The document discusses frequency and phase in sound and audio engineering. It defines frequency as the pitch of a sound, measured in Hertz (Hz). The range of human hearing is between 20 Hz to 20 kHz, with lows between 20-250 Hz, mids between 250 Hz to 6 kHz, and highs between 5 kHz to 20 kHz. Frequency response refers to the range in which a signal can be produced uniformly and without distortion by a system. Phase is defined as the relative delay between two sound waves of the same frequency, and being in or out of phase can increase or decrease the amplitude and loudness of a wave.

1. Frequency and Phase
Sound and Audio Engineering

2. Frequency
• Frequency: what we perceive as the pitch of a
sound. Frequency is measured in Hertz. The
faster the rate, the higher the frequency.
• Hertz (Hz): cycles per second (measurement of
frequency).

4. The Range of Human Hearing
• Range of Human Hearing: the frequencies that
humans are capable of perceiving, or hearing
– 20 Hz to 20 kHz (20,000 Hz)
– Most people don’t hear more than 16kHz, gets
worse the older you get.
• LOWS (Bass Frequencies): 20Hz – 250Hz
• MIDS: 250Hz – 6kHz (6,000Hz)
• HIGHS (Treble Frequencies): 5kHz – 20kHz
(5,000Hz – 20,000Hz)

6. Frequency Response
• Range in which a uniform, undistorted signal
can be produced.
• Sensitivity to different frequencies varies in…
– People
– Microphones
– Speakers

7. Phase
• The relative delay, or offset, between 2 sound
waves of the same frequency

8. • What the image in the previous slide represents
is that when sound waves with the same
frequency are in phase, the amplitude and
subsequent loudness of the wave are increased,
while when they are out of phase the amplitude
and loudness of the wave are decreased.
• Why might this be important to keep in mind
when using multiple microphones to record one
instrument?