Joint (audio engineering)

In audio engineering, joint refers to a joining of several channels of similar information in order to obtain higher quality, a smaller file size, or both.

Joint stereo

The term joint stereo has become prominent as the Internet has allowed for the transfer of relatively low bit rate, acceptable-quality audio with modest Internet access speeds. Joint stereo refers to any number of encoding techniques used for this purpose. Two forms are described here, both of which are implemented in various ways with different codecs, such as MP3, AAC and Ogg Vorbis.

Intensity stereo coding

This form of joint stereo uses a technique known as joint frequency encoding, which functions on the principle of sound localization. Human hearing is predominantly less acute at perceiving the direction of certain audio frequencies. By exploiting this characteristic, intensity stereo coding can reduce the data rate of an audio stream with little or no perceived change in apparent quality.

More specifically, the dominance of inter-aural time differences (ITD) for sound localization by humans is only present for lower frequencies. That leaves inter-aural amplitude differences (IAD) as the dominant location indicator for higher frequencies. The idea of intensity stereo coding is to merge the lower spectrum into just one channel (thus reducing overall differences between channels) and to transmit a little side information about how to pan certain frequency regions to recover the IAD cues.

Stereophonic sound

Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term "stereophonic" applies to so-called "quadraphonic" and "surround-sound" systems as well as the more common two-channel, two-speaker systems. It is often contrasted with monophonic, or "mono" sound, where audio is heard as coming from one position, often centered in the sound field (analogous to a visual field). In the 2000s, stereo sound is common in entertainment systems such as broadcast radio and TV, recorded music and the cinema.

The word stereophonic derives from the Greek "στερεός" (stereos), "firm, solid" + "φωνή" (phōnē), "sound, tone, voice" and it was coined in 1927 by Western Electric, by analogy with the word "stereoscopic".

Into the Clouds

Into the Clouds is a single by Swedish duo The Sound of Arrows. Later in December 2, 2009 was released EP.

Video clip

Track listings

Side A

Side B

Personnel

References

External links