The period corresponds to a frequency that we assign to the note D 5, which is in fact the note I was playing on my faithful Hohner Special 20. We saw in the example of the harmonica note that the time-domain waveform is periodic What musical note does this frequency come closest to? (See the text book on pageġ79 for the frequency of the notes of the tempered scale).What frequency does this period correspond to?.What is the period for one complete oscillation of the wave?.Using the information from the last paragraph: Of the pattern and the 9th is almost complete. Peaks for each iteration, one sharp and the other rounded. The upper peaks is easier because in the negative direction there are two different How many times does the pattern repeat in the 0.015 seconds plotted here? Be careful-counting There is a repeated pattern as a function of time.
Note the difference here compared to the dog bark. Whole waveform, instead, in the graph below, I plot a detail of a small piece of the Yes, it's just little old me playing a shaky note on the harmonica. Let's contrast this finding for the sound of the dog's bark with the recording ofĪ musical tone. There are a lot of peaks, however, the spacing between peaks along the time axisis not uniform. That there is no repeated patternin the waveform. In this expanded view (note how the time axis relates to the first figure above) weĬan see the real variations with time of the signal. Sound have musical qualities? To answer that let's first look more closely at a small The real quastion is, what is it that makes a Oh, I know around December we will get those records of Christmas Musicĭone by barking dogs, but that's just an aberration created in the warped minds of I think she is after milkbone residuals forĪ dog's bark is certainly a recognizable sound but you would not classify it as a The signal is clipped in the center, but my dog got disgusted with me and walked offīefore I could get a better recording. In seconds and the vertical axis is the amplitude of the digital signal. Here is a plot of the wave form that you've just heard. Listen to the sound, it should be readily Lets begin by considering the following sound. Sections we can also examine the properties of sounds in the frequency domain-theĮxtra insight given by examining the frequency spectrum is the basic objective of To accomplish these objective we will be listening to soundsĪnd examining their digitized wave forms in the time domain. IĪlso want to make a further distinction between two types of musical tone, so-called The purpose of this section is to distinguish between musical tones and sounds.
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