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 compensated 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 microphones ('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)