not really a lot of broken promises

I thought it was too good to be true when I heard of this helmet: Finally an inexpensive headset, bluetooth with noise, good battery life, good sound, buttons on the headset to control the transmitting device . Alas, most of the core functions I found defects to the point that I sent to Amazon after a trial week.

Let's start with some positives:

-very good bass well defined and without slamming invasive
-its remarkably detailed, whereas Bluetooth headsets are not known for it
-buttons convenient to pause music, answer the phone, etc ...
-aspect robust and well finished
-The weight is not no feeling
-l'autonomie is excellent

and now the negatives (some prohibitive for me):

passive -l'isolation is good but the noise canceling function is inherently poor: the extra bass are noticeable, I think including the noise of traffic on the boulevard in front of my house. Worse, as other frequencies are filtered well enough, these serious look accentuated, and to make matters worse, the slightest movement of the body, cavernous resonances occur in the atria, unpleasant. Certainly, it is less noticeable when listening to music.
Sometimes for hours with noise canceling function activated, unpleasant hissing in the left atrium (defective helmet?). Even the noise of my old JVC HA NC250 was better despite a poor passive isolation.
-The Bluetooth connection produces breaks in the sound, especially bothersome crunches they are very common! It happened with both my iMac and my Android phone.
-The sound is flattering, but few faithful, especially with the active noise .... not too much to complain about the bass enhancement, but the highs are aggressive, not good for the hearing, it must be remembered ? Mediums are too recessed for my taste, in fact, it depends on the music.

I found a used Bose QC25, paid more than the Plantronics, but it was worth it, despite the lack of bluetooth: finally an impressive noise reduction, and sound which, if not no more detailed, much more balanced and versatile on the issue of musical styles or recording qualities.