I have been running Windows 10 on my HP Envy Ultrabook for the last 7 months and have always had choppy and very poor Audio that stuttered and cut in and out. Interestingly when using VLC the audio was fine but when using IE, Edge, Groove or Films & Movies apps the audio was so bad that the applications where not usable for audio.
This evening I have hit upon a fix to my poor audio problem, by changing the default sample rate in the advanced tab of the audio output device from 16bit 44100Hz to 24bit 192000Hz. Once I made this change youtube videos started playing correctly, Groove music was perfect and my Xbox Minecraft game even stopped crashing when loading!
To get to the default sample rate setting, right click on the speaker icon in the notification area, select playback devices, right click the playback device and select properties, click the advanced tab and increase the sample rate.
Now to see if tweaking my microphone settings will allow Cortana to hear me more clearly !