As Richard Cullen Rath explains, in early America the limits of the town were defined by being withing 'earshot' of the town's bells.  The sounds of particular bells also gave towns their own aural signature.  Bells also defined the time of day for all within range.

Sounding boards were used to concentrate and amplify the minister's voice chapels of early America.  Rath contrasts the architectural acoustics of colonial meeting houses with the medieval church, in which sound was characterized by reverberation and deconcentrated authority.   The sounding board directed and aplified sound, but those of higher rank in the front had best access to the minister's voice.  Those in the back, the poor, and slaves, had less access, proving their spiritual needs to be of less importance.

The stethescope allowed doctors to read patients more objectively.  The symptoms explained by the patients were no longer the only aural source for understanding the human body.  The need for touch was decreased by this device and allowed for more remote diagnoses.