I have pretty the same problem. After iOS6 update airplay has been working on and off and after the iTunes 11 update it's not working at all anymore. No airplay connection even though airplay speaker is listed in iTunes. On my iPhone I don't even get the airplay symbol anymore.
I tried all kinds of things but so far nothing helped.
I have the same issue and can play to no AirPlay speakers in my house right now, though they are visible to iTunes.
I did find this workaround, though, that may work if you have other, older Macs in your house. As it turns out, I have an older Mac mini running OS X 10.5.8 and iTunes 10.6. I am able to share out my iTunes library from my new MacBook Air running OS X 10.7.5 and iTunes 11 to the old mini and then play whatever I want from that iTunes. Screen Sharing comes in very handy for this. The older version of iTunes seems to have no problem connecting up to the AirPlay speakers around my house.
Anyway, that's not a solution, and I have tried all the same things you did above. Additionally, I tried turning wifi off and on on my MBA that refuses to play to the AirPlay speakers. I did this because I noticed that the list of AirPlay speakers changes when the wifi connection drops and comes back. But that still didn't coax iTunes 11 to stream to AirPlay speakers.
Hope you or someone else might find this a helpful work-around till Apple fixes this for real.
I had the same problem after updating to iOS 6 and the new iTunes. I tried all kinds of stuff and nothing worked. And then I tried a simple thing, and that fixed everything for me. I signed out of everything. Out of my iPhone, iPad, iTunes, everywhere I could find a log in on my devices and iTunes, I did. I signed in again everywhere and bam, and it's all back to working just fine. I see my airplay speaker, I can select it and music gets piped through it and my iPhone works as a remote again.
I have exactley the same problem. However, get this I also have an Apple TV so in desperation I closed down iTunes on my Mac Mini switched on the apple TV went to air play and it found my speaker and started streaming from the Cloud to the speakers. No dropping coughing or spluttering just as it should be. Distance between Apple TV and speaker on a different floor.
Ergo the problem lies within iTunes. It cannot be the network as ATV is on the same wireless network.
Mac Mini Dec 2012, Mac Book Air, Mac Book Pro, 2 ipads, 2 iphones.
This issue is driving me nuts! I had orignally uninstalled itunes 11, but was forced to upgrade at ios7. The only Win PC (Win 7) in the house will not show up in home sharing or show Airplay when itunes 11 is open. Won't show Apple TV or Airport Express. I uninstalled Norton 360, reinstalled Bonjour, Checked setting in my Motorola Cable modem, Windows firewall....
BenOr, please try this post. https://discussions.apple.com/thread/3507281?start=0&tstart=0
Many people were able to resolve it by disabling IPV6 on their network adapter (s). My problem was that I have two wired network adapters on my desktop and I was using them in teaming mode. It was all working and then suddently one day it stopped. So recently I removed the teaming option and it started working for me.
Thanks VANresh -
After more time than I care to remember workign on this, it appears uninstalling Bonjour completely, then going to Apple and reintallign the newest version has fixed the issue. Multiple times now I have opened Itunes and the icon is there! I tried the repair feature and it did not work.