A handful of sounds from an unreleased Windows 10 Technical Preview build have popped up at WP7Forum, where they were spotted by The Verge. There are eight sounds in total, covering things like Calendar alerts, incoming emails, low battery warnings, and system messages. You can hear them all together in this YouTube video:
The Verge likens the new tones to the boot sound from Windows 95, but that doesn't seem exactly right. The Windows 95 sound invoked analog instruments such as vibraphones, strings, and a grand piano. And while the jingle had a certain dreamy quality, it also conveyed excitement. (And let's not forget that Windows 95 seemed even more excited when you shut it down.)
That's not the case with the new sounds. Composed entirely of reverberating, electronic keys, the tone here is mellow, even more so than the modern sounds of Windows 8.
It's possible that Microsoft will come out with different sounds when Windows 10 actually launches this summer, or that the sounds we haven't heard yet are more aggressive. But if even the critical low battery warning is just a splash of soothing synthetic vibes, chances are the entire system is going to sound pretty chill.
Why this matters: Ideally, the sounds of an operating system aren't something you should have to think about too often. Nobody likes a computer that yells, though, and the opportunities for Windows 10 to do so will be greater with the inclusion of a full-blown notification center. By choosing a set of relaxing tones, it seems Microsoft is playing it extra-safe.