Hello Michelangelo and all,
My final project is to put my raspy and volumio in my car, plugged in my hifi car system.
My question/request is: can Volunio turn raspy into a wifi access point? I mean, can I connect my smartphone directly to volumio webui avoiding the router?
Obviously everything in wireless mode… 
Thank you very much!
The title of this thread is kinda wrong… Volumio with AD-HOC or Volumio as AP would be better.
You want to use a Raspberry Pi with Volumio as a Access point or a so called hotspot or AD-HOC network, and not just without a router. You dont need a router to use volumio, it only needs some sort of connection that can handle http trafic.
Setting this up is possible, but (currently) not using the web-ui. This needs to be done using the command-line.
A quick google on debian accespoint or debian ad-hoc wireless gives plenty options on how to set this up.
It could be a nice feature for the web-ui in a future version, or an option that this is set by default for first installations when there is no wired network or serial etc. connection available.
+1 for this feature. It would be handy to configure device in this fashion in a routerless situation.