VGMRips

Title	Ecco the Dolphin
Composer	András Magyari,Spencer Nilsen,Brian Coburn
System	Mega Drive, Genesis
Sound Chips	YM2612, SEGA VDP PSG
Tracks	19
Playing time	34:52
Pack author	DJ Squarewave
Pack version	1.05
Last Update	2014-08-26

Import details

• Source: Project2612
• Rating: 6.32 (57803 / 9143)
• Downloads: 12908
• External link: GameBase
• External link: GameFAQs
• External link: SegaRetro
• External link: GiantBomb
• External link: Wikipedia
• External link: Guardiana
• External link: MobyGames
• External link: TheGamesDB (Genesis)
• External link: TheGamesDB (Mega Drive)

As it turns out Sound Test 06 and 12 aren't actually unused! At least, not in the Japanese version.
Sound Test 06 is used for Cold Water which originally used the Opening Theme, and Sound Test 12 is used for the Open Ocean and replaces the original theme.
The theme for The Stomach was also unused in the original release, as that level was only added in the Japanese version.