- published: 03 Feb 2015
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3D audio effects are a group of sound effects that manipulate the sound produced by stereo speakers, surround-sound speakers, speaker-arrays, or headphones. This frequently involves the virtual placement of sound sources anywhere in three-dimensional space, including behind, above or below the listener.
3-D audio (processing) is the spatial domain convolution of sound waves using Head-related transfer functions. It is the phenomenon of transforming sound waves (using Head-related transfer function or HRTF filters and cross talk cancellation techniques) to mimic natural sounds waves, which emanate from a point in a 3-D space. It allows trickery of the brain using the ears and auditory nerves, pretending to place different sounds in different 3-D locations upon hearing the sounds, even though the sounds may just be produced from just 2 speakers (dissimilar to surround sound). [Note that, transfer function is a function that depict the relationship between an input and the output of a system. It’s a fraction representation with the denominator not equal to 1, if there’s feedback in the system. If the transfer function e.g. Z-transform is localized to the unit circle (or bi-unit circle or tri-unit circle for 2-D and 3-D cases respectively), it then becomes the Multidimensional Fourier Transform (see Multidimensional_transform) or the frequency response of the system.]
Audio signal processing, sometimes referred to as audio processing, is the intentional alteration of auditory signals, or sound, often through an audio effect or effects unit. As audio signals may be electronically represented in either digital or analog format, signal processing may occur in either domain. Analog processors operate directly on the electrical signal, while digital processors operate mathematically on the digital representation of that signal.
Audio signals are sound waves—longitudinal waves which travel through air, consisting of compressions and rarefactions. These audio signals are measured in bels or in decibels. Audio processing was necessary for early radio broadcasting, as there were many problems with studio to transmitter links.
"Analog" indicates something that is mathematically represented by a set of continuous values; for example, the analog clock uses constantly moving hands on a physical clock face, where moving the hands directly alters the information that clock is providing. Thus, an analog signal is one represented by a continuous stream of data, in this case along an electrical circuit in the form of voltage, current or charge changes (compare with digital signals below). Analog signal processing (ASP) then involves physically altering the continuous signal by changing the voltage or current or charge via various electrical means.