Originally Posted by Impulse I wouldn't call the M-80 semi open or poor at isolation... The cups are slightly vented, and there are some on ears that isolate more (most of those clamp way harder too, e.g. Senn HD25-1 II), but there are way more with poorer isolation.
For me it's just the right amount of isolation, enough that I don't hear people speaking near me or the general background noise of a mall/airport, but not so much that I'll miss an important PA announcement or someone trying to get my attention (though I still have to pause the music to understand anything).
If I want to be completely oblivious to the world I'll grab my IEM, and honestly, no headphone is gonna come close to the more isolating IEM in that regard.
This is the best description of the level of isolation of the M80 you can read. I second it word by word, especially the statement about being "just the right amount of isolation" for exactly the same reasons.
But I thought that for benefit of anyone searching for "M80", "isolation" and "plane", it would be worth adding a note of warning.
I have only found a place in which this level of isolation is not enough for a satisfactory listening: a flying plane. The isolation (or lack of) seems not equally distributed through the spectrum, and higher frequencies pass better than bass. So the kind of continuous white noise coming from the wind and engines was still too prominent, drawning the already not-that-so-prominent highs that the M80 produce, totally ruining a quality listening experience.
I would strongly recommend against the M80 on a plane, even if I immensely enjoy them elsewhere. Knowing what they are capable of, the contrast is so painful. If anyone is thinking on them as a option where one of the primary uses will be flying, my advice is to look elsewhere. For any other primary use they are a _very_ strong contender, but not for this one.
I have not tried any of the usual contenders on the same tier (HD25-1 II, DT1350) in flying. But I would bet that, even if we find that the M80 really perform worse than them on that environment, none of them really matches the clean listening experience than an active noise cancelling headset can provide. Even if they perhaps don't sound as damned good as the M80 in favorable conditions, on the plane wind and engines mask this to the point to which a somewhat not-so-perfect sound that you _can_ hear will always beat any glorious sound drown behind the 'smoke' of background noise.
Before anyone jumps in and says the he has been very happy in a plane with the M80, let me acknowledge that perhaps not all planes and engines (and ears, and volume levels) sound equal. I can only talk by my own personal experience in a Boeing 767, which seems to be a notably noisy plane to the point of being banned from some airports just because of noise peaks on take off and landing. But at the same time is a very common model for long range trips where you have to be there for over 10 hours, just where you will regret more not being able to properly enjoy your music for so long.