A violinist freind hears phantom notes unrelated to the played chords when she plays the violin and..?

Question

another plays the flute. These phantom notes are like low humming and have vibrato. Is there something going on with harmonics or beat notes or something? Has anyone else heard them?

Answer 1

These can also be called difference tones. I am a professional flutist and teacher. When I play duets with a student, and I am playing a note that vibrates at 1000 cycles per second, and she is playing one at 800 cycles, per second, then the humming note is the *difference* - 200 cycles per second. These can be used for learning. I have student play scales with me, in thirds. We invert each interval. If the DIFFERENCE note stays exactly in tune, then we are, also. If the note migrates, then at least one of us is slightly unstable in pitch.

Answer 2

Not part of the overtone series, since they sound *lower* than the played notes. They are, if you will, "undertones" that are formed by the combinations of the two frequencies.

The beats from each frequency form an interference pattern that has its own beat, or frequency. Some call it an interference wave. Others call it "aliasing". If the math involved (not my strong suit) comes up with a frequency of 25 Hz or more, (the approximate lower limit of human hearing),we hear a low "combination" tone.

The only analog I can come up with is from the movies -- when you see, let's say, a wagon wheel turning in an old west movie, you may have noticed that it appears to change directions and go backwards. That is because the frequency of the wheel's rotation "disagrees" with the shutter speed of the camera, and so we see a successive series of frames catching the wheel at the "wrong" point in its rotation.

Does that make sense?

Mamianka below has terminology that is more correct than mine. Here is a link:

http://en.wikipedia.org/wiki/Combination_tone

Answer 3

Could they be part of the overtone series? I often hear them emitting from the piano or elsewhere when I sing.

Another possibility could be some sort physiological anomaly in the ear...

Answer 4

I don't know anything about flute, but I do know with stringed instruments, these might be "wolf tones."

See the Wikipedia article:
http://en.wikipedia.org/wiki/Wolf_tone

Answer 5

No, cuz if you do not know tips on how to play one, you would simply humiliate your self. Whereas I, alternatively, do not make a idiot of myself. Volume does not make you a greater participant, talent does. And train.