Sounds Good? Your Ad’s Voice Is Doing More Than You Think

Sound is one of advertising’s most overlooked levers. While the research on visual identity, copy, and media placement is extensive, the strategic role of voice remains surprisingly underexplored, despite being present in virtually every audio and video ad in existence.

For any brand running campaigns with a voice element, this is a gap worth closing. Most advertisers obsess over what their message says. The real power often lies in how it sounds. Vocal characteristics, including pitch, accent, and numerosity, consistently shape how people perceive and remember advertising messages. In other words, how a brand sounds shapes attitudes and behaviours toward it. But how?

Vocal pitch: the frequency of persuasion

Vocal pitch is a defining characteristic that conveys personality and influences how a message is received, and its effects extend well beyond advertising. In politics, research across controlled experiments and actual U.S. House elections found that candidates with lower-pitched voices won a larger vote share because voters perceived them as stronger and more competent. Margaret Thatcher is a well-known example: she reportedly worked with a voice coach and used exercises such as humming to lower her voice, to sound more authoritative and powerful. These are largely unconscious judgments, which makes them all the more relevant to advertising.

Research shows that low-pitched female voices generate the most favourable ad and brand attitudes and improve recall, making them particularly effective for new brands entering a category. For male voices, lower pitch is more strongly associated with authority and expertise, which makes it well-suited to categories where trust and competence are central to the decision.

For brands, this translates into a clear principle. Pitch selection should be intentional and grounded in what the audience needs to feel, confidence, trust, authority, but it must remain credible. In a mature category where a new product line needs to stand out, a low-pitched female voice can improve recall and brand attitude. In insurance or financial services, where expertise is the deciding factor, a lower-pitched male voice reinforces the perception of competence. The starting point is always the behavioural outcome you are trying to achieve.

Accent familiarity: the sound of trust

The perceived familiarity of a voice strongly shapes how credible a message sounds. But familiarity is not just about clarity, it is about identity. When people hear an accent that matches their own, it activates in-group bias: a well-documented tendency to extend greater trust and liking to those we perceive as similar to us. The voice becomes a social signal before it becomes a persuasive one.

This effect is reinforced by processing fluency. A familiar accent is easier to process, and that ease is misattributed to the message itself, making it feel more truthful and more credible. Studies show that radio commercials voiced by foreign-accented speakers produced lower purchase intentions, product attitudes, and perceived speaker competence compared to those using standard accents. The extra cognitive effort required to follow an unfamiliar accent leads listeners to perceive the message as less truthful.

For brands running activity across multiple regions, this has a direct practical implication. An automotive manufacturer advertising across the UK would not be well served by a single standard accent across all markets. A Scottish voiceover running in Scotland, a Welsh accent in Wales, and so on, the same message adapted by region, activates in-group familiarity and reduces processing friction simultaneously. The product does not change. The trust it earns does.

Voice numerosity: when more voices speak louder

We are very sensitive to sounds, and especially to human voices. However, because we are constantly surrounded by many different sensory signals, we cannot pay attention to everything at once. One important feature that makes something stand out is change in the stimulus. Our brains have automatic mechanisms that detect such changes and send a signal to redirect our mental resources. Because of this, when the narrator’s voice changes in a video, that change is likely to grab people’s attention and make them focus again on what is being said.

Indeed, recent evidence highlights the “voice numerosity effect”: the finding that using more than one voice in a persuasive message can enhance attention and willingness to pay. Surprisingly, this effect persists even when consumers are minimally distracted. However, when the ad conveys complex information, a single consistent voice remains more effective.

In the FMCG sector, a snack or beverage campaign might use several alternating voices to create a sense of energy and to grab attention, thereby increasing willingness to buy. The decision, then, is not simply how many voices to use, but what role the voice is playing. In low-involvement, high-energy categories, multiple voices create stimulus change and drive attention. Where the message carries complex or technical information, a single consistent voice preserves comprehension and credibility.

Conclusion

Across the evidence, one insight stands out: vocal characteristics systematically shape how advertising is received, and a single approach will not work across all contexts. Pitch signals confidence and competence. Accent familiarity activates trust through identity. Multiple voices drive attention in ways a single voice cannot. Each characteristic is a lever, and each lever works differently depending on the audience, the category, and the behavioural outcome you are trying to achieve. Getting it right means treating voice as a strategic decision.

If you are looking to make your advertising more effective, we can help. Sounds good?