It's amazing to me how quiet everyone can be when they're trying not to wake the baby.

Also amazing:
- Doorbells ringing
- Dogs barking
- Monkeys crying
- Phones ringing
- Toilets flushing
etc. etc.

Don't take this as a suggestion not to call -- by telephone or in person. I don't think any of those sounds has ever startled the baby, even a full-on bark at the terrible intrusion of the USPS letter carrier.

It's just a matter of perception, like shouting into a stethoscope or looking at the sun.