Sonos gets beaten up because it lacks a battery-powered product. Well known for its focus and a conservative product line-up, Sonos requires you to take a plugged-in extension cord wherever you want to enjoy the system – such as on your deck or by your back-yard pool. My own experiments with battery-powering a PLAY:1 give insight on why Sonos is stubborn, besides just their determined desire to own the domestic space (rather than audio in the car, or on the beach for that matter).
Sonos lives and dies by its network, and Sonos products turn into lumps when off the network (except for the Soundbar, arguably). While I could see a future where a farther-away (across a large yard) Sonos unit is synced via a cell connection, I doubt that’s happening soon. But also as a person who has lugged a PLAY:5 to my outside deck for a cookout, I had to explain to guests why I also needed that AC power extension cord. The PLAY:5 even has a nice handle integrated with its tuning ports, and it sounds pretty good outside.
For my experiment I tried the lower power PLAY:1 which also sounds good outside, near the house and its Sonos network. I have no desire to take the PLAY:1 to the beach. My goal was to see if battery-powering the system was practical and sounds good. The quick summary is that there are issues with both.
For the test I used the PowerBank Elite 25 from Nature Power which sells in the low $200 range. This power pack is about the size of a medium sized hardback novel and weighs about the same. The product’s primary purpose is to recharge phones/tablets through its three USB jacks, or to recharge a computer through its 120VAC plug. (I’ve used the unit to charge my laptop computer this way, and it works well.) To keep its cost down, the product is designed to create a simulated sine wave, meaning a choppy stair-step version of the nice smooth undulating sine wave you learned about in math class. The result is that this “unclean” power tends to cause noise in audio products, and can even damage some types of products. The PLAY:1 is well behaved, function-wise, but is not immune to this noise – a low-level midrange-frequency buzz that would annoy you in a quiet room. Use the system outside, playing music, and the buzz is generally masked.
(Clearly if Sonos made their own battery-powered product, they would not use my convoluted DC-to-AC-to-DC set-up… they would design the circuits to run straight from the battery, for far better efficiency.)
Speaking of Efficiency
I learned some interesting traits of the PLAY:1 through my testing. Sonos rates the standby power as 4 watts, meaning that the 93.2 watt-hour PowerBank will run the unit in standby only for about 24 hours before it goes dark – and you haven’t even played any music. So clearly you want to unplug this set-up until you are ready to use it, to avoid battery drain. Sonos doesn’t rate the normal running power of the system, but based on run-down tests with the battery, I estimate the core PLAY:1 system consumes about 10 watts, even when playing quiet music. In fact for levels up to about 75 dB (at 1 meter), the system only uses about 10 watts, so that 93.2 Wh battery gives 9 hours playing time. Bump the sound level to 85 dB (getting fairly loud for a single PLAY:1), the system consumes enough to shorten life to 7 hours. Go to 95 dB and you get 2 hours.
So this brings to light the real reason a battery powered Sonos is a challenging product to make. First, the baseline running power, for the network circuits, audio circuits, buttons, and lights, is pretty high. Second, to give the product its bad-ass performance (good bass, good dynamics, especially for a small system) they gave it a powerful amp, far larger than is ever seen in small battery-powered systems. Surely Sonos will someday have a battery-powered product, probably with great performance, though some combination of efficient transducer design and efficient power supply / power amp design.
Would you buy this product?
I’ve wondered whether – despite the power consumption – people would pay for a PLAY:1 battery-pack carry-bag as an accessory product. As a product designer, I’ve even researched the cost of making such a product, with the proper clean sine wave for good sound. It’s not cheap (take note of the battery cost I mentioned above.) I am curious, how much would YOU pay to carry your $200 PLAY:1 out to the deck or pool, without attached wires, within range of your Sonos network? Comment on this article, or email me, and maybe (just maybe) I’ll make you a product!
© 2014 Stephen Shenefield