It is true that many viewers watch reels without sound, which is why captions and on-screen text matter so much. But the viewers who do listen, and they are a large and valuable share, judge your reel heavily by its audio, and poor audio is one of the fastest reasons to swipe away. Muffled voice, music that drowns out speech, jarring volume jumps, or a single flat audio track all signal low effort, even when the visuals are strong. Sound design is the craft of layering music, voice and effects so that each supports the others, creating an audio experience that holds listeners as effectively as good visuals hold watchers.

Think of reel audio as three layers. The base layer is music, which sets mood and energy and provides rhythmic structure. The middle layer is voice, whether spoken narration, dialogue, or voiceover, which carries information and personality. The top layer is sound effects, short sounds that punctuate actions, emphasise moments, or create transitions. When these layers are balanced, the reel feels polished and professional. When one layer dominates or the layers clash, the reel feels amateur, no matter how good the footage looks. Balancing layers is a skill that improves every reel you make.

The most common sound design mistake is music that is too loud for voice. As a rule, music should sit underneath speech, audible enough to set mood but quiet enough that every word is clear without straining. If you have to choose between music and voice clarity, choose voice, because viewers forgive a quiet track but not an inaudible explanation. Use volume automation: lower the music slightly when someone speaks, raise it during visual-only moments, and let it swell briefly at emotional peaks. These small volume movements make the audio feel alive rather than flat, and they guide the listener's attention to what matters in each moment.

Sound effects should be used sparingly and purposefully, not as decoration on every cut. A whoosh on a transition, a pop when text appears, or a subtle riser before a reveal all help the viewer feel the edit, but effects on every single cut quickly become irritating and distract from the content. Choose effects that match the visual action: a swoosh for a fast camera move, a click for a text appearance, a thud for an impact. Keep effects short and at a lower volume than the voice, so they accent rather than interrupt. One well-placed effect per few seconds is usually enough; more than that, and the audio becomes noise.

Start with clean voice recording, because no amount of mixing fixes muffled or echoey audio. Record in a quiet space, close to the microphone, and away from reflective surfaces that create echo. A phone in a quiet room often sounds better than an expensive microphone in a noisy one, so prioritise environment over equipment. Then edit voice first: remove pauses, filler words and breaths that break flow, and only then add music and effects around the cleaned voice track. This order ensures the voice remains the backbone of the audio, with other layers supporting it rather than competing with it.

Finally, always check your reel's audio on a phone speaker, not just on headphones, since most viewers will hear it that way. Phone speakers lose bass and detail, so a mix that sounds rich on headphones may sound thin or muddy on a phone. If the voice is still clear and the music still sets mood on a phone speaker, the mix works. If not, adjust levels and try again. Good sound design is invisible when it works: viewers simply feel that the reel is professional and engaging, without knowing why. That feeling is what keeps them listening to the end.