Sound and listening: Difference between revisions
Andre Castro (talk | contribs) No edit summary |
|||
| (4 intermediate revisions by one other user not shown) | |||
| Line 1: | Line 1: | ||
=What is sound= | =What is sound= | ||
| Line 7: | Line 4: | ||
We experience sound thought displacement of air molecules from a source to a the receiver. | We experience sound thought displacement of air molecules from a source to a the receiver. | ||
[[File:source-receiver.gif]] | [[File:source-receiver.gif|400px]] | ||
When a source emits a sound, it makes the air molecules compress and decompress, traveling away from the source. | When a source emits a sound, it makes the air molecules compress and decompress, traveling away from the source. | ||
| Line 13: | Line 10: | ||
The rate of this compression-decompression variation is what is called the ''frequency'' of a sound. And the amount of air molecules displace give us the ''amplitude'' or ''volume'' of a sound. | The rate of this compression-decompression variation is what is called the ''frequency'' of a sound. And the amount of air molecules displace give us the ''amplitude'' or ''volume'' of a sound. | ||
[[File:sound-compressdecompress.gif]] | [[File:sound-compressdecompress.gif|400px]] | ||
==Sound wave properties== | ==Sound wave properties== | ||
[[File:soundwave-properties.jpg]] | [[File:soundwave-properties.jpg|400px]] | ||
* frequency <nowiki>=</nowiki> pitch | * frequency <nowiki>=</nowiki> pitch | ||
| Line 23: | Line 20: | ||
** measured in decibel (db) | ** measured in decibel (db) | ||
[[File:wave-amp-freq.png]] | [[File:wave-amp-freq.png|400px]] | ||
'''Sound waves on liquid''' | '''Sound waves on liquid''' | ||
| Line 30: | Line 27: | ||
Human audible sound, or the hearing spectrum, is located between 20Hz and 20 000Hz of of the acoustic spectrum | Human audible sound, or the hearing spectrum, is located between 20Hz and 20 000Hz of of the acoustic spectrum | ||
[[File:audio_spectrum.jpg]] | [[File:audio_spectrum.jpg|400px]] | ||
| Line 37: | Line 34: | ||
How does the movement of air molecules gets perceived as sound? | How does the movement of air molecules gets perceived as sound? | ||
[[File:ear.jpg]] | [[File:ear.jpg|400px]] | ||
==Spacial Perception Sound== | ==Spacial Perception Sound== | ||
| Line 46: | Line 43: | ||
* filtering, by the outer ear | * filtering, by the outer ear | ||
[[File:spacialsound.jpg]] | [[File:spacialsound.jpg|400px]] | ||
'''Janet Cardiff - binaural mics''' | '''[[Janet Cardiff]] - binaural mics''' | ||
=Hearing as composing= | =Hearing as composing= | ||
| Line 60: | Line 57: | ||
4'33'' (1952) is a probably the most famous John Cage composition, where the performance stands in front of the audience without playing a single note, for 4 minutes and 33 seconds. | 4'33'' (1952) is a probably the most famous John Cage composition, where the performance stands in front of the audience without playing a single note, for 4 minutes and 33 seconds. | ||
[[File:Cage_433_1-640-TITLE.jpg]] | [[File:Cage_433_1-640-TITLE.jpg|400px]] | ||
http://hyperallergic.com/85779/the-original-john-cage-433-in-proportional-notation-19521953/ | http://hyperallergic.com/85779/the-original-john-cage-433-in-proportional-notation-19521953/ | ||
| Line 77: | Line 74: | ||
* http://www.getty.edu/research/tools/guides_bibliographies/david_tudor/av/rainforest.html | * http://www.getty.edu/research/tools/guides_bibliographies/david_tudor/av/rainforest.html | ||
* Holzer, Derek, and Mads BEch Paulszewski. n.d. “Rainforest 2012.” http://macumbista.net/files/rainforest_overview.pdf | * Holzer, Derek, and Mads BEch Paulszewski. n.d. “Rainforest 2012.” http://macumbista.net/files/rainforest_overview.pdf | ||
[[File:Rainforest1.jpg|500px]] | |||
[[File:tudor.jpg|500px]] | |||
==Electromagnetic pickups== | ==Electromagnetic pickups== | ||
| Line 90: | Line 88: | ||
* https://www.youtube.com/watch?v=5tCphr8pbFk | * https://www.youtube.com/watch?v=5tCphr8pbFk | ||
=Digital audio= | =Digital audio= | ||
Analog audio is stored in a continuous analogue to its source. | Analog audio is stored in a continuous analogue to its source. | ||
[[File:record-grooves.jpg]] | [[File:record-grooves.jpg|400px]] | ||
http://www.synthgear.com/2014/audio-gear/record-grooves-electron-microscope | http://www.synthgear.com/2014/audio-gear/record-grooves-electron-microscope | ||
| Line 104: | Line 101: | ||
Digital audio on the other hand is stored '''discretely''' (in segments or samples). | Digital audio on the other hand is stored '''discretely''' (in segments or samples). | ||
[[File:signal-representions.png]] | [[File:signal-representions.png|400px]] | ||
==sampling rate and bit rate== | ==sampling rate and bit rate== | ||
| Line 110: | Line 107: | ||
'''sampling rate''': how frequently the analogue signal is sampled | '''sampling rate''': how frequently the analogue signal is sampled | ||
[[File:discrete-signal.png]] | [[File:discrete-signal.png|400px]] | ||
[[File:discretesampling.png|500px]] | [[File:discretesampling.png|500px]] | ||
| Line 119: | Line 116: | ||
'''bit rate''': accuracy of sampling - how many values are used to represent the amplitude of a signal | '''bit rate''': accuracy of sampling - how many values are used to represent the amplitude of a signal | ||
[[File:bit_depth.png]] | [[File:bit_depth.png|400px]] | ||
* The bit rate of a CD is 16-bit: 2¹⁶ (65536) values are used to encode the audio digitally | * The bit rate of a CD is 16-bit: 2¹⁶ (65536) values are used to encode the audio digitally | ||
* 8 bit 2⁸ (256) values | * 8 bit 2⁸ (256) values | ||
[[File:Digital_wave.png]] | [[File:Digital_wave.png|500px]] | ||
==audio formats== | ==audio formats== | ||
| Line 137: | Line 134: | ||
* Collins, Nicolas. 2006. Handmade Electronic Music. London: Routledge. | * Collins, Nicolas. 2006. Handmade Electronic Music. London: Routledge. | ||
* “Sound:An Interactive eBook on the Physics of Sound.” 2017. Sound: An Interactive eBook on the Physics of Sound. Accessed January 11. https://soundphysics.ius.edu/. | * “Sound:An Interactive eBook on the Physics of Sound.” 2017. Sound: An Interactive eBook on the Physics of Sound. Accessed January 11. https://soundphysics.ius.edu/. | ||
[[Category:XPUB]] | |||
Latest revision as of 18:49, 8 May 2020
What is sound
We experience sound thought displacement of air molecules from a source to a the receiver.
