Many Entities such as Descriptors, Bands, and Instruments provide short
audio examples that allow users to have a sense of what their choice
may sound like before committing to a full render. These are referred to as
Previews. Every entry in the list will provide a
url to the audio file and a
content_type specifying what file type the URL points to (typically
"audio/mp3"). An Entity can have one or more Preview.
It is worth noting that there is no actual correlation between what is depicted
by a Preview and the music you will receive if you use the Entity it is
associated with. Instruments behave differently based on the Descriptor and
any other Instruments are used with them. The same Descriptor will sound
very different with entirely different Instruments. Even if it were practical to provide
Previews for every possible combination, any timeline (provided it does not
random_seed) will sound different from render to render by design.
However, some use cases find it advantageous to provide hints of what is available, and Previews are the best option.