Hey everyone - this is Sam Beck, founder / designer at Blueshift.
Thanks for reading, and thanks for your comments. I would like to clarify some issues that have been raised - if you have more questions or would like to get in touch directly, feel free to email me personally - sam [@] blueshiftPDX [point] com.
1. Is this project actually open-source?
Yes. The power supply based on BQ24640 reference design that some of you have referred to is the key piece of this system - at this point, our working prototypes use the TI reference design plus a separate class D amplifier. The design will be integrated onto a single board, along with the Bluetooth module.
So, there is still work to be done - as it gets done it will be published under an appropriate license. It would be nice to have all that work completed in advance, but at some point a business has to find customers and confirm that there is demand for a product. My idea of how this business will work (expensive parts, direct-to-consumer sales) is not particularly conducive to finding investors, so we needed to raise money to finish development this way.
2. Is this product actually sustainable?
It is a step in the right direction. I don't mean to be tongue-in-cheek saying that - but it's a consumer product, if sustainability is the ONLY goal we should all just sing together.
What makes it sustainable:
Durability / longevity. I expect 20 years of life out of every part, including the supercapacitors - and all the parts can be replaced. At this point, my image of how that replacement will work in the real world is that the entire PCB can be replaced (in the event that it fails, that Bluetooth is replaced with a new standard, that a superior power source becomes available, etc). In terms of repairing individual components on the board, no specific plans have been made to make that easier, but it is a good point, and any input into how that should be achieved would be taken gladly. It is likely the capacitors will all deteriorate over time at a similar rate, and if they ever need to be replaced it will make sense to replace all of them at once.
Beyond that, I have chosen materials that I think make ethical sense. MDF is full of formaldehyde and I don't like having it in the shop. Bamboo is great acoustically, and I don't think there's an argument that it is a 'bad' choice - although if there is, someone should please make it!
If this product is going to make a real difference with respect to how sustainable our culture is, I think the biggest impact it could have is in encouraging others to think about alternative power sources, and more broadly to think about DIFFERENT WAYS TO DO STUFF. If everyone does the same thing just because it makes sense (e.g. lithium batteries), where will innovation come from?
3. Does it live up to 5 minute charge / 6 hours playback claim?
Yes. I can show you the math, but Serge is about right. Actually each 2.7V / 350 F capacitor stores about .35 W*h. So, the actual average power per channel at full blast is less than 200mW. It's the system efficiency that makes it loud - and Serge is also right, it's not insanely loud. But it is loud enough for most purposes, I've seen as many as 20-25 people dancing to it - people who were in no way compensated for their dancing I might add.
4. Does it live up to other grandiose claims generally?
Look, I designed and built this system, so maybe I'm biased - but I believe in it, and I am about as cynical as anyone.
The sound is good - natural, no DSP, and flat enough for my ear to about 100Hz. It charges in 4 minutes as currently configured, from the point at which it stops working (* not 0V) to a full charge.
DigitalTrends has a prototype right now, they'll be writing it up hopefully Wednesday next week and then we'll have an unbiased review of the actual system.
I hope that helps convince you all that this is a legitimate project in progress. The issues that you have all pointed out are the issues that any new hardware business - run by a first time entrepreneur, with a tiny budget - might have.
Again, please get in touch if you have questions, or if you feel any of what I've said is not in the spirit of open-source hardware. Thanks!