When mixing harmonically using the Camelot notation system, harmonic mixes include going from nA -> nB, or nA -> (n+1)A or (n-1)A.

What other intervals are known to be 'acceptable'? I've seen a passing reference to something like +7 or so, but my music theory is too rusty to understand why this is.

I'm more interested in the intervals (+1, +7, etc.) that sound harmonic, but if anyone wishes to share some enlightenment on the music theory aspect, it is welcome as well.

my personal opionion is learn to trust your ears over any harmonics system...even if you dont know music theory as a dj your ears can tell you if the mix will work or not. but to answer your question you can also do half-steps up or down in key which kind of changes the sound but if done with the right tracks can lift the air in the crowd quite a bit.
i think in the camelot system its a modulation mix??

I agree. I tried to mixing harmonically (labeled all my tracks!!) and found no difference because I do it without even realising. Your ears always know better

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+1 -1, +4, -3, +7.

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Thanks for all the input. I understand that your own perceptions (through your ears) are always the best determining factor, but I still wanted to know the intervals that are known to not collide.

I suppose a better phrasing of the question would be to to find the intervals that don't work.

Small steps at first, then work from there. =)