reverbedit

The reverbedit console command allows to create REVERBS lumps in real-time. Using reverbedit will set the game in windowed mode automatically if you were playing in full-screen. Using alt-tab or by calling up the menus to free the mouse cursor, you can shift the focus from the game window to the reverbedit windows and fine-tune settings, then you can move back to the game window to listen to the result, unless you uncheck the "test in level" checkbox.

The editor showing a default environment

Although reverbedit does not let you change already-defined environments, you can create new ones based on an existing one. Once satisfied by the result, you can click on "save" to write the desired environment or environments to a text file which you can then use as a REVERBS lump.

Hitting the "escape" key or clicking on the "done" button will close the reverbedit window.

Selecting an existing environment to use as a template to create a new environment