vbapg — Calculates the gains for a sound location between multiple channels.


Calculates the gains for a sound location for up to 64.


k1[, k2...] vbapg kazim [,kelev] [, kspread] [, ilayout]
karray[] vbapg kazim [,kelev] [, kspread] [, ilayout]


ilayout -- index of the speaker layout in the range 0-99, corresponding to a call to vbaplsinit. The default value is 0.


kazim -- azimuth angle of the virtual source

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

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

vbapg calculates the gains that an input signal would have between multiple speakers according to the controls kazim and kelev, and the configured loudspeaker placement ilayout. If idim = 2, kelev 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.

[Warning] Warning

Please note that all vbap panning opcodes require the vbap system to be initialized using vbaplsinit.



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


Here is an example of the vbapg opcode. It uses the file vbapg.csd.

Example 1178. Example of the vbapg opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

; Select audio/midi flags here according to platform
-odac  ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o vbap4.wav -W ;;; for file output any platform

sr = 44100
ksmps = 32
nchnls = 4	;quad
0dbfs  = 1

vbaplsinit 2.01, 4, 0, 90, 180, 270

instr 1

asig diskin2 "drumsMlp.wav", 1, 0, 1		;loop drumsMlp.wav
kaz  line 0, p3, p4				;come from right rear speaker &	
k1,k2,k3,k4 vbapg  180, 100, kaz, 1             ;change spread of soundsource
     printks "spread of source = %d\n", 1, kaz	;print spread value
     outq asig*k1,asig*k2,asig*k3,asig*k4


i 1 0 12 100


Its output should include lines like these:

spread of source = 0
spread of source = 8
spread of source = 17
spread of source = 25
spread of source = 33
spread of source = 42
spread of source = 50
spread of source = 58
spread of source = 67
spread of source = 75
spread of source = 83
spread of source = 92
spread of source = 100

See also

Panning and Spatialization: Vector Base Amplitude Panning


Author: Ville Pulkki
Sibelius Academy Computer Music Studio
Laboratory of Acoustics and Audio Signal Processing
Helsinki University of Technology
Helsinki, Finland
May 2000
Author: John ffitch
July 2012, Sept 2013

New in Csound Version 5.17.13.

Array version new in Csound Version 6.01.