Calculate acoustic resonance

Yes, lookup the velocity of sound in the object's material. You can calculate the resonant frequency from the velocity divided by the object's size. If sound can find different path lengths through your object, to reflecting surfaces, it can form multiple resonant modes. Sound reflections occur wherever there's an acoustic impedance change.

--- Oops... Yes.

V f = --------- 2 (lE3)

Where f is the resonant frequency of the object in the length direction, in Hertz, V is the velocity of sound in the medium the object is made from, in meters per second, and l is the length of the object in millimeters.

-- John Fields Professional Circuit Designer

No...The resonance of a physical object is not a simple function of the length. Resonance involves the length, width, general size and shape, mass and modulus of elasticity. It also involves temperature and the specifics of how it is held or constrained. Furthermore in most objects, there are many modes of vibration so that no one simple frequency occurs. Such is the case with bells, for example, the multiple modes causing richness in tone. However, there are simple equations for well defined objects like steel rods held at the specific ways or wires under tension. If you ask a specific question about a specific object, maybe we can find an equation. Bob

"John Fields" schreef in bericht news: snipped-for-privacy@4ax.com...

Does this apply to piano wire too?

If it did, all solid strings of identical material would have the same resonant frequency, regardless of thickness, and pianos don't work that way. The equation is for compression wave propagation, whereas most acoustic effects are from bending modes, and strings involve tension as well, all of which are far more complex.

Your original "no" is closest to the truth in practical acoustic situations.

John

The fundamental wavelength for strings is twice the string length, since both ends are nodes. The formula is sqrt( T / mu ) / ( 2L ), where L is length (m), T is tension (N), and mu is mass density (mass (kg) / length(m)), which accounts for the thickness of the string. If a string were a perfect one-dimensional line, vibrating in a vacuum, the formula would be exact, but...

-- john