Quizz 1 Flashcards
Bosh
Definition of Frequency:
The number of pressure cycles (high-low pressure) that occur per second. Measured in Hertz (Hz).
Frequency and Pitch Relationship:
Higher frequency corresponds to higher pitch.
Average Threshold of Human Hearing
Around 1-1.5 kHz.
Just Perceptible Change in Level:
The smallest change in sound level detectable by humans is around 1 dB.
Sound Pressure Measurement:
Measured in Pascals for pressure, but commonly expressed in decibels (dB) as a ratio relative to the threshold of hearing.
Threshold of Pain in db
Around 120-130 dB.
Human Hearing Range:
Audible sound for humans consists of pressure variations between 20 Hz and 20 kHz.
Directional Hearing:
The brain processes slight differences in time and amplitude between the two ears to perceive sound direction (using Pinna and Cochlea).
Pinna Function
Directs sound into the ear canal and toward the eardrum
Tympanic Membrane (Eardrum)
Vibrates with sound and transmits vibrations through the ossicles in the middle ear.
Ossicles
Consist of the Malleus, Incus, and Stapes, transmitting sound from the eardrum to the inner ear.
Cochlea
Part of the inner ear where vibrations are turned into nerve signals.
Basilar Membrane:
A membrane in the cochlea that vibrates at different places for different frequencies, helping to process sound.
Phonogram Invention
By Thomas Edison, saw widespread use from 1877 to 1925.
Magnetic Tape Invention
Developed by Fritz Pfleumer, it allowed for increased bandwidth and longer recording times compared to earlier recording methods.
Vinyl Records rotate at what rpm
Rotate at 33 or 45 rpm.
A 300Hz vertical cut
in vinyl typically results in phase cancellation between the left and right channels.
DAC (Digital to Analogue Converter)
Converts digital signals into analogue for playback (e.g., speakers).
Sample Rate
The number of digital samples per second, with common rates being 44.1kHz, 48kHz, etc. Higher rates capture higher frequencies.
Nyquist Frequency
The highest frequency that can be sampled accurately, typically half the sample rate.
Headroom
Refers to the dynamic range available before clipping or distortion occurs.
Uncompressed Audio Formats:
WAV, AIFF
Lossy Compressed Audio Formats:
MP3, AAC
Distortion
Any unwanted addition or subtraction to the signal, such as harmonic distortion or clipping. Digital recordings can clip if pushed beyond 0dB but cannot be fixed easily.
Clipping
Digital clipping occurs when the signal exceeds the available dynamic range, often irreversible.
Fritz Pfleumer invented
Invented magnetic tape, which enhanced audio recording quality and flexibility.
Technological Advancements: in audio the introduction of:
The introduction of CDs and computers played a pivotal role in modern audio recording, providing increased fidelity and storage capacity.
what’s timbre
In music, the perceived musical sound quality of a note is its timbre.
Timbre is the difference between hearing music or just noise.
whats Amplitude
The height of a sound wave measured from the rest position to the
crest of the wave is called amplitude. The taller a sound wave is, the
louder the sound is heard.
Wave Speed
How quickly energy is passed from molecule to molecule
determines the wave speed of sound. Sound travels at dierent
speeds through dierent materials depending on the arrangement of
molecules
Wavelength
The wavelength of a sound is the measurable distance between two
waves.
Wave Direction
Sound waves propagate (move) outwards in all directions from the
source of the sound. The direction of the wave can be changed
through reection, like an echo.
