Chapter 1. Physical Sound
1.5 Frequencies and Instruments
(the full color chart is available as bonus content with the purchase of the PDF version of the book!)
The first line (Notes) indicates the name of the note as referenced from a standard piano keyboard with 88 notes: C1 is the first C note all the way to the left of keyboard; C4 is the middle C.
The second line displays the corresponding frequencies in Hz.
Each frequency range (called Type in the figure, displayed on the fifth line) has both negative (third line) and positive (fourth line) connotations, depending on context and taste; descriptions are what they are, understand what you can J
The last line displays the full spectrum of human hearing (called Standard audible range) from 20 Hz to 20 kHz. You can test your own limits here; my upper limit is 14 kHz which is somewhat low.
Dark gray covers the instruments’ main frequencies, while light gray is for overtones. Instrument names are displayed more or less in the middle of their frequency range: 240 Hz for male vocals, 450 Hz for female vocals.
The standard tuning note is Standard A, at 440 Hz, which corresponds to the middle of the range for pianos and female vocals. Coincidence?
Note that trained ears can hear a difference in pitch (frequency) of a note of 1-2 cents; a cent is 1% of the difference between 2 adjacent semitones. If you hear someone saying “She is off by a couple of cents”, they mean that the singer’s note is off pitch by 2% in the frequency range of that semitone; if she is singing a standard A at 440 Hz, 2% is 8.8 Hz; if she is singing a high A at 880 Hz, she is 17.6 Hz off. You can test your own sensitivity here; I am 90% for 5 cents at 440 Hz, which is decent.
Many of the instruments on the chart have their middle range below 1 kHz; however, much of the magic in making music happens way beyond that frequency – try to use a low pass filter with a cutoff frequency of 1 kHz and you will see why.
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