A great Mac feature in OS X Mountain Lion (and later versions) - is system-wide audio streaming over AirPlay. This Mac feature has been available on iOS devices for a quite a while through iOS Control Center.
With Mountain Lion (and later versions) - you can AirPlay directly from all applications on your Mac to your Libratone AirPlay speaker.
In System Preferences choose Sound and Output - and select your Libratone speaker for sound output. All sound from your Mac will now be sent directly to your Libratone speaker. Music, YouTube etc.
Please note that AirPlaying to multiple speakers simultaneously still requires iTunes or a 3rd party audio grabber application like AirFoil.
AirPlay for video sound (movies) can suffer from sync issue between video and sound. This relates to AirPlay and not to Libratone. All AirPlay speakers on the market will experience the same issue. For video sound - AirFoil Video Player from Rogue Amoeba or use a mini jack cable between computer and speaker.
AirPlay YouTube sync issues can be reduced significantly with YouTube5 Safari Extension for Mac.