Originally Posted by IO540
OTOH, the £300 Bose ANR headsets which are sold at Dixons etc for airline passenger wear seem to be a lot worse - based on my test of one of these. It got sent back.
No surprise there. The airline passenger headset has to be optimised for an airliner cabin, in which noise is of higher pitch than in a piston-engined aeroplane, and has no need for low-frequency attenuation. Horses for courses.
The Bose-X appears to be an allrounder, though - it works as well as (actually a bit better) than the passenger headset in an airliner cabin.
What perhaps amazes me most with the Boses is the VERY noticeable drop in fatigue after long flights. You simply don't feel worn out after 5 or 6 hours in the cockpit. And no ringing ears either
ANR works very well for lower frequencies and less so for higher frequencies. By low I mean 50-500 Hz. Above that an ANR headset is just any other passive headset. This is ideal for prop aircraft (2-blade prop pulse: 80 Hz, 3-blade prop pulse - 120 Hz, all at 2400 RPM, 4 cylinder firing/exhaust pulse: 80 Hz).
Passive attenuation works better at higher frequencies.
Bose's give up some passive attenuation to give you more comfort - they have noticably lower clamping pressure than most other headsets.
An "old design" good passive headset with an ANR cicruit added can be quieter than the Bose, but it still squeezes your head like a vise.
If you consider buying a headset in that price range, I would recommend to get them and wear them for several
hours at a time. Otherwise you will not appreciate the difference. The Boses are not neccessarily the quietest anymore, but they are very quiet and very comfortable.
When you borrow some from a friend, check if it has the sheepskin cushion on the headband, not the old foam ones. These could give you a headache after an hour or so because they can create point pressure unless you wear the headset at a perfect angle - the only real flaw the 1st generation Bose-X had.