In Test Signals 1, 2, 3, 5, and 8, the right channel was 180° out of phase with the left; in the others (4, 6, 7, 9, and 10), the left and right channels were identical.

Could you hear any difference? I haven't taken the time to look it up yet, but my atrophied memory of physics & acoustics classes and the results of a college friend who ran a number of psychoacoustic experiments on anyone in the dorm who would agree to spend thirty minutes of listening to various progressively-annoying test tones* say that the human brain can't detect phase differences of identical frequencies.

You should, however, be very clearly able to hear the difference if you listen to the test signals through speakers. By and large the two channels will cancel each other out by the time they go directly from the speakers to your head, so rather than hearing sound coming from the speakers, you'll hear it bouncing off the walls. The reflected sounds coming to you from your environment are effectively an infinite number of sources of random phase, so the cancellation effect disappears once the sound spreads around the room and then comes back to you.

*he was largely testing for pitch and volume dominance, though. Spoiler: we tend to pay more attention to higher-pitched or louder tones.