Speaking at Dmexco, Khan appeared to be taking a veiled shot at Facebook, which has encouraged brands to create video ads that work without rather than with sound.
"When you buy ads without sound, you're not buying video," said Khan. "You're paying video price for a moving banner ad."
He acknowledged that he was "biased", since Snapchat measures its own video ads for audio effectiveness. The company has partnered with ad measurement company Moat, which looks not just at viewability, but also hearability.
Khan said two-thirds of Snapchat's ads are played with sound. "We believe that if you tell a story without sound, it's not that powerful." He demonstrated with a trailer for horror film The Visit, noting that it made little sense with the sound off.
This is in direct contrast to Facebook, which last month claimed that people prefer to have the choice to "opt out" of sound. The company has found in its own research that 80% "react negatively" to both the ad platform and brand when sound plays unexpectedly on its mobile feed.
Videos are automatically set to play silently on Facebook, whereas on Snapchat they are automatically set with the sound on.
Snapchat now boasts 150 million daily active users and, Khan said, is increasingly used by a wider demographic. Though often pegged as the social media platform of choice for teenagers and young millennials, Khan said more than half of its users in the US are older than 25. "Many are older than 40," he added.