It ocurred to me that it might not be perfectly clear, exactly what 30 dB sounds like. In fact, a year ago, I wouldn't have had a great idea what 30 dB sounded like either. Check out the speech banana:
Normal breathing is at 10 dB. Leaves rustling in leaves is 20 dB. Whispering is at about 20 dB also. Spoken language occurs mostly between 40 and 60 dB. We haven't really gotten into what frequencies he hears more easily yet (although generally, it's the lower frequencies). But, in terms of loudness, Lucas can hear us speak!