "once this is overcome" but the things it seems to be talking about are major barriers to a commercial product.
It was just the other day I was thinking how big, comparatively speaking the speaker components are in MacBook and iPhone. And if we could somehow make it even smaller without any compromise on quality and longevity.
Yes, as we know from the history of electrostatic speakers, all you need to replace those bulky magnets is a sheet of mylar the size of a billboard, and also a regular magnetic voice coil for the half of the power spectrum that they can't handle.
And with lower frequency sound, aren't heavy drivers actually better? You literally need more mass/energy to push more air, but at a lot lower frequency so the effect of moving the mass back and forth at 20Hz does not really matter as much as 40Khz?
The weight of the driver is not really a factor so much as a side effect of the engineering. You want to look at it in terms of total volume displaced and the sensitivity (if you are thinking about efficiency). Drivers with more surface area & excursion typically do have larger magnets and support structures.
LFE reproduction is all about moving large volumes of air by any means necessary. There are relatively featherweight subwoofers that literally use fans to move volumes of air and achieve performance that is impossible in traditional drivers of any weight class.
Doesn't really matter how you do it as long as things stay in phase.
> There are relatively featherweight subwoofers that literally use fans to move volumes of air and achieve performance that is impossible in traditional drivers of any weight class.
Wow I've never heard of this, what are these called? Would love to read more about this tech
Just to +1 this, in general nobody wants to read AI textspam anywhere. I hope the trend is over now but like a month ago any time somebody would ask a question on the slack I'm on, someone else would copy-paste 500 words of chatgpt blathering with a similar "disclaimer".
We all know about chatgpt now. If someone wants a chatgpt answer to their questions, they can go get that themselves.
I verified that the textspam was indeed correct, and I thought it would be an interesting factoid for HN, as 99.9% of people are only familiar with dynamic driver.
> Repeat after me: chatgpt is not deterministic
Brilliant insight, and definitely a better addition to the thread than somebody trying to add details that presumably only an audiophile would know.
There is a rubber layer, coated with conducting material to serve as electrodes. The signal is applied in form of a high voltage which makes the electrodes attract each other and contract the rubber in between perpendicular to the surface (i.e. the rubber layer gets thinner). Since the rubber material is relatively incompressible though (volume of the material doesn't change), the surface area of the membrane has to increase in return. To generate sound from that, the membrane is stretched over a cavity that is under higher than ambient pressure which helps expand the 'balloon' when its surface area increases. This displaces surrounding air which means the contraption is emitting soundwaves.
(I could only find a thumbnail of the first page of a paper from that professor and extracted this from it)
https://www.aes.org/e-lib/browse.cfm?elib=21108