How is one supposed to binge-watch streaming TV on their phone, listen to music or play computer games in peace when faced with such Sisyphean challenges? As with many other things in the modern world, science has the answer — noise cancelling headphones, which block out external noise and let the sound of whatever it is you actually want to be listening to come through, unsullied by the distractions of the outside world. University of Queensland School of Information Technology and Electrical Engineering research fellow and lecturer Dr Konstanty Bialkowski said there were two types of noise cancelling technologies for headphones — passive and active. “Passive is like having a cup around your ear that reduces high-frequency noise; the other type is active cancellation — that’s for low-frequency noise,” he said. “High frequency could be people talking or high-pitched squealing, low frequency is low-pitched hum like a car engine, aeroplane engine or a fan. The low frequency stuff is very repetitive and that’s really easy to actively cancel.” Dr Bialkowski said one way to describe how active cancellation worked was to think of it as being like ripples in a pond. “If you made a ripple which was the complete opposite of the other one the effect is zero — it cancels it out,” he said. “That’s what’s happening in the headset. It has a microphone and it knows the distance between the microphone and your ear and it makes the complete opposite noise to cancel it out.” Flights are the perfect environment for using noise cancelling headphones.Source:AFP Sound processing technology in the headphones took care of that, Dr Bialkowski said, hence the requirement for a power source such as battery. Seasoned travellers often recommend investing in a set of good noise cancelling headphones and Dr Bialkowski said they were particularly good at cancelling out aircraft noise. “The kind of noise you really don’t want to hear on planes is that engine noise, that fan noise hum — it’s really repetitive,” he said. It’s all well and good to hear the theory behind noise cancelling headphones, but how well do they work in practice? A rather busy recent trip involving flights to Los Angeles,