8 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
Live 770NC fails to power on after ~3 months of use
Owner reports the unit would not power on after three months; charging overnight and hard reset attempts did not help initially, then it resumed working after being left plugged in for days, suggesting a firmware/software power state fault rather than a dead battery.
What to check. If you buy this model, be aware of a reported failure to power on after a few months of use. A hard reset may not recover it immediately; leaving it charged for an extended period appeared to revive it in this case. This is a single owner report, not a widespread documented pattern.
ANC produces crackling/popping sound with head movement
Two separate owners report that the ANC produces a crackling/popping sound when moving, linked to a loose fit on larger heads.
What to check. If you have a larger head or the headphones don't fit snugly, the ANC may produce crackling/popping sounds during movement. This was severe enough for one owner to return the product.
An owner reports receiving the unit defective with the left earpiece beeping and buzzing.
What to check. A defective left driver that beeps and buzzes is a unit-level fault that typically requires a return/exchange rather than a user fix. Buyers should test both ear cups promptly on arrival to catch it within the return window.
An owner reports receiving a defective unit where the left earpiece beeps and buzzes, indicating a driver or wiring fault in the left earcup.
What to check. Check the left earcup for beeping/buzzing sounds on arrival. If present, this indicates a defective driver or wiring and should be returned under warranty immediately.
An owner reports crackling/popping from the ANC when moving, tied to a loose fit.
What to check. ANC-induced crackling/popping on movement is a behavior some owners hit, often linked to fit/leak rather than a hard fault. It is low severity but worth checking if you move a lot while ANC is on; a snug fit may reduce it.
An owner reports gesture controls did not work well. An Amazon.de reviewer similarly notes 'the touch controls can be a little finicky at times'.
What to check. Touch/gesture controls may be unreliable or finicky. This is an annoyance rather than a hardware failure, but may affect daily usability.
An owner reports the wear detection (auto-pause) works only sporadically. An Alza.hu reviewer similarly notes 'auto pause is unusable if you have a hood - off'.
What to check. The auto-pause/wear detection feature may be unreliable, especially with hoods or when repositioning the headphones. This is a firmware/sensor quirk rather than a physical failure.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Over-ear noise-cancelling headphones catalog, version 0.1.1, under the CC-BY-SA-4.0 license.
