What they had come up with was an AI that can analyse how sound bounces around a room before reaching the microphone or ear.
“We catch the sound as it arrives at each microphone, backtrack to figure out where it came from, and then, in essence, we suppress any sound that couldn’t have come from where the person is sitting,” says Mr McElveen.
The effect is comparable in certain respects to when a camera focusses on one subject and blurs out the foreground and background.
“The results don’t sound crystal clear when you can only use a very noisy recording to learn from, but they’re still stunning.”
The technology had its first real-world forensic use in a US murder case, where the evidence it was able to provide proved central to the convictions.
After two hitmen were arrested for killing a man, the FBI wanted to prove that they’d been hired by a family going through a child custody dispute. The FBI arranged to trick the family into believing that they were being blackmailed for their involvement – and then sat back to see the reaction.
While texts and phone calls were reasonably easy for the FBI to access, in-person meetings in two restaurants were a different matter. But the court authorised the use of Wave Sciences’ algorithm, meaning that the audio went from being inadmissible to a pivotal piece of evidence.
Since then, other government laboratories, including in the UK, have put it through a battery of tests. The company is now marketing the technology to the US military, which has used it to analyse sonar signals.
It could also have applications in hostage negotiations and suicide scenarios, says Mr McElveen, to make sure both sides of a conversation can be heard – not just the negotiator with a megaphone.
Late last year, the company released a software application using its learning algorithm for use by government labs performing audio forensics and acoustic analysis.