I think you need to learn how to use a tape measure properly.
A Play One might seem small in the adverts you've seen, but if you look at the actual dimensions rather than guessing what you think the size is then the truth is revealed. The Play 3 and Play 5 are quite a bit larger in real life than they appear on web ads too.
Whether a Play One fills a living room with sound depends on how large your living room is and how much sound you want. As Scotty said "
Ya cannae change the Laws of Physics ". The Play One isn't a humongous stack system, but it is quite potent. I have customers all over the North West using them in kitchens, conservatories, living rooms, bedrooms and they're very happy with the sound. The Play 3 is a definite step up though. The Play 3 to Play 5 jump isn't so pronounced.
Your idea of a CA amp (Topaz AM1 / AM5) + speakers, while valid, isn't quite the giant killer you'd like to believe. Have you had a look at the amp specs? I mean from the user manual and not just the headline wattage figure from the RS or CA site. Do you know how much real world power both of those amps put out? The answer is 10W per channel in to 8 Ohms. Even then it's not clear if the measurement is continuous power or if they've just measured one channel to make the figures look flattering.
The AM10 has got a bit more about it. However it's spec is even more vague. "80% of the rated power" - what's all that about? Why not just write 28W; what's the need for the smoke and mirrors? Once again there's no indication if this is continuous power or whether they're driving a single channel.
You might get the impression I have a downer on Cambridge Audio. I don't. The company makes some superb gear. It's a simple fact that people buy on specs they don't really understand, and most of their decisions are based on nothing more in-depth than "
this number is bigger than that number ". Before the days of
everything-on-the-internet catalogue-style shopping for Hi-Fi these sort of spec' issues weren't really a problem. You'd have a chat with a dealer and they'd guide you through the products and show first hand why product X was better than product Y. They knew which products worked well together and why. You'd hear the difference that a better amp or more efficient speakers would make. As a result people made far better and much more informed choices when buying proper Hi-Fidelity stereo gear. There are still dealers doing that, but not with £80 amps and £40 speakers. That just doesn't pay the bills.
Now it's an arms race to have the most Watts per £ sterling and so the way things are measured has slipped back and started to get very murky. We've not gone back to the days of P.M.P.O and the stupid figures quoted for old stack systems and boom boxes, but there's definitely a lot of very misleading info out there.
It's the same story of dodgy specs with the little T-Class amps on Ebay. They post a big number as the headline wattage figure, but in real world tests you're lucky to get 6-8 Watts out of the sub £100 variants before they run in to serious distortion. You'll get even less from the sub £50 ones. Since it's distortion that kills speaker rather than too much power, there's always a risk that driving an underpowered amp will do some damage sooner or later.
You plan to use one of these amps with some equally budget speakers. I'm afraid there's more bad news on the way then.
The same cost cutting goes on with them too. Have you noticed how many budget speakers are now 6 Ohm impedance rather than 8 Ohm? Have you any idea why they do that and what it means for the amp that has to supply the power?
Sonos isn't perfect by any stretch of the imagination. If all you want is a bunch of speakers with Wi-Fi then there are plenty of other solutions on the market including Chromecast Audio you mention. They all play music from the net and some from a NAS drive. Sonos does this too and has done since it was launched. The difference with Sonos is that you don't need a specific NAS drive or a fancy one that can run a server app. They designed it to work with even the most basic NAS drives.
What sets Sonos apart is it's extremely broad support for online streaming service, and the way a Sonos ecosystem works as a multi-zone music system. You have to play with a system to really start to appreciate just how sorted it is. You see, when you're a newbie you think you know what you want, and it looks like there are lots of products out there that tick all your boxes. However, once you've lived with a system for a few weeks you start to realise that what you thought you wanted isn't really what you need and value. The longer you live with it the more you come to appreciate that Sonos knew what you'd need all along.
Lots of companies have had a go at stealing the Sonos crown. Some of them have huge resources at their disposal. None have succeeded.
I'm not saying Sonos is perfect. It isn't. Right now the company has updated its control app and ****ed off a load of users in the process. They'll fix it, but in the mean time there's a few users who have fallen out of love with their systems. But it's only a speed bump in what has otherwise been a remarkably smooth road as far as the customers are concerned.
