Noise cancellation not working QC35 II
I bought a secondhand pair of these headphones on eBay and they seem in great condition but the noise cancellation doesn’t work at all. Pressing the button tells me it’s on or low or off but makes no difference to the headphones. I also tried downloading the app last night and controlling from that to no effect. Are they likely dud? Or is there some other trick I may be missing to activate the noise cancellation? Also, what should it “sound” like when activated?