What is the difference between Zylia A-format and Ambisonics B-Format? Why do ZYLIA ZM-1/S microphones have 19 audio channel?
Zylia A-Format is the raw recording of the 19 individual omnidirectional capsules in ZYLIA ZM-1/S microphones.
A-Format is specific to the ambisonics microphone model since each microphone capsule has a different space position, distance, or even polar patterns.
B-Format is the standardized format derived from the A-Format. The first channel carries the amplitude information of the signal, while the other channels determine the directionality through phase relationships between each other. B-Format tracks contain a speaker-independent representation of a sound field. You can use B-Format in various ambisonic tools and Digital Audio Workstations to mix it.
The B-format components can be combined to derive virtual microphones with any first-order polar pattern (omnidirectional, cardioid, hypercardioid, figure-of-eight, or anything in between) pointing in any direction. Several such microphones with different parameters can be derived simultaneously to create coincident stereo pairs (such as a Blumlein) or surround arrays. (cited: https://en.wikipedia.org/wiki/Ambisonics)