My personal experience is that the buitl-in speakers are not very good at all -- they would be fine for video conferencing, but suck for audio. What I was surprised by though is the headphone response -- bass is extremely limited (and I know these haedphones well, they reproduce bass fine) I would be vey surprised if these have anything approaching a "flat to 20Hz" response. Otherwise, quite listenable, just anemic in bass.

YMMV, all my subjective opinion. I have the equipment to measure the response, but doubt I will bother - would love an EQ though...