Noise means any unwanted sound. Sounds, particularly loud ones, that disturb people or make it difficult to hear wanted sounds, are noise. For example, conversations of other people may be called noise by people not involved in any of them; any unwanted sound such as domesticated dogs barking, neighbours playing loud music, portable mechanical saws, road traffic sounds, or a distant aircraft in quiet countryside, is called noise.
In English private law defines a nuisance as "an unlawful interference with a person's use or enjoyment of land or of some right over, or in connection, with it." The process of determining what level of noise constitutes a nuisance can be quite subjective. For instance, the level of noise, its length and timing may be taken into consideration in ascertaining whether a nuisance has actually occurred.
Many jurisdictions have laws defining loud music as a criminal offense, typically a misdemeanor.[citation needed] The exact definition of what constitutes a loud music violation varies by location, either at a certain volume (measured in decibels) or the distance from the source at which the music can be heard. The time of day is also often a factor in the law, with the restrictions in some places applying only to specified nighttime hours (e.g. 11 PM-7 AM). The amount of effort put forth by law enforcement members in dealing with loud music also varies by location. The most common punishment for a conviction is a fine or some other small sanction. But on rare occasions, loud music may be grounds for imprisonment. In May 2008, a United Kingdom woman was sentenced to 90 days in jail for violating a court order not to play music that disturbed her neighbors eleven times.
Police have also at times discovered other crimes, such as illegal drug usage, when investigating loud music complaints. Many public transportation services have rules against the use of sound-producing devices without earphones, or even with earphones if the music can be heard by others. [citation needed] Since mass transit agencies are frequently government-operated and or subsidized, these rules can be legally enforced, and violation may result in prosecution. In 2014, Michael Dunn got a conviction after he got into a fight with several young adults over their loud music. After his arrest, he said, "I got attacked and I fought back because I didn’t want to be a victim and now I'm in trouble.