help with sound?

Question

does anyone know the answers to these?

Given a fundamental of 125 Hz which of the following set of frequencies (from the sound spectrum) will most likely add to a strong sense of musical pitch in the fundamental?
a. 200 Hz
b. 500 Hz
c. 400 Hz
d. 250 Hz

Given a fundamental of 125 Hz, which of the following set of frequencies (from the sound spectrum) will most likely detract from a strong sense of musical pitch in the fundamental?
a. 250 Hz
b. 500 Hz
c. 375 Hz
d. 200 Hz

Answer 1

1. Any integer multiple of 125 Hz.
2. Any non-integer multiple of 125 Hz.
Those are the definite rules. In addition a sort of subjective rule of thumb says that a small integer ratio multiplier may add something to the sense of pitch, but this shouldn't be stretched too far or you get into discord. Ratios generally considered harmonious are minor third (~6/5), major third (~5/4), and major fifth (~3/2). Oddly 4/3 (a major fourth) doesn't seem so much to help to the lower note as to dominate the apparent pitch with help from the lower note. So ~150, 156 and 187 Hz would be acceptable.