This feedback likely caused issues with the noise cancelling DSP. A little glue meant a $20 fix for a $400 pair of headphones.

In our Bose QuietComfort Headphones review, we said the QC Headphones take advantage of new DSP changes, resulting in deeper bass and more natural sound. Bose’s Active EQ is part of the QC ...

“The better the headphone fits a wider range of users ... hardware design with advanced digital signal processing [DSP]”, according to Bose’s Mark Bergeron. He gives one example: “Precise ...