Why I didn't use the scream in my trailer

Here is the video clip of Grant standing behind Abby in a dark room. When the lights go off she is supposed to scream. The scream sounds very grainy because of the poor quality of the microphone on the camera (and I wasn't allowed to use an exterior microphone becuase we don't have any in our media department).

Script:

[Dark room] Camera angle, head shot - medium close up

Abby: [holding torch which is starting to flicker, Grant is behind her as the clown. the torch turns off and she screams]

However, I did start to use the scream. I thought if I took the clip, extracted the audio, cut the audio down so it was only the scream and went onto audio filter I could get rid of the grainy audio that was caused by the bad quailty microphone on the camera. But how ever many times I tampered with the sound it either made it worse or didn't change the grainy sound.

I was going to put the audio clip of the scream after the flashing clip of Grant and the clown when there is a fade to black before the title comes up. I was going to put the audio so it would scream as the title came up.

After trying and failing to get the scream audio to work I didn't use it. I then continued editting my trailer and found that the trailer is more effective without the scream. This is because you don't need to add a scream to imply fear or horror.

Below is a trailer to a new horror film that is coming out soon, if it isn't out already. It is called "Insidious". There are no screams in this trailer and yet I believe it is quite terrifying.