Megaphone

From Wikipedia, the free encyclopedia

(Redirected from Bullhorn)
Jump to: navigation, search
For the pro-Israel lobbying software tool, see Megaphone desktop tool.
An electronic megaphone.
An electronic megaphone.
Unplugged jazzband's vocalist using a megaphone
Unplugged jazzband's vocalist using a megaphone
A megaphone, with a three-inch lighter to scale.
A megaphone, with a three-inch lighter to scale.

A megaphone, speaking-trumpet, bullhorn or loud hailer is a portable, usually hand-held, funnel-shaped device whose application is to send a person’s natural voice toward a targeted direction for a specified purpose. This is accomplished by channeling the sound through a funnel, which also serves to match the impedance of the voice cords to the air. The natural human voice tends to spread evenly in all directions, whereas when it is sent through a megaphone, the sound is concentrated in a given direction and the coupling of its energy to the air optimised.[1] The trade-off is that if a listener is to the side, it is more difficult to hear what is being said. An electronic megaphone amplifies sound to a higher decibel level. It consists of a microphone, an amplifier and a loudspeaker.

Inventor Thomas Edison exhibited an early version of the megaphone at the Paris Exposition.[citation needed]

Common uses for megaphones are at sporting events, political functions and generally when one needs to address congregations of people in open spaces. Police officers often use them to communicate with suspects and rescue crews during operations to communicate with the victim.

Another lesser known use is as vocal distortion by musicians. For example, Tom Waits is know for useing a megaphone in a variety of songs. The megaphone gives off a kind of gritty, untamed effect valued by many musicians.

  1. ^ See Example 1 of Impedance Matching for description of amplification mechanism


Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.