According to a number of studies (do a search on “music for productivity”), music that is highly engaging, such as songs we enjoy — especially those with a lot of lyrics — are good for repetitive work. This is probably because they stimulate areas of the brain otherwise deadened by rote activity, which can be accomplished largely without “interference” from our higher brain centers. On the other hand, lyric-less music, silence, or even are best when we need to concentrate, when the music we enjoy might prove a distraction.
I would like to propose a third category. In the physics of waves (including sound), constructive interference is “the intersection of two or more waves of equal frequency and phase, resulting in their mutual reinforcement and producing a single amplitude equal to the sum of the amplitudes of the individual waves.”
In my writing, music provides such constructive interference, but as the studies referenced above indicate, not all music is equally productive. In the drafting and plotting stage, I tend to listen to music that complements the characters and/or narrative I am composing, even where that music is lyric-filled and engaging. At this point in the process, I’m merely typing notes, not even whole sentences let alone a coherent narrative, and music that puts my subconscious into a relevant mood is highly fecund.
This is why each of my characters gets a theme song, sometimes more than one. For example, I looped the following song from Gustavo Santaolalla while creating my Amazon-born, French-raised shaman-chef, Etude Etranger, whose defining traits — depth, mystery, power, ambivalence, hope — find voice in the great falls at Iguazu, which arise from mystery and disappear into uncertainty, and which are never the same from moment to moment.
But my other character from South America, the superhuman Hispanic-mulatto Xana Jace, needed something entirely different, a song that captured both her life-threatening illness and the loss of her son yet still left the listener with the certainty that she could become something much, much greater. This song directly inspired the scene towards the end of Episode Two of THE MINUS FACTION where Xana, on her knees, about to be defiled in front of a crowd, decides to stand and fight despite the cost to herself and those she loves.
But highly engaging songs like this are often not what I listen to while in heavy composition. For that, I need engaging and mood-appropriate music with little-to-no lyrics to muck up my wording engine. The following song has been getting heavy rotation recently as I work on the fourth course of my occult mystery, THE HERETIC ARCANUM, which features a little boy, Olafur, around whom swirls some very unusual phenomena.
In fact, Tangerine Dream is good for inspiring words regardless of the project, as are soundtracks to movies. After all, such music was specifically composed to elicit constructive interference — to augment an audio-visual narrative rather than distract from it. Trailer music in particular worked well for Episode Four of my superhero-ish serial novel THE MINUS FACTION. It is a reminder to me that each installment needs an emotional “hero moment,” a singular crisis where one or more of the characters are given a chance to walk a difficult but higher path, and that the entire plot should pivot on that fulcrum.
Finally, there are just some songs that I love so much, they are an enjoyment and an inspiration no matter what I am doing.