Sound effects behave differently on level 8

Normally in Vanilla Doom, sound effects decrease in volume with distance, with a cutoff at 1200 units. Sound effects originating at a distance of more than 1200 units from the player are not heard. This behavior is different on level 8. This affects level 8 when playing under any episode of Doom 1 as well as MAP08 of Doom 2 and Final Doom. When playing on level 8, sound effects are not cut off. Furthermore, the effect of distance on volume is reversed. Close sound effects are quiet while sound effects at a distance are loud. As the Boss levels in Doom 1 all occur on level 8, it is possible that this behavior was intended so that the player could always hear the boss monster from any distance. == Demonstrating the effect == The effect varies depending on the sound effect volume setting, and is more pronounced at low values. To demonstrate it: # Start Doom and warp to level 8 (mission 8 of any episode or MAP08). # Go to the sound menu and move the sound effect volume slider to minimum. # The effect should be immediately noticeable in that sound effects at even a short distance can be heard despite the volume setting being at zero. One demonstration can be performed by firing a rocket at a distant wall. The rocket will be heard hitting the wall but will not be heard when fired. == Technical == The cause of this is found in s_sound.c in the Doom source code:  // From _GG1_ p.428. Appox. eucledian distance fast. approx_dist = adx  ady - ((adx