The phrase "audible groan" means a sound of frustration or disappointment that can be heard by others.
Sentences with «audible groan»
Of course, these plans get you 3G service with AT&T — the mention of which drew audible groans from those in attendance at Apple's event. (macworld.com)
When we took communion their were audible groans and some people even spit it out. (nakedpastor.com)
The question on tax brought an audible groan from the journalists. (politics.co.uk)