The innovation is potentially going to be most helpful in public areas: hotels, retailers, museums, transport hubs and parks, for instance, where the background music may broadcast information about the venue or the enterprise (and about how to log on to the native Wi-Fi network) in addition to adding to the ambiance.
You may get details of an exhibit beamed to your phone in an art gallery, or news of special gives in a department store, or the times of the next trains, without you having to touch your phone.
The researchers behind the technique, from ETH Zurich in Switzerland, say the changes the information transmission makes to the music are imperceptible. The more information that wants shifting although, the more heavily the audio file must be modified – speeds of around 200 bits or 25 characters per second are possible without a noticeable change.
“After we hear a loud note, we do not notice quieter notes with a slightly greater or lower frequency,” says another of the ETH Zurich researchers, Manuel Eichelberger. “That means we are able to use the dominant, loud notes in a chunk of music to hide the acoustic data transfer.”
Music with several dominant notes works best for the method – so think the latest pop hits rather than subtle background music.
A map to the modified notes is put within the 9.8–10 kHz frequency range, part of the frequency spectrum that’s barely picked up by the human ear. The ultimate step of the method is the microphone on a smartphone, which could be primed through an app to capture the information being sent.
In an industry gearing up for the arrival of 5G, it is interesting to see something much slower however much more convenient get proposed and demonstrated. Embedding data in music could be another way of keeping our phones connected within the years ahead.