How to set up an apple network to stream music without having to leave a mac on

Question

I have two macbooks and a sonos system on a wireless network with a netgear router and timecapsule for back-ups. Now, I need to leave a macbook on for sonos to reach the itunes library. But the library is getting too big for the macbook, and Sonos will play better if the library is wired to the router instead of connected wirelessly like it is now, and I don't want to have to put on the macbook every time I want to play music.
So, do I put my library on the Time Capsule? Can it act like a NAS? And if so, I'd need to buy a second Time Capsule to back-up the music library, though I'm wondering if this second time capsule can back-up the first one?
Or should I just get a NAS to connect to the router, store the music there, and if so will my time capsule be able to back-up the library on the NAS? Does the NAS need to be ablt to support Time Machine in OSX?
Is this the way to go in trying to set up Sonos to play without having to turn on a macbook? Or any other suggestions?
Thanks for your help!

Answer 1

I will jump in and answer the part i know about.. but I do not use SONOS and don't even use itunes in a significant way.. so you will need to look deeper for other parts of your solution.
itunes is strange because it is not a server design.. this makes sharing it hard.. and that is deliberate due to copyright. Apple do not want you to simply copy your itunes for other people to use. So the library is linked closely to the player.
Moving the library has specific method. Apple documents gives you the method.
Of course this is really messy running a computer when you want to play music in lots of settings.. so a NAS is a better solution. TC is not a NAS.. it is a backup target for TM.
I (plus many experts here) do not think TC a suitable location for itunes library.
It has the following issues.. it is designed to be slow to spin up and fast to spin down.. Your computer will lose track of the library every time you boot or wake your computer. Streaming is difficult because the TC will tend to spin down the disk at the first opportunity.
2. It is easy to corrupt the library. Due to wireless connections many people use.
3. The TC cannot back itself up .. nor can TM backup network drives.
4. If the TC dies.. as they have a tendency to do.. your library is lost.. so backup is a serious problem.
Now the above does not stop people from doing it.. with varying degrees of success. never discount the backup problem. If you want to try remember this is not going to be straight forward.
A proper NAS has advantage of being able to back itself up.. it can also have spin settings fine tuned and higher speeds available as well as onboard data protection via raid.
But NAS is still not able to be backed up by TM nor is TM always reliable if backing up to it.. Apple made one and one only network target for TM .. the TC.
Your problem is far from unique.. a few seconds in google will give you loads of info.. even from the sonos forum.
eg http://forums.sonos.com/showthread.php?t=33468
Is this the way to go in trying to set up Sonos to play without having to turn on a macbook? Or any other suggestions?
Until Apple recognise the hole in their product lineup.. which is maybe deliberate.
A mac mini as a media computer/server (except itunes is not a server.). but you can build a quasi one. It doesn't need to be the latest .. a cheap second hand one say since 2010 should be more than powerful enough to do this role. Attach a large external drive.. not USB2 if possible.. that might mean fw800 or deliberately paying the extra for Thunderbolt mini and connections.