Yorkieguy
Established Member
Most ear defenders are simply 'mufflers' and for the most part, work well enough.I used to use some £10 screwfix ones - they worked fine but were a nuisance to wear with safety glasses.
I recently got some isotunes Xtra 2.0. Link. Really pleased with them, would buy again if they broke!
However, given that the isotunes ones are battery powered, although their blurb doesn't say so, I imagine that they could be noise-cancelling ones, rather like noise cancelling headphones, which were originally created for airplane pilots to improve their comfort on long flights and are now widely used by music enthusiasts.
The technology, known as 'active noise-cancellation' (ANC), works by using microphones to pick up low-frequency noise and neutralise it before it reaches the ear. The headset generates a sound that’s phase-inverted by 180 degrees to the unwanted noise, resulting in the two sounds cancelling each other out. Same technology is used in industry to attenuate noise from machinery.
I have a pair of noise-cancelling ear defenders which have a built-in FM radio (which can be off or on). If I'm going to mow the lawn and put them on, I can still hear birds singing, but the moment I start the petrol lawn-mover, the noise cancelling kicks in. (They were given to me by someone who worked in a local factory).