Horror movies are, of course, made to make you jump or to sit on the edge of your seat but, if you were to watch one of today's 'scary movies' (this does not, necessarily, work with classics) while your television was muted, there would not be much, on the screen, that would cause you to jump. The film's music supplies you with that fist of fear that balls up in your stomach when the orchestra's string section kicks in, when the bass drum begins to be played, or when the oboe section starts their low, eerie, solo. Actors do not have to be good (even marginally) to make a horror film, the lighting does not have to be good to make a horror film, but the musical score better be good, or you will just have a lot of half clothed teenagers getting killed by crazy people (that's the difference between slasher and horror films; music, rather than tones or silence). I mean, I love laughing at Final Destination (all of them) just as much as the next person and Zombieland is one of my favorite films, but there is nothing like a good classical horror film score to scare you when it comes time for Halloween.
Those classic films all rely on a leitmotif (a theme) in their musical scores, and you will always associate that sound with that movie. When you hear the Halloween theme song, with that steady piano, that feeling of fear begins to creep in as the horn section begins their piece. The film relies on the music to give it something that will trigger real emotion in its viewers; everyone knows that it does not matter how fast Jamie Lee Curtis runs, Michael Myers will still catch up to her just by walking. This idea is reflected in the film's music as, no matter how loud or unsteady the horn section appears to play, the piano keeps the same beat, and notes, throughout the piece; plus, the unease created by the horns is a perfect juxtaposition of the otherwise nice piano piece (if you had never seen the film there would be nothing frightening about those notes). When I was seven, I had no idea how intricately the music was tied to the film (I just knew that my fear of clowns had been further cemented and that I would never trust a man in a white mask again), but the composition is genius.
Something that would make other people appear awful has made John Williams one of the best composers. Jaws is one of the scariest movies of all time, but there is nothing scary about a mechanical shark; Williams took two notes and turned them into an entire piece that matches your normal heart rate, then gradually speeds up. Williams designed a piece that, initially, matches the rate of the human heartbeat, evoking a physiological response that would gradually increase someone's heart rate, essentially, forcing you to experience fear; and when those horns chime in, you know your heart rate picks up just a bit. Picking up the leitmotif discussion from the previous paragraph, this piece is used so often in each of the Jaws films, without varying from that same leitmotif (two notes that mimic your heartbeat) that it has been ingrained in your memory. You automatically associate sharks with that song; if you walk in the tunnel at Seaworld or see a fin at the beach, that song will come to mind.
Nightmare On Elm Street is one of the best horror movies; if you can watch it without having trouble sleeping for a month, you're kind of amazing (or you were older than seven when you first saw it...). The idea surrounding the film is great (you can never escape your worst nightmare) but the music is the thing that makes your skin crawl. Sure, it is gross when that guy's blood is all over his bed, but that is only gory, not scary; the fear comes from those discordant sounds created by any modern keyboard; the vocals backed up by the ever present shrill sound, with the drums kicking up just enough to sound like an echo in the background of the song, before those ever present violins kick in; the music is creepy without the film so, when you see a burned man with knife hands walking through a boiler room while the piece is played, it becomes terrifying. Then, of course, there's the use of a nursery rhyme (something we once considered 'safe'); nothing will make you more afraid of children singing than this song.
There is nothing more discordant, with the hyper trumpet sounds, warring violins, and the underlying 'breathing' sound, than the theme song from Friday the 13th. The breathing picks up every time that Jason is about to appear (you associate the breathing with someone's impending 'death'), and the music follows soon after that. This is one of the most iconic horror films of the 80's, because the music and character are so deeply entwined with one another. If the breathing does not make you sit on the edge of the seat and begin to chant "you're going to die, don't do that" at the television, then the music which chimes in and pricks at your heart rate will.
Psycho may not be as terrifying now as it was in 1960 (especially that iconic fall down the stairs which was so amazing at the time, and is now little more than laughable) but it is one of the best horror films. There's the fact that nothing is scarier than a cross-dressing guy spying on you through a whole in the wall, then killing you while you're defenseless in the shower, but those strings that chime in just in time for the actual crime to take place, continuing throughout the scene and ending with the ominous sound of the horns, was the first time that the musical score of a horror film became so iconic.
There's the fact that horror films just are not as scary today as they used to be; 28 Days Later is classified as horror, and the only scary thing about that movie is when that one zombie-esque guy appears in the window (but he's about to attack a 'bad' guy so you end up rooting for him anyways). People might be afraid of The Grudge or The Ring, but the only scary thing about The Grudge is the sound which the dead woman makes and the only thing alarming about The Ring is how quickly that creepy chick climbs up that well. The fact that these films are not scary is not only because they are missing that aspect of an actual fear (if you do not play on someone's real fears, then you just cannot get a response. There's a reason that the Paranormal Activity films have done so well; I act cool the whole time I'm watching the film, but when I am the only person awake the next morning and I hear a sound, I just know that an entity is going to kill me in the shower.), but because they have no real music. The films have tones, chords, which may be played, but there is no significant theme song which you associate with the villain.
On the other hand, there are those Halloween films which have those hauntingly beautiful compositions; they are just tragic enough to make it into a film that will make you feel something besides fear during Halloween, with their swirling melodies and swelling (rather than striking) violins. Edward Scissorhands and The Corpse Bride (two of Tim Burton's best) have amazing soundtracks, but they are played at a time in the year when you want gore and fear, not tragic loneliness and the combination of a 'happy,' yet pathetically empty and slightly sad ending. Movies like this follow the same rule as the original character pieces; Berlioz's "Symphonie Fantastique" may have been put together wonderfully, with the character's joy and excitement of being with the woman he loves bounding through the orchestral piece, but the song still ends with the anger and fear of the main character being walked to his death before you hear the guillotine drop and the head roll, twice. No matter how beautiful it may be, it's awful and, while inspired, provides the listener with nothing more than a disheartened response of "well, that was nice...".
The use of a leitmotif in each of these horror film scores provide those films with that everlasting creep factor; who does not hate it when those children begin to chant "1,2, Freddy's coming for you..." or when they hear that breathing sound from Jason (the sound which my dad tormented me with for years when I convinced him that five was old enough to handle my first horror movie [I was wrong, do not let your child watch that movie or they will forever be bound to two/three person canoes and will never again go in a kayak]). Honestly, describing some of these film scores as the 'best of horror' is not difficult, per say, because I know them so well, but odd because, growing up, they were the theme songs of my October's and I have grown so used to them; I still cannot justify Halloween as being over unless I have seen Nightmare On Elm Street, Halloween, and Friday the 13th.