AMBDEC(1)						      General Commands Manual							 AMBDEC(1)

NAME

       ambdec - Ambisonic decoder for first and second order

SYNOPSIS

       ambdec [options]
       ambdec_cli  config_file

DESCRIPTION

       This manual page documents briefly the ambdec and ambdec_cli commands.

       AmbDec  is  an Ambisonics decoder for up to 36 speakers. It can be used for both horizontal and full 3-D systems of first, second and third
       order.  The decoding matrices are fully user-configurable. AmbDec has some advanced features not found on most decoders:

       Dual frequency band operation.  Optimal Ambisonics reproduction requires a different decoder for low  and  high	frequencies.  This  is	so
       mainly  because	human  perception of sound direction uses different mechanisms at low and high frequencies.  The crossover filters used in
       AmbDec are phase-aligned (the two outputs are exactly in phase at all frequencies). The combined response is equivalent	to  a  first-order
       all-pass network, which is very probably inaudible.

       Speaker	distance compensation.	If the speakers are not all at the same distance to the center of the listening area, this must be compen-
       sated by including the right delays and gain corrections.

       Near-field effect compensation.	Ambisonics works by reconstructing the spherical harmonic components of a sound field at the center of the
       listening  area,  using	all  speakers  to synthesize each of them. All non-zero order components show a near-field effect depending on the
       ratio wavelength=distance, and increasing for rising order. One example of this is the well known 'proximity effect' of directional  micro-
       phones  ('directional' is equivalent to 'using non-zero order components'). Except in very large installations, where the speaker distances
       will be large enough so the listening area is not in the near field, this effect must be compensated for  in  order  to	obtain	a  correct
       reconstruction of a sound field.

OPTIONS

       ambdec accepts the following command line options:

       -h     Show summary of options.

       -c FILE
	      Load configuration from FILE.

       -p PATH
	      Load presets from PATH.

       -V VOLUME
	      Set initial volume in dB.

AUTHOR

       ambdec was written by Fons Adriaensen <fons@kokkinizita.net>.

       This manual page was written by Alessio Treglia <quadrispro@ubuntu.com>, for the Debian project (and may be used by others).

								    2010/03/14								 AMBDEC(1)