[mrob]

I think it's likely to be less dissonant at lower frequencies. Try a 51.913Hz sine wave (G#1) played with a 55.000Hz sine wave (A1), at low enough volume that they don't clip when added together. This does not sound dissonant to me. Then speed them up by 16x (increasing the pitch four octaves). This does sound dissonant to me, although not extremely so, because timbre makes a huge difference, and sine waves produce the least dissonance of all timbres.

I don't have a bass guitar, but if somebody does they might want to try playing those G# and A notes together, and check how consonant they sound with the tone knob turned all the way up and all the way down. I predict that the brighter tone will sound more dissonant.