Ostinatos have become an essential part of that modern cinematic/orchestral sound in movies, tv and video game soundtracks. Simply because they can provide so much energy, forward momentum, tension and shape the story curve intensity very effectively.
Essentially, an ostinato is a “persistent” (obstinate) musical motif, phrase or pulse, that focuses on the rhythmic aspect more than the melodic. Even though it can take the form of more “melodic ostinatos” as well, such as in the famous Pirates of the Caribbean soundtrack.
Now, let me share some of my top tips on writing great ostinatos for cinematic and orchestral music:
1. Start with the Main Groove
Think of the main groove of your ostinato, as similar to the main groove of your percussion. In your percussion parts the main groove is played with the low end drums like bass drums, timpani, taikos etc. And the similar aspect of your ostinato is the low string short notes.
2. Add the Main Accents
Accents can be added in many ways, but mainly by the following: dynamics (velocity values), layering (more parts), and finally doubling (in octaves or harmonies). Choose your accents wisely as those will become the “main groove of the main groove” so to say.
3. Add Dynamic Variation
Just like chugging an electric guitar, with your ostinatos you really want every note to have a slightly different sound/tone. Otherwise you risk having that dreaded machine gun effect. Variation per note comes from using a sample library or VST plugin that includes lots of round robins, as well as dynamic layers. Then you should make sure you don’t use the same velocity value for each note, but rather include those small performance differences a real player would have.
4. Don’t forget other Instruments
Even though short strings, and short pulse synth sounds, are the go to sounds for ostinatos in orchestral and cinematic music. What makes the entire ostinato feeling come to life is when you add other instruments to it. Like sforzato or staccato brass for example, or staccato woodwinds in the top end for some airy shimmer. And you should also make sure that you do not simply layer every performance, but actually have variations in the rhythms. However, you do still need to respect the “main groove” and accents.
5. Finish with Details & Spice
The final part is to add the extra spice that will take your overall ostinatos to the highest level. This can come from going in and out with layering parts (not constant layering), it can come from short “transition phrases” that lead into our out from certain points in your sections. It can also come from using different types of articulations dropped in here and there for spicing up the total sound.
But most importantly, you should take advantage of the variation in short note articulations you can use in your specific sample libraries etc. Meaning that you should not be lazy and just use spiccato notes all they way through out. But rather mix it up with staccato, staccatissimo, marcato etc.