I don't know... chant musics are frequently
intended to bring on a trance in the listener. Chants are used in
the ritualistic events that underpin certain cultures, traditions,
religions, etc.
I've been brought to places while in a deep focus (aided by chant
musics) that parallel experiences I've had on psychoactive drugs.
In that sense, Eno's description is sort of perfect to me.
Gregorian chant was used to induce religious focus, so the music
itself does sort of fall out of primary consideration when "used"
correctly.
Eno absolutely meant "ignorable" in the normal dictionary way. He did not mean "trance-inducing", or "religiously focused". Eno's coinage had absolutely nothing to with "inducing" anything.
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Eno remembers the event somewhat differently. “After she had gone, and
with considerable difficulty, I put on the record,” he recalls. “After I
had lain down, I realised that the amplifier was set at an extremely
low level, and that one channel of the stereo had failed completely.
Since I hadn’t the energy to get up and improve matters, the record
played on almost inaudibly. This presented what was for me a new way of
hearing music – as part of the ambience of the environment just as the
colour of the light and sound of the rain were parts of the ambience.”
[ ... ]
All this sounds like a recipe for boredom, and for many people that’s
exactly the result when they listen to Music for Airports. For others,
the fact that the music is so quiet and so content to circulate such
thin little scraps is the secret of its appeal. Eno himself describes
the album as being “as ignorable as it is interesting”.
[ and may the universe not react to harshly to me citing the Daily Telegraph ]