How to make monsters not alert to sound

[redninja_1]

I'm making a TC and every time i shoot through a linedef portal, the monsters on the other side get alerted. Is there any way i can fix this?

[Nine Inch Heels]

There is nothing the "fix" because things waking up to sound is how the engine is supposed to work UNLESS you give monsters the "ambush/deaf" flag in doombuilder.

 

Alternatively you could use sound blocking linedefs to prevent sound from propagating in uncontrolled manners.