It probably draws a large current. Power consumption is a hallmark of high-end audio equipment.

My Leaf also draws a large current when I stomp on the gas; but I got it with the premium audio package and it rocks.

Seems like it would make more sense to just buy a higher-end inverter for an off-grid solar setup; and charge the batteries when he's not using it.

Your leaf cost $30k, the article quotes $10k, and your own inverter/charger+battery setup is going to be at least several thousand.

Maybe buying, housing, and maintaining a bunch of electrical equipment awkwardly in your home isn't worth the difference to many.

Big ass -48vdc battery banks, float charge controllers and precision sine wave inverters are a solved problem. If it's good enough for a $235,000 Infinera DWDM platform...

Floor space is severely limited in Japanese homes however. I'm not an expert but what you describe sounds large. Most have a little bit of space at least on one side of the house however due to Japanese building code, so your own pole might actually be more practical ;-).

The funny thing is, all audio circuits run on DC power, thus necessitating the inclusion of an AC/DC converter in every piece of hifi equipment on the planet.

So if you go to the trouble of setting up a battery bank, it would make sense (both financial and sound quality) to ditch the sine wave inverter and hack your equipment to accept DC directly.

Take a look at this amplifier: http://www.allegrosound.com/Accuphase_P-400.jpg

Those giant round things and square things along the sides? Totally unnecessary if you already have a (DC) battery bank...

You know what's interesting to me? Almost everything runs on DC these days. Lights are solid state, just about all electronics have a power supply that converts to DC, even a lot of (admittedly high end) home gadgets use brushless DC motors. The only AC devices I can count in a normal home are the big appliances like electric stoves, HVAC fans, etc. I wonder why there has not been more progress in a DC home distribution standard. Especially because efficiency generally increases with load, all of those little wall warts are less efficient than one big AC to DC converter.

DC propagates very poorly. Not sure that matters in the few meters of a house though. But its the reason the house service is AC to begin with.

because there's no single DC voltage that all devices use, so you'd end up with homes wired with 48VDC and many power brick/wall-wart dc-dc converters to obtain 24VDC, 19VDC, 17.5VDC, 12VDC, 5VDC, etc.

and the cable gauge would need to be incredibly thick to avoid significant losses, DC does not go very far distances well at all. Be ready to pay for #2 gauge copper in your walls instead of 14ga.

All of that is also going to be expensive.

Like that ever stopped audiophiles and their $850 ceramic cable supports to hold up their $13,000 cables...