Soundtrack Research:

In a horror trailer, there are always eerie soundtracks, dramatic/jumpy sound effects and relative ambient sounds. In trailers, sound is used effectively to lure in the audience and keep them feeling tense at all times. I feel a good horror film requires a soundtrack including chimes and whispers enabling audiences to feel engaged and suspicious throughout.

SOUNDTRACK-
The soundtrack in a horror trailer usually presents itself as mellow and mysterious. The creators like to keep the viewers feeling tense and unaware of whats about to happen.
https://www.youtube.com/watch?v=ZOrxwqvfD2E - I found this piece on Youtube, it's a non copyrighted horror soundtrack. The music included a mellow soft creepy tune which suddenly becomes really low with bursts of different sound effects making the audience jump and feel frightened. However, I feel this soundtrack is too child themed like suggesting it could be used in a horror film about dolls and toys, 'Annabelle'.
https://www.youtube.com/watch?v=FgB_L7Os5OA&index=19&list=PLDcPimbLEWH_w_l05-0Yt25qP2pjqv9Z4 - I also found this non copyrighted tune, which sounds very much like whistling winds and natural animal noises. I feel this piece of music is effective with keeping viewers engaged as well as displaying the horror genre.
I prefer the second tune due to it having a better effect on the audience and not being too dramatic. I feel this one isn't too mellow or sound fake when the sound effects become involved.

SOUND EFFECTS-
In all horror film, sound effects including slashing, drops in music, blood gushing and sinister movements are all involved at some point of the trailer/film.
https://www.youtube.com/watch?v=bPe-FsZa9ts&list=PLlKkIChXEU9pOC7djnf1qjPJikuG-N2C8- This first sound effect is extremely cliche, a scream. These sound effects are used throughout horrors whether someone is being attacked, killed or frightened. They are also effective when making viewers jump as they are very loud and high pitch.
https://www.youtube.com/watch?v=mBzgvb7uLyM&index=2&list=PLlKkIChXEU9pOC7djnf1qjPJikuG-N2C8- Here we have someone knocking at a door and footsteps. I feel this sound effect is especially important as the knocking always leaves you feeling tense and sympathise for the character on screen. The footsteps also make you feel as if someone is watching you and coming for you.
https://www.youtube.com/watch?v=HSFzujJQDxs&index=23&list=PLlKkIChXEU9pOC7djnf1qjPJikuG-N2C8- To get a dramatic effect, the weather is usually always raining with a thunder storm. The use of the thunder sound effects makes it seem more real and thrilling. The negative weather gives a negative perception on the film.

AMBIENT SOUND- 
Ambient sounds in horror trailers include whistling winds, footsteps and other background noises. Ambient sounds are usually diegetic as they would be heard on screen.
https://www.youtube.com/watch?v=RBUtBrk7yzo- Here is a piece of non copyrighted music demonstrating howling winds. This is effective as it would be used in the background of the trailer to help create an eerie effect.

The soundtrack used in 'IT' one of the films that inspired us includes circus like themes and repetitive chime music. This is effective when portraying the clown as the music already sounds concerning, however, the murderous clown makes it much more frightening and suspicious. We hope to use this in our trailer as it creates a tense atmosphere for the viewers and audience.