Brass instruments are instruments that are played by the musician blowing into a tub in order to make a sound. The vibration of the lips as the player blows into the instrument is what really makes the sound. The valves on these instruments are opened and closed by using the keys pressed by the player's fingers and these valves are what allow the musician to alter the sound that is being made. The length of the tube is what also has an affect on the pitch.

While most brass instruments are in fact made out of brass, there are a few exceptions to the rule as some believe that an instrument should be classed as a brass instrument by the sound they make. Exceptions that are not made out of brass include the serpent and the alphorn. It is often mistaken that the saxophones are members of the brass family, but they are more correctly classed as a woodwind instrument.

There are four different types of brass instruments and they are classed into instruments that are known as natural brass instruments, keyed or fingered brass instruments, valved brass and cylindrical bore brass instruments, slide brass instruments and the conical bore brass instruments. Natural brass instruments are instruments that are limited in what notes they can play, such as the bugle and the trumpet.

Keyed or fingered brass instruments are brass instruments that are played by covering the holes in the body with the pads of the fingers, or the holes are covered by pads that are activated by the musician pressing the keys. Valved brass instruments have between three and seven valves that are operated by the musician's fingers. Examples of vavled brass instruments include the horn and the tuba. Cylindrical bore instruments are brass instruments that are a tube, like the others, but the diameter of the tubing does not change. Examples of the cylindrical bore include the trumpet and the trombone. Slide brass instruments are played with a slide, such as the trombone. Lastly the conical bore instruments are instruments that have the diameter of the tube increase. The French horn is a perfect example of a conical bore instrument.

Over time, many brass instruments have become obsolete and are not often used today. Many of the older and simpler brass instruments are the ones that have become obsolete, but the newer and more complex brass instruments continue to be played today. Brass instruments are best known for their bold tones and are often used in music to add power to the overall sound. Some have a rich sound while others can have more of a sharp sound that cuts through. Many of these instruments are not considered to be incredibly difficult to learn and are quite popular in schools who teach music to younger children. This is not to say that lots of practice is not needed and that these instruments are easy. Being able to control the air a person puts into the instrument requires a lot of practice.