When a source emits a sound, it makes the air molecules compress and decompress, traveling away from the source.
The rate of this compression-decompression variation is what is called the frequency of a sound. And the amount of air molecules displace give us the amplitude or volume of a sound.
Sound wave properties
- frequency = pitch
- measured in Hertz (Hz) or cycle per second. 1Hz = 1cycle/sec
- amplitude = volume
- measured in decibel (db)
Sound waves on liquid
audible sound
Human audible sound, or the hearing spectrum, is located between 20Hz and 20 000Hz of of the acoustic spectrum
How do we listen?
How does the movement of air molecules gets perceived as sound?
Spacial Perception Sound
How do we detect the position where sound is coming from?
- arrival time difference
- amplitude difference
- filtering, by the outer ear
Janet Cardiff - binaural mics
Hearing as composing
Recording and listening exercise.
- record 1 to 2 minutes of sound
- write down all you here during those minutes, either with or without headphones
4'33
4'33 (1952) is a probably the most famous John Cage composition, where the performance stands in front of the audience without playing a single note, for 4 minutes and 33 seconds.
http://hyperallergic.com/85779/the-original-john-cage-433-in-proportional-notation-19521953/
- hearing as composing
- all sound can become music
Expanded listening
contact mics
- listen to how solid objects respond to vibration
- due to its physical properties each object will respond - resonate - differently to vibration
- The resonant frequencies are the frequencies that are emphasized by the object
David Tudor - Rainforest (1968)
- http://composers-inside-electronics.net/rainforest/rainforest/RAINFOREST.html
- https://www.youtube.com/embed/iT9HP48sHTg
- http://www.getty.edu/research/tools/guides_bibliographies/david_tudor/av/rainforest.html
- Holzer, Derek, and Mads BEch Paulszewski. n.d. “Rainforest 2012.” http://macumbista.net/files/rainforest_overview.pdf
Electromagnetic pickups
Instead of capturing acoustic waves, like acoustic microphones, electromagnetic pickups capture electromagnetic fields.
Christina Kubisch Electrical Walks explore cities electromagnetic fields.
- http://www.christinakubisch.de/en/works/electrical_walks
- http://cabinetmagazine.org/issues/21/cox.php
- https://www.youtube.com/watch?v=5tCphr8pbFk
Digital audio
Analog audio is stored in a continuous analogue to its source.
http://www.synthgear.com/2014/audio-gear/record-grooves-electron-microscope
More grooves: http://sessionville.com/articles/vinyl-through-the-microscope-looking-glass
Digital audio on the other hand is stored discretely (in segments or samples).
sampling rate and bit rate
Two parameters are essential to digital audio:sampling rate and bit rate
sampling rate: how frequently the analogue signal is sampled File:Discrete-signal.png
- The sampling rate of CDs is 44.1KHz: discrete samples of a signal are stored 44100 times each second.
- Digital video cameras tend to store audio at 48KHz.
bit rate: accuracy of sampling - how many values are used to represent the amplitude of a signal
- The bit rate of a CD is 16-bit: 2¹⁶ (65536) values are used to encode the audio digitally
- 8 bit 2⁸ (256) values
audio formats
- uncompressed: aiff, wav, flac
- compressed: mp3, ogg
Editing
With Audacity http://www.audacityteam.org/
“Audacity.” 2017. FLOSS Manuals. Accessed January 11. http://write.flossmanuals.net/audacity. http://archive.flossmanuals.net/audacity/_booki/audacity/audacity.pdf http://archive.flossmanuals.net/audacity/_booki/audacity/audacity.epub
Bibliography
- Collins, Nicolas. 2006. Handmade Electronic Music. London: Routledge.
- “Sound:An Interactive eBook on the Physics of Sound.” 2017. Sound: An Interactive eBook on the Physics of Sound. Accessed January 11. https://soundphysics.ius.edu/.