harmonics ???

Question

i work in building maintanance. the other day i was in a pit turning off a water valve from the city water suply. the pit was about 6 by 10 with a manhole entrance. i had a song stuck in my head and was humming it at the time. as i was humming i noticed a few note seemed louder i was woundering if the notes pitch was from the size of the pit or if it was from the concreat the pit was made out of?

i have an advance knowledge of music

there where a few note. one of the others i think was a major fifth. could it be something to do with over tones???

there where a few note. one of the others i think was a major fifth. could it be something to do with over tones???

Answer 1

Positive and negative interference... If the distance from your mouth to the pit wall was a perfect multiple of the wavelength of the pitch there would be positive interference and the Sound could increase....
Yes. it would not work for all frequency but there is a minor minor chance it would work.
Science in life!! Good on you.. Keep it up... This is the sort of stuff that gives us gravity from falling apples...

Answer 2

The previous poster is correct. You were humming in a resonant chamber. It was the size of the pit--in resonance, the waves bounce off the walls and come back in just the right phase to add to the new waves coming out of your mouth. The travel time is basically the same for all the notes, so what matters is the wavelength and how it compares to the dimensions of the space you were in. Rooms of different size and shape will resonate with different notes.

Just as you can fit harmonics on a guitar string, you can get harmonics in any resonant system. So I would not be surprised
if you picked up thirds or fifths. The specific overtones you generate depend on the specifics of the chamber and how you "play" it--just like a violin. Perhaps the specific properties of the concrete had some effect--just as the specific wood in a Stradivarius has its signature.

Answer 3

If you were humming by yourself with no additional voices or music playing, it made no difference whether is was a major 5th or not. What you probably experienced was harmonic vibrations relative to the size of the concrete pit. The concrete pit reflects the sound waves, and some tones may have fit the harmonics of the pit increasing the apparent "loudness" of the notes. It is also possible that certain tones in that confined area resonated at a pitch that matched the harmonics of your hearing mechanism.

Love, Hope, & Peace,

Cal-el & Swissy

Answer 4

Concrete is very reflective of sound, so you were indeed in a resonant chamber. You were humming in an organ pipe, but not one designed for a single frequency. If you don't have perfect pitch, you'll find yourself unconsciously changing the pitch of your humming to match the resonance of your concert hall. Call it "singing in the shower, on steroids"!

Answer 5

Ah yes the water in the bottle type harmonic AKA flute.You may have tried to acquire several bottle with each bottle containing different amount of water and blow thru each bottle to produce different music note or sound.The pit that you went into is similar to the water bottle that I had just describe to you.

Answer 6

the pitch was one the surrounding materials was less likely to absorb ( the proper term is FREQUENCY but with your advanced knowledge of music and all ...)