Ever wanted to yell, "Will you please turn that *&^#@ thing down," at the neighbors? If only you had something that would actually show them how loud their TV/radio/stereo sounds on your side of the living room wall. Well, there are such instruments, and you can get them and use them to do just that.
Sound Level Meter
A sound level meter measures the loudness of sound at a particular moment and at a specific distance from the source of the sound -- the closer you are, the louder the sound. A hand-held unit contains both a microphone that picks up sound and converts it to an electrical signal and a meter that reads that signal in units called decibels. The range of sound an average person can hear is zero to 120 decibels. Normal conversation usually registers at about 60 decibels. If the meter goes to 120 decibels, you are either standing next to a jet engine or in the front row at a rock concert, and you're in serious pain.

Dosimeter
A noise dosimeter is somewhat like a radiation dosimeter. It measures how much sound a person is exposed to, and is normally used in an industrial setting to take readings during a work shift. A dosimeter system comes in two parts: a microphone clipped to a worker's clothing to register sound and a "reader" used after the testing period to quantify the recorded sounds and translate them into data.

Instrument Use
Both a sound level meter and a dosimeter are sensitive precision instruments and should be handled carefully. Keep them in their carrying cases when not in use. Protect them from water and dust. Don't drop them or throw them around. Don't try to disassemble them or clean them -- leave this to a professional. Read the instructions that come with them, and follow these carefully.

Availability
Sound-measuring instruments can be purchased from an electronics store or rented from companies that provide this service.