What would room temperature superconductivity do for audio?

[kemmler3D]

You might have seen the recent claim that room temperature superconductivity has been achieved. It's probably bogus this time, but it's not out of the question that it would happen someday, so - what if?

https://www.iflscience.com/first-ro...uperconductor-achieved-claim-scientists-70001

I'm not personally savvy enough about the intersection of physics, speaker driver design, and electronics to day what might use these materials might have in audio, but presumably there's something there.

What if you used superconducting wire for the voice coil, for example?

Could we build more powerful amps in smaller boxes?

Would the final veil be lifted if you used superconducting speaker cables?

Does anyone with a more suitable background care to speculate more concretely how sound reproduction might benefit if you could have superconducting parts in whatever part of the system you wanted?

 

[Keith_W]

Well, I was going to say "lift veils" and "wife can hear it in the kitchen" but you beat me to it

It would probably allow us to manufacture tiny voice coils which have more powerful magnetism than what we have currently. Also more linear transformers. Amplifiers that don't waste as much energy as heat.

But it is also important to remember that superconductivity loses its superconductive properties above a certain temperature, so if your voice coil / electronics / etc. heat up, or the ambient temperature is too high, it will lose superconductivity, resistance will skyrocket, and your equipment will fail to work. So I would imagine some kind of active cooling would be required to maintain it at an operating temperature. It will have to be a superconductor at higher than room temperatures for it to work reliably for us average consumers.

 

[nerdstrike]

Expensive. It's not easy to maintain 100 gigapascals!

I could see it allowing heavier cones for better distortion characteristics, or perhaps really mighty ribbon speakers.

 

[antcollinet]

You could have hair thin very long speaker cables. You could just run them by sticking them to the walls with your normal paint, or behind paper for invisible speaker connections wherever you wanted.

 

[antcollinet]

Amplifiers that don't waste as much energy as heat.

That would require superconducting semiconductors giving on state superconductivity - which is a whole other ball game. Plus would only work for class D

 

[alex-z]

Increased damping factor due to no resistive losses in the cables. Higher performance DAC's and amps, as more of the PCB can be used for shielding instead of power traces.

But you will probably never see superconductors in a consumer application. It isn't enough to be superconducting at room temperature, it is retain that property over a 40-60 degree temperature range, and simultaneously not be susceptible to the collapse of the Meissner effect when external magnetic fields are introduced.

 

[kemmler3D]

Well, I was going to say "lift veils" and "wife can hear it in the kitchen" but you beat me to it

It would probably allow us to manufacture tiny voice coils which have more powerful magnetism than what we have currently. Also more linear transformers. Amplifiers that don't waste as much energy as heat.

But it is also important to remember that superconductivity loses its superconductive properties above a certain temperature, so if your voice coil / electronics / etc. heat up, or the ambient temperature is too high, it will lose superconductivity, resistance will skyrocket, and your equipment will fail to work. So I would imagine some kind of active cooling would be required to maintain it at an operating temperature. It will have to be a superconductor at higher than room temperatures for it to work reliably for us average consumers.

For the sake of this discussion I guess let's just assume the recent (probably bogus) report is real. It works up to about 250F at 1ATM. So it pretty much just works?

I could see it allowing heavier cones for better distortion characteristics, or perhaps really mighty ribbon speakers.

Ribbons or maybe planar magnetics might be interesting.

I assume that normal Ohm's Law calculations don't work with superconductive materials because R=0? But presumably you could have extremely high currents and therefore very strong magnetic fields compared to today, which I guess would make any transducer perform better, no?

 

[DVDdoug]

Conservation of energy still holds.

I'm not sure what it would be good for... Switching power supplies and class-D amplifiers are already in the ballpark of 90% efficient. Class A or Class A/B amplifiers won't work without variable resistance in the semiconductors, so a superconducting MOSFET would only be useful in a Class-D amp. Almost no energy is lost in cables.

I'm not sure what it does for speakers (or other "motors"). Speakers are very inefficient but lower impedance doesn't automatically increase efficiency (with normal copper or aluminum voice coils). The physics might change with superconductors, but I don't know...

P.S.
And, I only get excited when something becomes economical.

 

[LTig]

For the sake of this discussion I guess let's just assume the recent (probably bogus) report is real. It works up to about 250F at 1ATM. So it pretty much just works?

Ribbons or maybe planar magnetics might be interesting.

I assume that normal Ohm's Law calculations don't work with superconductive materials because R=0? But presumably you could have extremely high currents and therefore very strong magnetic fields compared to today, which I guess would make any transducer perform better, no?

Of course Ohms law works but you have to set R=0. However AFAIK superconducting in practice is limited by the factor current/area. For a given area (diameter of the wire if it's circular) the current must stay below the limit, otherwise the superconducting effect breaks down and the wire becomes resistant. If this happens bad things may result, like the instanteneous destruction of the wire by it heating up due to the amount of power it has to dissipate which it was never designed to handle.

 

[Soria Moria]

Not really on topic for this thread, but I'm super excited about what it can do for games.
There doesn't seem to be much exciting left to wait for in audio (that a room temperature superconductor could make happen).

 

[Cbdb2]

You could replace driver magnets with superconducting field coils that would weigh almost nothing, produce extremely large magnetic fields and run off almost no power. Also very low mass voice coils. Maybe one or two other things it might help (dynamic mics long speaker runs) , but I can't see an advantage for audio electronics.

 

[Cbdb2]

This would involve a major shift in speaker/amp design. The speakers impedance would be almost zero at some frequencies so the amps would have to be current sources. The crossovers would also have to be resistance free so superconducting inductors.

 

[voodooless]

I’d be a bit careful with that paper. The same people got busted for faking data on a previous claim of room temperature superconductivity.

 

[pablolie]

The truth is we don't quite know. We haven't played around with superconductivity in practical applications, and in fact several things still seem contradictory in lab experiments. We do however know that superconductivity and magnetism fight each other, which would be a challenge for audio designs.

 

[Cbdb2]

But magnets are one of the big reasons to go superconductive.

Nothings free.

 

[DonH56]

I've actually played with (low-temperature) superconductors in the past, including some at least quasi-practical uses (data converters, logic circuits, microwave/mmwave filters in aircraft large enough to handle the cooling requirements), but take that paper with a block of salt. It would be an incredible breakthrough if true.

 

[mhardy6647]

I imagine superconducting materials would increase the price of consumer hifi appreciably.
In other words -- they'll be coming soon.

 

[Muddywaters]

Very cool

 

[pablolie]

I imagine superconducting materials would increase the price of consumer hifi appreciably.
In other words -- they'll be coming soon.

*If* it happens at room temperature with a conductor that is not made out of $$$$ unobtanium, it wouldn't have to be so from a bill of materials point of view - but you're probably right and they'd find a way to justify a big whopping price tag - nothing is new under the sun. :-D

 

[kemmler3D]

This would involve a major shift in speaker/amp design. The speakers impedance would be almost zero at some frequencies so the amps would have to be current sources. The crossovers would also have to be resistance free so superconducting inductors.

Sounds like the first superconducting speakers (if we ever get such a thing) would probably be best designed as DSP actives so we could keep the electronics simple. But it's interesting to think about what might be possible with stronger magnetic fields and super-low MMS. Presumably current / magnet-related distortion would disappear...