vbap4
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## vbap4

vbap4 — Distributes an audio signal among 4 channels.

## Description

Distributes an audio signal among 4 channels.

## Syntax

    ar1, ar2, ar3, ar4 vbap4 asig, iazim [, ielev] [, ispread]

## Initialization

iazim -- azimuth angle of the virtual source

ielev (optional) -- elevation angle of the virtual source

ispread (optional) -- spreading of the virtual source (range 0 - 100). If value is zero, conventional amplitude panning is used. When ispread is increased, the number of loudspeakers used in panning increases. If value is 100, the sound is applied to all loudspeakers.

## Performance

asig -- audio signal to be panned

vbap4 takes an input signal, asig and distributes it among 4 outputs, according to the controls iazim and ielev, and the configured loudspeaker placement. If idim = 2, ielev is set to zero. The distribution is performed using Vector Base Amplitude Panning (VBAP - See reference). VBAP distributes the signal using loudspeaker data configured with vbaplsinit. The signal is applied to, at most, two loudspeakers in 2-D loudspeaker configurations, and three loudspeakers in 3-D loudspeaker configurations. If the virtual source is panned outside the region spanned by loudspeakers, the nearest loudspeakers are used in panning.

## Examples

Example 395. 2-D panning example with stationary virtual sources

      sr      =          4100
      kr      =           441
      ksmps   =           100
      nchnls  =             4
      vbaplsinit         2, 6,  0, 45, 90, 135, 200, 245, 290, 315

              instr 1
      asig    oscil      20000, 440, 1
      a1,a2,a3,a4,a5,a6,a7,a8   vbap8  asig, p4, 0, 20 ;p4 = azimuth

      ;render twice with alternate outq statements
      ;  to obtain two 4 channel .wav files:

              outq       a1,a2,a3,a4
      ;       outq       a5,a6,a7,a8
              endin

## Reference

Ville Pulkki: “Virtual Sound Source Positioning Using Vector Base Amplitude Panning” Journal of the Audio Engineering Society, 1997 June, Vol. 45/6, p. 456.

## See Also

vbap16, vbap16move, vbap4move, vbap8, vbap8move, vbaplsinit, vbapz, vbapzmove

## Credits

Author: Ville Pulkki
Sibelius Academy Computer Music Studio
Laboratory of Acoustics and Audio Signal Processing
Helsinki University of Technology
Helsinki, Finland
May 2000

New in Csound Version 4.07

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