Most interview coaching focuses on what you say. Almost none of it addresses how your voice is actually landing.
That's a problem, because interviewers are forming impressions about your confidence, competence, and enthusiasm from your vocal delivery long before your words register.
The Four Signals That Matter Most
1. Filler Density
Fillers (um, uh, like, you know, kind of, basically) are normal in conversation. They become a problem when they appear at a rate above 4-5 per 100 words, or when they appear in high-stakes moments like answer openers or result statements.
A filler at the beginning of a sentence signals that you're buying time. An interviewer reads this as uncertainty.
Baseline: Aim for under 3 fillers per 100 words on structured answers.
2. Pitch Range
Pitch range, measured in Hz, is the difference between your lowest and highest note across an answer. A narrow pitch range (often called "flat delivery") makes everything sound equally important, which means nothing lands.
What interviewers hear with flat delivery: "Smart candidate, but hard to stay engaged with."
What to do: Pick the single most important sentence in each answer, usually your result or your decision, and say it with more energy. You don't need to be dramatic. You need contrast.
3. Speaking Pace
The ideal interview pace is 130-160 WPM. Faster than that and you sound rushed or anxious. Slower than 120 and you start to lose the interviewer's attention.
Most nervous candidates speak *faster* than normal, not slower. This is the opposite of what it feels like in the moment.
What to do: Record yourself. Most people are surprised how fast they actually talk under pressure.
4. Amplitude Variation
Amplitude variation measures how much your volume changes across an answer. Low amplitude variation (monotone volume) reduces perceived energy and enthusiasm.
The fix here is simple: key points should be louder. Transitional phrases like "and then" or "so the result was" should be softer. This creates natural emphasis without feeling theatrical.
The Compounding Effect
None of these signals kills an interview on their own. But a candidate with flat pitch, high filler density, fast pace, and low amplitude variation will consistently get scored lower on perceived confidence, even when their actual answer content is strong.
The interviewer won't know why. They'll just feel like the candidate "wasn't quite there yet."
Signal measures all four of these signals on every spoken answer and trends them over time. Most users see measurable improvement in filler density within 5-7 sessions once they can see the data.