Audio output sounds great in some apps — and lousy in others, especially whit spoken-word playback
Two things you need to know about the the speakers on the Nexus 5: First, there's only one speaker. Never mind that you see a pair of speaker grilles — there's only one speaker hidden back there. As we first learned on the LG G2 — a close cousin, insofar as the hardware goes — there's a speaker, and there's a microphone. Not two speakers. That's been confirmed by iFixit's teardown, as well, not that it was a surprise. Stick your finger over one of the speakers and it's readily apparent.
There other thing we've discovered is that the Nexus 5 speaker can be pretty decent, or it can be downright horrible — and it appears that software may be to blame here.