what is a Microphone stand

A microphone stand is a free-standing mount for a microphone. It allows the microphone to be positioned in the studio, on stage or on location without requiring a person to hold it.
 
The most basic microphone stand is called a "straight stand". It uses a dome-shaped round metal base into which is threaded a post for mounting the microphone. This post may be made up of two or more telescoping tubes that fit inside each other, allowing for quick, one-handed height adjustment of the stand. The mechanism for adjusting the height is called the clutch.
 
There are various versions of the straight stand known as the "desk stand" (short version of straight stand) and heavy duty microphone stand (heavier base and larger tubes) to handle heavy microphones. The tubes used on the straight stand usually have a shiny chrome plating to resist scratching, but may also be finished in a matte black.
 
A very popular updated version of the straight stand uses the "folding tripod base stand", instead of the round, domed metal base. This folding base allows for easier packing of the stand when moving from location to location and reduces the weight of the stand. However, to compensate for the lack of weight at the base while still maintaining stability, the three "feet" of the tripod must extend out beyond the radius of a round base. The trade-off is that these "feet" may become a trip-hazard on a dark stage.
 
There are a number of accessories that make microphone stands more useful. Most of these are designed for getting the microphone closer to the user without placing the upright portion of the stand directly in front of the performer.
 
A "boom arm" can be attached to the top of the stand in order to allow the placement of the microphone to be moved in the horizontal plane. This might, for example, allow a guitar player to place the microphone directly in front of his mouth without having the upright portion of the stand in the way of the guitar. It also allows the microphone to be placed closer to the sound source when floor space is at a premium. This can be particularly useful when placing microphones on a drum stand when the microphone stands must compete for space with things like cymbal stands. Boom arms are offered both in fixed length and adjustable (telescoping) lengths.
 
Another handy device for adjusting microphone placement is a flexible "goose neck" tube. Made of a spiral-wound core of steel, goosenecks are made in various lengths and finishes and provide the ability to make minute changes in microphone position.
 
Microphones are attached using a detachable microphone holder screwed to the end of the boom. (Some microphones screw directly onto the boom.) The commonly used screw threads are:
 ⅝″ 27 threads per inch (tpi) Unified Straight thread (UNS, U.S. and the rest of the world)
 ¼″ BSW (uncommon in the U.S., used in the rest of the world)
 ⅜″ BSW (uncommon in the U.S., used in the rest of the world)