Sep 26, 2017
@Wayne_M if you did check the firmware as low as 3.1.8 then why not allow to downgrade to 3.1.8 officially and settle the issue once and for all??
no one is asking Bose to do any further research on the issue supposedly resolved. All we are asking is to be able to downgrade to 3.1.8 which Bose claims has been tested as well.
Apr 30, 2019
Somehow I expected this answer, but then again not.
There is not just one test done by 3rd party testers who claim and show the difference. There are many, and at least 3 of them are more or less to be trusted.
See the links for reference.
As for me, call me stupid, but I owned the AE, and after the update the difference in high and low anc was gone! I did not know about issues reporting at this site, but right after the update, a lot more noice could be heard. Got new ones on returning, and now I have the AZ, on the 4.1.3. They’re not as good as my AE used to be, so I got me a Sony xm3. They’re great, but not as comfortable as the QC.
Looking on how Bose handled the issue, and how Bose communicated during this period is really a pity. I really have the feeling they wasted a great product. I would be happy to return the AZ and get a pair of AE running on firmware 2 or 3. Too bad this is not possible.
to me it is another disillusion to have trust in companies who in the end just care about money over quality.
Quoting the latest update: (after they corrected a flaw at ratings):
Update 08/22/2019: We've re-tested the noise isolation of the Bose QC35 II and the Bose Noise Cancelling Headphones 700after noticing a flaw in our testing methodology for both headsets. For the QC35II this means that while the 4.5.2 update did reduce a bit the noise cancellation performance of our unit but less than we had initially reported. This has changed the score, and the text has been adjusted to reflect this.
The ANC (active noise cancellation) of the Bose QC35 II is pretty good and within the ballpark the Noise Cancelling Headphones 700, but not quite as efficient as it use to be prior to the 4.5.2 update.
Apr 4, 2020
The report proves you went into significant effort to address your customer complaints - however, from an engineering point of view, two questions remain unanswered for me:
1. The measurements for NC performance were made with pink noise and you report just a dB value of NC. So, is this the average of NC performance across the whole spectrum (low to high freq.)? What if the SW update only impacts a certain part of the spectrum (e.g. middle frequencies) but this is "hidden" by averaging the NC performance across the whole spectrum? Why don't you show instead a graph of NC performance from low to high frequencies, for the same set of headset and for the SW versions 2.5.1, 3.1.8, 4.3.6 and 4.5.2?
2. Is the hardware of all QC 35II manufactured from 2017 till today the same? Any chance that different HW versions could be impacted differently by the SW update?
I don't believe myself to be a conspiracy theorist, but I was wearing the headset when I did the FW update from 2.5.1 to 3.1.8. The moment the update took place, I noticed a higher noise floor and a reduction in NC.
So, I have decided to risk it. Planning to upgrade(?) to 4.5.2 tomorrow. Would be keeping an eye on possible noise cancellation reduction. I have an AC running in the room, whose noise my QC 35 completely cuts-off with the noise cancellation set at high.
Other than that I am planning to play some pink/brown noise from the laptop speakers and see the noise cancellation before and after. If you have something extra to suggest/test, I don't mind being the guinea pig. Dearly hoping I wont regret this.
Mar 5, 2020
If you are happy with you QC's are strongly suggest you leave them be!
I too was curious and want to do a PhD on this, but wished I never touched or found the forum. I was very happy with what I had, whilst I have no evidence of changes I too feel they are less than they were.
Certainly there is no cabin pressure any more.
Feb 5, 2020
Strongly recommend against doing so. If the ANC degrades there's no going back and you'll be kicking yourself. No need to take one for the team.
Although this is a well written report and a lot of engineering resources went into its preparation, the conclusions don't match user experiences. Bose should have done more investigation to determine why. I'm still keeping my wife's pair at whatever FW version they're at and not risking a loss of ANC that I can't recover from.
Jan 10, 2020
Downgrade worked for me this morning anc is back for me maybe just got lucky but now my Bose SoundLink mini isn't working 1st generation done buying Bose. Flashing red light won't let me update it either.
Hmm. Seems the popular opinion is against messing with the firmware. I am very happy with the current firmware and I don't want to risk it yet. So I am standing down, probably will update to next version if the reviews are positive. Thanks a ton guys for helping me out
Jun 27, 2019
A complete and utter waste of time; downgrading has led to the same audible hiss, no difference between Low and High, and another nail in the coffin for Bose. Such a lousy, long time expected, ending for this sad and unfortunate story. Bose, you're a disappointment.
Dec 6, 2019
I was able to reach someone using the text message chat. It ultimately led me to a text chat with a human who offered to replace my headphones. I must note that I just purchased in November 2019, so well within warranty.