ambdec - Ambisonic decoder for first and second order
This manual page documents briefly the 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
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.
accepts the following command line options:
- Show summary of options.
- -c FILE
- Load configuration from FILE.
- -p PATH
- Load presets from PATH.
- -V VOLUME
- Set initial volume in dB.
ambdec was written by Fons Adriaensen <firstname.lastname@example.org>.
This manual page was written by Alessio Treglia <email@example.com>,
for the Debian project (and may be used by others).