[adzm]

You can actually hear the beat frequencies like tuning a guitar. So intervals like the fifth or an octave are definitely 'in tune' when you try it. Interestingly if you play a pure sine in each ear with one slightly detuned, your brain will also hear the beat frequencies as if the waves were interfering despite each ear getting separate pure signals! There was even an open source program Gnaural for experimenting with this effect - binaural beats.

[dahart]

I can’t hear a beat frequency against my tinnitus tones, and I really wish I could. (I’ve tuned my guitar with beat frequencies for decades.) The tinnitus tones are very elusive when I try to pin them down with a sine wave, but I can get close by alternating a sine wave on and off while I vary the frequency... the memory of the tone from a second ago has been more reliable than trying to hear if they’re close when overlapping.