I don't know, I don't use headphones with my pc. I would try to update the bluetooth drivers of the PC or a reset of the headphones and again pairing with the devices you want to use them with. However, I still have problems, randomly, with the connection to the Aukey BR-08 transmitter...

as mentioned here is the function to check or update the firmware

Sennheiser informed me that version 4.0.4 for android is out. This introduces the possibility to see, and eventually update, the firmware of the headphones (I did the update, but I haven't checked yet ...)

yet another update, we are now at 4.0.3 What’s new in Sennheiser Smart Control 4.0.3: - Fixed crash at startup (that I didn't have) - Performance optimization and bugfixes

In a few days 2 more App updates. From 4.0.0 we are now at 4.0.2. I still can't find the headset frimware, but they finally fixed a bug introduced with an update some time ago ... Bug that wasn't present before that update. In this post the description...

Has anyone updated the Sennheiser smart control app, for android, to the latest version 4.0.0? I can't find where the firmware of the headphones is indicated. On previous versions it was possible to see which firmware was installed. Thank you.

with AptxLL and aukey br-08 transmitter I don't have the reported problems. instead, after the latest M3 update, I must first connect the headphones to the mobile phone and then turn on the transmitter. If I open the headphones, with the Aukey transmitter ON, neither device connects. With the...

To exclude with certainty that the noise don't come from the source, If you haven't done so yet, try another device (perhaps a different brand).

Last night my M3s started to sound very bad. With Anc activated darker sound, much more bass, slight distortion at medium-high volume and sound more concentrated towards the center of the head! More distortion at maximum volume and incredible bass punch (more on the left side). This with Anc on...

Yes, after reading the suggestion, I wait before putting them on the head and, since then, it's working well

I know the calibration procedure and I redone it even after the upgrade. I didn't know it can be useful to wait 5 sec, every time I turn them back on, before putting them on the head. I'll try, thank you

I don't have these problems. However, since I updated to the latest firmware, it seems that the smart pause has become too sensitive... Watching a movie, sometimes, the audio goes away and comes back if I shake my head slightly

Never had any problems. Have you tried disabling and re-enabling the smart pause by following what the app suggests? (if I remember to wait at least 5 sec before wearing the headphones, after activating the smart pause , to allow calibration)

I hear a kind of white noise, barely perceptible if I'm not playing music and ONLY with ANC activated. I do not find it annoying because when the music is playing it is absolutely not noticeable and without music to realize that there is I have to turn off/turn on the ANC

I'm sorry, I don't use headphones with cable, but always in bluetooth with my smartphone or TV