Analysis of sound with smartphones A) 1) -­‐We will sound from a smartphone an instrument. -­‐ Using spectrumAnalyse, F1 is the fundamental mark, and then there is the frequency corresponding to the pitch. On android On IOS : Piano
536 Hz
2) -­‐ The same note transmitting from a smartphone from 2 different instruments. Using spectrumAnalyse, F1 is the fundamental tagging of each instrument, there is then the frequency corresponding to the pitch of each instrument. On android (mi=E) 660 Hz
660 Hz
On IOS : 3) -­‐ It emits a sound from a smartphone an instrument. -­‐ Using spectrumAnalyse, the fundamental frequency F1 are identified and harmonics and is denoted by their frequencies. -­‐On Calculated for F2 = 2 * F1 and do the same for all harmonics On Android : We see that 1050 ≈ 2* 520 so F2 = 2* F1 On IOS (with F3= 3.F1) 520 Hz
1050 Hz
4)-­‐ The same note transmitting from a smartphone from 2 different instruments. For each instrument, using spectrumAnalyse, we identify the harmonic number and the amplitude of the harmonics. Then comparing. On Android : (it will be the same on IOS) We can see that the same note of two different instruments have the same pitch but not the same number of harmonic and an amplitude and a different transient, they sound different and therefore a different timbre. 5) -­‐ It emits different notes separated by an octave from a smartphone (in our case, the C 5 and C 6) -­‐ Using spectrumAnalyse, we identify the fundamental frequency of each note -­‐ Calculate the ratio between the two frequencies found previously and check that it is equal to 2, which means that the notes are separated by an octave. (Do=C) F1= 516 Hz F1=1050 Hz The value C6 / C5 = 1050/516 = 2.03. It is clear that the musical interval is 2 and thus the notes are separated by one octave. See for IOS 6) -­‐ It emits two consecutive notes from a smartphone (in our case, the C and C#) -­‐A Using spectrumAnalyse, we identify the fundamental frequency of each note -­‐On Checks that f (C #) = f (C) * 2 ^ (1/12) F1= 515Hz F1= 548 Hz F(C)= 515 Hz F(C#) = 548 Hz F(C)*2^1/12 = 515*2^1/12 = 545 Hz = F(C#) We checked that f(C#) = f(C) *2 ^(1/12). Here on IOS with B# ; f(B#)= 494,1Hz the report f(c)/F(B#)= 2^(1/12). C) 1) In the same note, the frequency of the sound does not depend on the instrument. Cf. question) 2 2) A pure tone has a single frequency and therefore no harmonics. The recording obtained is a spectrum containing a peak which corresponds to the fundamental frequency F1. A complex sound has a plurality of frequencies that is a fundamental and its harmonics. The recording obtained is a spectrum containing several peaks which correspond to these frequencies. 3) A quantity related to the pitch of a sound is the frequency in Hertz (Hz). 4) The tone (timbre) of an instrument depends on harmonics (number and amplitude).