tritone

Your anxiety at the tritone is not just a culturally learned response - as the Wikipedia article you linked explains, the harmonic ratios in a tritone really are mathematically 'dissonant' when compared to, say, a perfect fifth or major third.

If you're working in C major, B to F looks like it's a fifth, but it's a tritone.

The augmented 4th (or diminished 5th - a.k.a tritone) perfectly splits the octave in this tuning system.

The beating/roughness couldn't have explained the dissonance of the tritone (C to F# for example).

That interval (B-F) would be the tritone, arguably the most dissonant one in the toolbox.

I'm guessing a real tritone would be far too anxious as a phone sound for most western ears.

For any mode, start with the mode's prototype on the white notes (eg D for dorian) plus its respective tritone and do the same.

The Coltrane Changes are very nice, but in the line of other jazz theory such as tritone substitution, the deceptive cadence, and so on.

C-F# tritone on the A and D strings, over open E bass.

I've been trained by Western music to think of the tritone as anxious or dissonant.

That's not decoration: the outer ring and inner ring are the same field read at a phase offset (looks like a tritone / minor-third rotation).

A lot of opinionated variations on chord spellings, too, with tritone subs sometimes included or not, 7b9s represented different ways, etc.

The "haunting" riff in the Hounds song features a tritone, and it's a modal-ish progression - perhaps with hints of folk music lurking in the background.

Whether its in the form of a V7->I cadence, which builds tension harmonically with a tritone that "wants" to resolve to the root.

The "chords" appear to be chosen as major or minor triads, with random inversions or random "common intervals" like octaves, fifths and fourths, I don't think I've ever come across a tritone or "wierd" intervals.