heads, to obtain the same, or a multiple, of the AC frequency to achieve the same effect. For example, in the case of a guitar, the 6th (lowest pitched) string pressed to the third fret gives a G at 97.999 Hz. A slight adjustment can alter it to 100 Hz, exactly one octave above the alternating current frequency in Europe and most countries in Africa and Asia, 50 Hz. In most countries of the Americas—where the AC frequency is 60 Hz—altering A# on the fifth string, first fret from 116.54 Hz to 120 Hz produces a similar effect. Real-world example A Wikipedia user's Jackson Professional Soloist XL electric guitar has a nut-to-bridge distance (corresponding to above) of 25 in. and D'Addario XL Nickel-wound Super-light-gauge EXL-120 electric guitar strings with the following manufacturer specs: Given the above specs, what would the computed vibrational frequencies () of the above strings' fundamental harmonics be if the strings were strung at the tensions recommended by the manufacturer? To answer this, we can start with the formula in the preceding section, with : The linear density can be expressed in terms of the spatial (mass/volume) density via the relation , where is the radius of the string and is the diameter (aka thickness) in the table above: For purposes of computation, we can substitute for the tension above, via Newton's second law (Force = mass × acceleration), the expression , where is the mass that, at the Earth's surface, would have the equivalent weight corresponding to the tension values in the table above, as related through the standard acceleration due to gravity at the Earth's surface, cm/s2. (This substitution is convenient here since the string tensions provided by the manufacturer above are in pounds of force, which can be most conveniently converted to equivalent masses in kilograms via the familiar conversion factor 1 lb. = 453.59237 g.) The above formula then explicitly becomes: Using this formula to compute for string no. 1 above yields: Repeating this computation for all six strings results in the following frequencies. Shown next to each frequency is the musical note (in scientific pitch notation) in standard guitar tuning whose frequency is closest, confirming that stringing the above strings at the manufacturer-recommended tensions does indeed result in the standard pitches of a guitar: See also Fretted instruments Musical acoustics Vibrations of a circular drum Melde's experiment 3rd bridge (harmonic resonance based