We have all heard the famous score for the Spielberg film "Jaws". The eerie two notes that creep into the hushed theater, heightening the viewer's anxiety as an unseen monster approaches to claim its next victim.
The film that terrified an entire generation enough to think twice before stepping into a kiddie pool owes a great deal of its blockbuster success to the auditory suspense created by its intense score concocted by John Williams.
If you are a filmmaker at a stage where you are thinking about working with a composer, it is very important to choose the right match for the project you are creating. For instance you would not want Phillip Glass to score a Kraft mac and cheese commercial for you (although I think that would be an amazing ad). The point is, certain composers have a sweet spot for specific genres of visual media. Many may say that they are versatile enough to do it all, but it is up to you as the decision maker to make that call and follow your instinct on your project.
Through my experience as a filmmaker and working with several different composers on films, commercials and other narratives, I must say that I have the utmost respect for their craft. Great composers have the ability to blend their music seamlessly into a scene to the point where you do not hear it, you feel it subconsciously. They hit beats in the story with their music that adds a whole separate dimension altogether.
I would like to point out that this type of collaboration takes patience on the part of both parties (filmmaker and composer). This is why finding the right fit for you is not only a matter if matching personalities that can work together but also the ability to see eye to eye creatively.
Reiterating my point that the "right" composer is critical to your success, request a short sample of their work specifically in regard to your project. Do not be shy to ask, a production can be made or broken at this stage in the process. Also try to gauge their work ethic as well as how much they have on their plate. Many composers take on several projects at a time and yours may be third in line (which is not a great place to be if you have a deadline).
This process can sometimes feel like a marriage (complete with some bickering) but once you have finished, you are very likely to feel a creative bond and mutual pride in what you have both created. In my opinion, The process is all worth it because filmmaking and production is a collaboration of many talents coming together. It is greater than the individual and in the end that is what makes this business so great.