Hiding the Secrets
Hiding the Secrets is played in three secret levels: E1M9: Military Base, E3M9: Warrens, and E4M9: Fear. Bobby Prince used Sequencer Plus Gold to compose this track.
Hiding the Secrets, as stated above, only plays in the secret levels: E1M9: Military Base, E3M9: Warrens and, if Ultimate Doom is installed, E4M9: Fear. The level E2M9 is also a secret level but it instead uses Untitled.
The internal lump name of the tune in the IWAD file is "D_E1M9" and "D_E3M9" (although both being completely identical, the latter is only found in the registered version).
Instead of playing on the Military Base, Hiding the Secrets, in the Sega 32X console port, plays on the Level 9: Deimos Anomaly (compensating absence of I Sawed the Demons originally applied to play on that level)
Most of the listeners consider the Doom soundtrack arrangement on the 32X port the worst one.
Hiding the Secrets is output to S-SMP and plays on E1M9: Military Base alike to its original PC version, but it does also compensate the absence of I Sawed the Demons alike to 32X version and is applied to play on E2M1: Deimos Anomaly.
Final Doom: The Plutonia Experiment (DOS)