Speakers
These are one of the most common output devices used with computer systems. Some speakers are designed to work specifically with computers, while others can be hooked up to any type of sound system. Regardless of their design, the purpose of speakers is to produce audio output that can be heard by the listener.

These are transducers that convert electromagnetic waves into sound waves. It receive audio input from a device such as a computer or an audio receiver. This input may be either in analog or digital form. Analog speakers simply amplify the analog electromagnetic waves into sound waves. Since sound waves are produced in analog form, digital speakers must first convert the digital input to an analog signal, then generate the sound waves.

The sound produced by It is defined by frequency and amplitude. The frequency determines how high or low the pitch of the sound is. For example, a soprano singer’s voice produces high frequency sound waves, while a bass guitar or kick drum generates sounds in the low frequency range. It system’s ability to accurately reproduce sound frequencies is a good indicator of how clear the audio will be. Many include multiple speaker cones for different frequency ranges, which helps produce more accurate sounds for each range. Two-way speakers typically have a tweeter and a mid-range speaker, while three-way speakers have a tweeter, mid-range, and subwoofer.

Amplitude, or loudness, is determined by the change in air pressure created by the speakers’ sound waves. Therefore, when you crank up It, you are actually increasing the air pressure of the sound waves they produce. Since the signal produced by some audio sources is not very high (like a computer’s sound card), it may need to be amplified by it. Therefore, most external computer are amplified, meaning they use electricity to amplify the signal. Speakers that can amplify the sound input are often called active speakers. You can usually tell if a speaker is active if it has a volume control or can be plugged into an electrical outlet. Speakers that don’t have any internal amplification are called passive speakers. Since these speakers don’t amplify the audio signal, they require a high level of audio input, which may be produced by an audio amplifier.