[HN Gopher] Classic components could be replaced by rubber in ne...
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Classic components could be replaced by rubber in next-gen
loudspeakers
Author : crousto
Score : 73 points
Date : 2023-06-03 18:18 UTC (4 hours ago)
(HTM) web link (www.polytechnique-insights.com)
(TXT) w3m dump (www.polytechnique-insights.com)
| _Microft wrote:
| These speakers seem to work like this:
|
| 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
| yummypaint wrote:
| 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.
| sandreas wrote:
| If you want an affordable, good sounding speaker that you can
| build yourself, you might wanna take a look at Tech Ingredients:
|
| https://www.youtube.com/watch?v=CKIye4RZ-5k
| Kapura wrote:
| 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.
| smnscu wrote:
| [flagged]
| KennyBlanken wrote:
| > I had ChatGPT expand on the paragraphs
|
| Yeah, don't do that. Nobody wants to read "AI" textspam here in
| the comments.
|
| > so take the audiophile considerations with a grain of salt
| lol.
|
| The understatement of the year. Repeat after me: chatgpt is not
| deterministic.
| kennywinker wrote:
| 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.
| dsr_ wrote:
| This appears to be describing an electrostatic speaker. They're
| on the market, and have been for decades, using mylar or a
| similar material.
| vr46 wrote:
| 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?
| ilyt wrote:
| 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
| hristov wrote:
| 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.
| buildbot wrote:
| Yeah I am really nonplussed how this is the top post on HN
| right now (I know that is against the rules to mention but
| really)
| ahahahahah wrote:
| 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.
| coldtea wrote:
| Because it has nothing to do with EL speakers -- this is just
| the casual HN dismissal
| TulliusCicero wrote:
| > Yeah I am really nonplussed
|
| Well this tells me nothing.
|
| (The two meanings of this word are essentially opposite)
| CrampusDestrus wrote:
| The wrong meaning is the opposite of the right meaning
| samstave wrote:
| > _Well this tells me nothing._
|
| 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.
| falcolas wrote:
| I can't tell if serious or sarcastic. Either way, here you
| go.
|
| nonplussed : adjective
|
| - Bewildered; unsure how to respond or act.
|
| - Unfazed, unaffected, or unimpressed.
|
| - filled with bewilderment
| flyingcircus3 wrote:
| 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.
| flyingcircus3 wrote:
| Summarizing dictionary.com:
|
| 1. Surprised and confused 2. Unperturbed
|
| "Yeah I am really unperturbed" doesn't make sense in
| context of it's parent.
|
| I'm not sure how you could be nonplussed about this.
| coldtea wrote:
| > _" Yeah I am really unperturbed" doesn't make sense in
| context of it's parent_
|
| It's not just unpertrubed, it's also "not impressed".
|
| In the context of the comment it basically means "I see
| this speaker announcement as nothing special, what's the
| big deal?".
| dist-epoch wrote:
| I'm not so sure. Electrostatic speakers have big heavy metal
| electrodes.
|
| They talk about a thin conducting layer on the rubber, quite a
| different thing.
| aidos wrote:
| They definitely look very different. I understand how ESLs
| work, but I don't quite get how these move. Can anyone
| explain?
| falcolas wrote:
| 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.
| karmakaze wrote:
| 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.
| chrisdhoover wrote:
| Magnepan speakers have been around since the 1970s. They do
| not have anything heavy. Martin Logan speakers do have a
| heavy base presumably the driver.
| jakedata wrote:
| Don't confuse magneplanar speakers with electrostatic
| speakers. Other than them both being flat they are quite
| different beasts.
| buildbot wrote:
| This seems only mildly different than already existing
| electrostatic drivers??? In terms of getting rid of heavy magnets
| at least.
| jeffbee wrote:
| 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.
| buildbot wrote:
| These seen smaller than a billboard: https://www.crutchfield.
| com/S-Me16Db11xTX/p_839EMESLD/Martin...
|
| 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?
| bob1029 wrote:
| 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.
| ilyt wrote:
| > These seen smaller than a billboard: https://www.crutchfi
| eld.com/S-Me16Db11xTX/p_839EMESLD/Martin...
|
| Right... because this one contains a normal magnetic woofer
| Puts wrote:
| Wouldn't rubber dry out over time? If you pay for a good set of
| speakers you probably want them to last for decades.
| coldtea wrote:
| Couldn't you just replace it? We also pay for good cars, but we
| still change their tires every so often...
| sublinear wrote:
| > 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.
| tapper wrote:
| 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"
| gtvwill wrote:
| Ehhhh interesting, might go well for tweeters. Can't see it being
| great for bass. Can't be arranged in a paraflex horn config.
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(page generated 2023-06-03 23:00 UTC)