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How the Stereo Makes Sound Pleasant

The normal human being naturally has two ears. When it comes to sound, both ears would receive sound. For high fidelity sounds that we do subscribe to nowadays, we would require two sound sources to be able to have the most natural sounds through our ears. This is the stereo. Most of our gadget today have the stereo system where two speaker outputs are included for each device. In the world today, people, particularly the younger generation, like to listen to music. This has been made even much more interesting and possible through the advancement in technology and introduction of the stereo sound system. This paper, therefore, aims to illustrate how the stereo has made sound more pleasant to listen to.

Any stereo output system is made up of speakers as the sound output. The speaker works with the basic principle of electromagnetic induction. The basic design of a speaker is made up of; horn diaphragm, coil, magnets assembled together by two plates and a pole piece. A former; held by the pole piece, which is a heat resistant plate that allows for making the coil using thin copper wires. The thin copper coil, upon induction of alternating current (AC), a magnetic field is induced and hence and electromagnet is created. The coil movement up and down, due to the AC, is what makes sound wave production. the coil former is attached to the diaphragm. The diaphragm, through movement of the voice coil, displaces air particles around the membrane and creates sound waveforms. The diaphragm is suspended and connected to the voice coil using the spider. The coil is covered by a dust cap which prevents dust from getting in the speaker (Marty).

Depending of the nature of use of a speaker, different sizes, types and even number come into play. This entails either increasing or decreasing the sizes of the electromagnets, number of coils and even type of diaphragm material.  Upon movement of the diaphragm, surrounding particle which are in constant random motion will be in collision and they in turn travel. The eardrum picks these air movements and sends them as signals to the brain. The brain interprets these motions as sound signals. Some of the properties include speed, frequency which is the number of wave cycles per second, pitch; the higher the frequency the higher the pitch, amplitude; maximum displacement of a soundwave vertically, loudness; the higher the amplitude the higher the loudness, tone/timbre; the quality of sound produced. Loudness and tone/timbre are the main characteristics of music by which people identify sounds.

 Sounds picked by the human ears could be classified in very many ways. This paper particularly is focusing on two categories: according to frequency and according to number of channels used. Frequency as a category has three subcategories which include infrasonic, sonic and ultrasonic. According to number of channels; monophonic and stereophonic. Infrasonic sounds are sound that have a frequency less than 20Hz.these sounds are too low for the human ear to be able to pick and interpret. Sonic sounds are sound whose frequency range between 20Hz and 20kHz. This is the range of sounds the normal human being could listen to. Lastly, ultrasonic sounds are sounds that have a range higher than 20kHz. This range of frequencies are usually very high for the human hearing. Overexposure to sound frequencies of over 20kHz may cause damage to the ear, impeding hearing This, therefore, means that all speakers made for human consumption are programmed to have frequency ranges that vary from 20Hz to 20kHz.

Monophonic sounds or monoaural sounds, in terms of speaker output, will output same audio through one or more speakers. Stereophonic sound or biaural sound, on the other hand will output two different lines of audio through two different outputs/speakers. Stereo systems are able to create the impression of a sound source localization. This is the ability of a human being to locate the source of in a space (Kunchur 3). Stereo sound for the left and right speakers, is achieved through creating difference in timing, frequency, sound pressure levels, dynamics and reverberation amounts. Phantom mono sound source is where the brain perceives two similar sounds from two different speakers; left and right to the left and right ear respectively, as sound coming directly from the front (Ródenas, Ronald and Janssen 268). Ródenas, Ronald and Janssen continued to note that, through interaural time differencing and phase differencing, the brain is able to receive and compare signals upon hitting the ear drum. This enables the lister to determine the position of a sound source.

Stereo sound is very pleasant to listen to because it immerses the listener into a very rich audio experience. Stereo technology has enabled the listener feel a variety of sounds. Stereo technology makes the listener have nice surround of sounds. This makes the listening experience more realistic and in turn more enjoyable. Stereo technology has also shown that aside from just listening experience, there is also the ability to record more than one audio; multi-recording. This is where different audio signals through microphones could be sent to different speakers. Example is in recording a choral session. A choral setup has different voice parts. In recording these individual parts, one would require more than one channel for recording. This type of recording enhances localization for the listener. “…correct localization within a wide listening area is beneficial for all applications where a good stereophonic sound is required: audio, video, or car stereo (Ródenas, Ronald and Janssen 268).”

In conclusion, this paper aimed to highlight how the technological stereo system has made life of the younger generation more pleasant. This, through its application in music. This paper has first shown how sound is reproduced through speakers before it could be processed through either mono or stereo. This paper has also gone ahead to show that sound, within human frequencies (20Hz-20kHz), could be recorded separately and output through separate channels for immersive listening experience, for a realistic and enjoyable listening. Stereo audio has also given way to the feature of multi-recording. Multi-recording has been seen to enhance the listener’s experience through ensuring audio output is of high-quality. This is called dynamism.