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Categories: Audio - Overview


Audio collections can be found in most libraries. Many options are available for people who enjoy listening to the world around them. Audiobooks can bring reading alive for nonreaders or for people who like to listen while driving or working. Other spoken word materials such as comedy programs and "how-to" audios have informational, instructional, or entertainment value. Of course, music may be the most popular audio resource. Coming in dozens of styles, everyone in the family can find something they enjoy. From spooky Halloween sound effects to whale songs, there are audio materials that focus on the sounds around us.

Philadelphia ChickenIn some cases, an audio format is combined with other media formats. For instance, instructional audio recordings sometimes come packaged with books and posters. Or, audio files are available for download from publisher websites. Some children's books come with a CD containing narrative, music, and other sound elements. For instance, Philadelphia Chickens by Sandra Boynton contains the book and CD of an imaginary musical revue. The first half of the book contains lyrics and illustrations, while the second half includes musical notations for each song. The cast includes famous acts such as Meryl Streep and Kevin Bacon.

The Value of Audio and Music

The listening experience can be stimulating, relaxing, and emotional. Whether getting lost in a symphony or crying at the ending of a good audiobook, sound can have a tremendous impact on our lives.

There are many elements to literacy. One aspect is “oral literacy”; the ability to convey ideas through auditory channels. An important aspect of oral literacy is listening. Like other literacy aspects, students must learn to be good listeners. This can begin at an early age with parents reading books aloud. Unfortunately it often ends when children learn to read themselves Audiobooks are a great way to extend listening practice through a lifetime. Whether listening to an iPhone in the car or popping in a CD at the beach, there are many opportunities for listening.

Along with listening to the spoken word, music is another an important element of our world. The more people are exposed to a wide range of music, the more likely they are to appreciate and seek variety in their listening. Music intelligence, one of Howard Gardner's ideas of multiple intelligences, is the ability to produce and appreciate rhythm, pitch, and timbre and have an appreciation of the forms of musical expression. Music is for the whole brain, possibly the first of the intelligences to develop.

Audio Formats

Analog technology began when Thomas Edison first recorded sound waves on a piece of tin. Later this analog wave was stored on vinyl records (called mechanical recording) and tape including reel-to-reel and 8-track (called magnetic recording). You'll still find vinyl records in many schools and libraries. Audio cassettes are the last remnants of analog audio recording.

From compact discs to MP3s, we now live in a digital world. Digital recording technology has high fidelity and perfect reproduction (also called optical disc technology). In other words, the sound is very close to the original and it sounds the same every time you play it. Analog waves are converted into streams of numbers and stored on the compact disk. CD players then convert the data back to an analog wave that's heard through amplified speakers. The audio files (MP3, RealAudio, WAV) found on the Internet are stored as digital audio files.

Since the early 1980s, CDs have been the recording standard. CDs containing 2 channels (for stereo sound) can store up to 74 minutes of music. About 783 megabytes fit on a 12 cm diameter plastic disk that's only 1.2 mm thick. Information is placed on a single spiral track of data that starts in the middle of the CD and moves outward.

Over the past decade, digital audio has gradually overtaken CDs as the preferred audio format for audiobooks, podcasts, music, and other audio experiences. According to the International Federation of the Phonographic Industry (IFPI), digital sales passed CDs for the first time in 2014. However CDs continue to be popular, particularly in library settings.

Acccording to Nielsen's 2016 Music Mid-Year Report,

"audio has surpassed video as the leading streaming format in 2016. Audio share of streaming is 54% in 2016, growing from 44% through the first six months of 2015.
Digital purchasing has seen the largest decline of all formats, with digital tracks down 24% and digital albums down 18%. However, factoring in the gains in streaming, total digital consumption is up 15%.

Vinyl continues to become a bigger piece of the physical music business. Vinyl LPs now comprise nearly 12% of the physical business in the first half of 2016."

The digital format is a popular technology for music compression. Digital technology has taken center stage because of it's high quality and high compression. This is accomplished by reducing the number of bytes needed to reproduce a sound without reducing the quality. A 32 MB song on a CD only takes 3 MB on MP3. The files are also easy to share because they download fast and take up much less space than other storage systems. MPEG is an acronym for Moving Picture Experts Group and MPEG Audio Layer-3 (MP3) is the sound compression system.

smallLamb Reflection
Growing up in Iowa, my teacher put great emphasis on Iowa history. My class would sit in a circle around the reel-to-reel audio tape player and listen to fascinating stories about topics like the button factories along on the Mississippi River in the 1800s. As I watched the audio tape spin around and around on the reel, I was captivated by the narrator's voice as he declared Muscatine, Iowa as the Pearl Button Capital of the World.

Today's teacher librarians would have many more options for helping learner explore Iowa history. Although the old tape players are gone, audio is still a great option. For example, the Harvesting the River website contains images, video, and even audio related to the button business in Iowa. We might listen to the folk music of the people who settled Iowa, hear to the call of the state bird, the Goldfinch, and enjoy an audiobook by an Iowa author.

Accessing Online Collections

The walls of libraries have become transparent as librarians explore ways to bring remote collections to library users. From music to famous speeches, the Internet brings the world of audio into the library.

The term "digital audio" means that sounds are represented in the form of numbers that an electronic device can read. Digital audio can be shared through media such as CDs and DVDs, but it can also be shared over networks such as the Internet. Many formats are used to store the files including MP3.

In addition to the audio you hear through traditional broadcasts such as radios, there are two other ways to access remote digital audio collections. They can be downloaded or streamed. In some cases the end user can choose which method they prefer. In others, only one option is available.

Downloaded audio is copied from a remote web server onto a computer hard drive, MP3 player, CD, DVD, or other storage device such as a smartphone or tablet. Although many types of files can be downloaded including .au, .wav., and .midi, the MP3 format is by far the most popular for music files. High quality and small file size are two of the reasons.

Streamed audio is also downloaded from a remote web server, but the files are only temporarily stored while they are being played.

guardiansStreaming audio is a method of delivering an audio signal to your computer over the Internet. Streaming differs from downloading Internet audio in one important way. Instead of having to download a file completely before being able to listen to it, listeners begin hearing the sound as the first portion arrives on the device.

As the audio data arrives it is buffered for a few seconds and then playback begins. As the audio is playing, more data is constantly arriving (or streaming). As long as listeners continue receiving a constant stream of audio data, they should hear uninterrupted audio. Think of the buffer as a "open funnel" that is continually being topped off with more data. As long as there is data flow into the funnel, it will continue to pour out of the tube - - and be played through the device. In other words, as long as there is data in the buffer you will continue to hear sound. Unfortunately the buffer "funnel" can empty due to congestion on the Internet which interrupts the receiving of data. But if you have a strong internet connection, streaming audio is generally not a problem.

Also with streaming there are no audio files left behind on your device such as computer of smartphone. The audio data is only there temporarily and then is discarded; whereas a downloaded audio file can be copied, stored, and played over and over again.

To learn more, go to Wikipedia: Streaming Media.

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