Audio logo is a short, distinctive piece of music designed especially to represent a specific brand name.
It appears on T.V. and radio spots along with a visual logo and it tends to be the " leitmotif " of the company or the product that is being displayed.
See the "making of ", of one of the best audio logos have ever been composed.
In this case the product that is being advertised is the orchestra itself that performs and records the music for the audio logo.
Audio logo is also referred sometimes as Sonic Logo or Sonic ( Sound ) Branding.