[posterboy]

That's not how I understand the musical scale, if I even understood you correctly.

By relative interval I understand the interval within an octave, so C-D is a second regardless of the octave. The frequencies (notwithstanding fine tuning), double each octave. Of course the absolute difference is proportional to the power of two, depending on the octave.

The picture is different when counting the proportion relative a fundamental frequency of your choice. That's how dezibell is generally defined, arbitrarily over some reference point. This has two interesting consequences. When counting keys not modulo 8 but continuously, the ratio D5 over C5 is much lower than D4 over C4. Second, if you want integer multiples of the fundamental's wave length, the first multiple spans an octave, and only the fourth or fifth octave has a full scale--this chromatic scale worked reasonably well tested on AVR with a buzzer, except that F needed adjustment taken from a frequency table.

This means there can be no second in the lowest register unless you invert the programm and scale the higher octaves down linearly. In that case, the interference from the second (ca. 9/8'th of the fundamental's wave length) sounds extremely grating when played as a chord; the attenuation where the maxima of both waves meet forms the actual fundamental and your notes lie 9 to 8 above it, canceling each other out half the time; this is easier illustrated with a sixth that would be 1.5 of the base key. It is not a good illustration of music theory though, more like information theory while the signal chain is computationally intractable.

Jazz musicians, huh

[bradrn]

> By relative interval I understand the interval within an octave, so C-D is a second regardless of the octave.

I don’t think GP is denying this. They are simply saying that an interval at a lower frequency is generally more dissonant than the same interval at a higher frequency.

[posterboy]

I was conceeding to make sure I understood them correctly.

The problem is, if you have only two tones, the lower one is essentially the base frequency in my address. But I'm assuming you have somewhat of a natural buzz, or resonant frequencies from the environment that command the base frequency for you, so you can't take any two intervals and compare them as if they were relatively same. This should be relevant especially if you play them one after another to compare, no?

[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.