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.

However, this rule does not apply 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.

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 from any distance. However, the sound effects for some of the bosses (the Cyberdemon and Spider mastermind for example) always play at full volume anyway, making such a check redundant.

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 < ady ? adx : ady)>>1); if (gamemap != 8  && approx_dist > S_CLIPPING_DIST) {    return 0; }

This code calculates the distance of the sound from the player. If the sound is greater than the clipping distance (1200 units), the function returns and the sound does not play. However, a specific test is made to see if the current level is level 8. If so, there is no distance cutoff.