Basics of Digital Audio

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Pioneers in Sound recording
• Tony Schwartz
https://www.youtube.com/watch?v=6gaq5-t14FE
• Alan Lomax
http://research.culturalequity.org/rc-b2/get-audioix.do?ix=recording&id=4735&idType=performerI
d&sortBy=abc
Basics of Digital Audio
-Frequency = speed, measured in Hertz (Hz)
-Volume = level, measured in decibels (db)
-Sample rate is the number of samples recorded per
second-measured in Hz or kHz. A CD has a rate of 44,100
Hz.
-Sample size or format is the number of digits in digital
representation of sample. Measured in bits, a CD is 16
bits. The higher the sample size the more dynamic rangelouder louds and softer softs. Measured in bits-16 bits
being standard for CD quality.
File Formats
• Most common types of file formats:
AIFF, WAV, MP3, Ogg Vorbis, AAC & WMA
-Uncompressed and high quality-AIFF, WAV
-Compressed but small file size - MP3, Ogg
Vorbis
-MPEG4 or AAC (Apple) and WMA (Windows)
are proprietary and not supported by
Audacity.
Basics of Digital Audio
http://www.hammersound.net/audiobasics/audiobasics.html
-Explains theory behind digital audio
http://ohda.matrix.msu.edu/2012/06/digital-audio-recording/
Digital Audio Basics for Oral Historians
http://www.nch.com.au/acm/formats.html
-Useful resource that explains different formats.
Uses for Audio in Digital Humanities
Oral Histories
Podcasts
Documentaries
Exhibits
Slide Presentations
Installations
Mashups
Performance
Education
Uses for Audio in Digital Humanities Projects
• Oral Histories
-voice recordings where a speaker tells her eye
witness account, experience(s), or opinion(s).
-audio emphasis is on the human voice.
Uses for Audio in Digital Humanities Projects
• Oral Histories
http://www.aaa.si.edu/collections/interviews
Archives of American Art
-Includes excerpt on website, must visit archive for
whole file.
-Includes link to archival collection and finding aid
to give context.
Uses for Audio in Digital Humanities Projects
• Oral Histories
http://cds.library.brown.edu/projects/1968/narr
ators/B.KERR.html
The Whole World was Watching
-Includes transcript
-Cues with content headings
Uses for Audio in Digital Humanities Projects
• Oral Histories
http://www.britannica.com/dday/browse?browse
Id=237157
Veteran’s Oral Histories
-Link to audio
-Description with credit
Uses for Audio in Digital Humanities Projects
• Oral Histories
-Library of Congress how to plan an Oral History
Project
http://www.loc.gov/folklife/familyfolklife/oralhistor
y.html
-Google Transcribe - audio player for transcription.
-Testimony Software
http://storytelling.concordia.ca/oralhistorianstoolbox/
pop_up_pages/testimony_software_pop_up.html
Uses for Audio in Digital Humanities Projects
• Podcasts
-Generally an audio episode, self-contained,
sometimes augmented by text or visuals, that
can be either streamed or downloaded.
-Uses an rss feed (really simple syndication),
to update new content. This feed is an XML
file created when you make a new podcast.
Uses for Audio in Digital Humanities Projects
• Podcast Resources
http://www.cnet.com/how-to/how-to-podcast-step-bystep/
http://www.podcasting-tools.com/
Where to host your podcast:
http://soundcloud.com/explore/storytelling
https://www.apple.com/itunes/podcasts/
https://archive.org/details/audio_podcast
Uses for Audio in Digital Humanities Projects
Examples of Podcasts
http://mariehicks.net/blog/?p=486#comments
A class project where groups interviewed a professor
and created podcasts posted to YouTube.
http://www.axonsandaxioms.com
A podcast dedicated to philosophy created by two
assistant professors, one from Carnegie Mellon and the
other from the University of Pittsburgh.
Uses for Audio in Digital Humanities Projects
• Other uses: Documentaries, Exhibits, Slide
Presentations, installations, mashups,
performance and in education
• http://chronicle.com/blogs/profhacker/integr
ating-digital-audio-composition-intohumanities-courses/24266
Other things to consider
• Copyright Issues
-Releases
-The Veteran’s History Project
http://www.loc.gov/vets/pdf/vetsreleasefieldkit-2007.pdf
Others things to consider
• Copyright Issues
-Using Creative Commons, essay at:
http://ohda.matrix.msu.edu/2012/06/acreative-commons-solution/
-Non-commercial-share alike-where participants
can retain copyright, but material can be shared
and used for non commercial purposes.
Rights Issues
• Resources
FreeSound
Internet Archive
Freemusicarchive
-For soundscapes or mashups
http://creativecommons.org/audio/
Metadata for access
• Transcript is important since textual material
describes content.
• Simple metadata about project can be used
for access.
• Various form of metadata- Dublin Core,
MODS, TEI
• Tagging
Metadata for Access
• BWFmetaedit-metadata for audio
http://sourceforge.net/projects/bwfmetaedit/
• Praat & Akustyk-open source speech analysis
http://www.fon.hum.uva.nl/praat/
http://bartus.org/akustyk/
Recording Basics
• Microphone-Computer-Audacity
• Skype for out-of-town subjects
• Low Cost recording setups
International Association of Internet Broadcasters
http://www.ibroadcastnetwork.org/blog/bestdynamic-microphones-under-100-dollars
Recording Basics
• Best settings for recording
-Microphone!
-For multiple speakers, more than one
microphone should be plugged into a mixer
that then gets plugged into computer.
-Recording room tone to mask any silent spots
or use as a “noise print” to take out hum or
background noise.
Using Audacity
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Settings
Importing Files
Cutting and placing clips
Adding tracks as bins
Setting the volume
Tools
Saving project/Exporting File
Using Audacity
• Cleaning up pops, background noise, and “ums”
and coughs.
• Normalizing Audio
• Loudest part of your recording should approach
0db on a VU meter, anything above will distort.
• Creating files for different applications.
• The importance of keeping high resolution
master files.
Washington Post article on adding effects to
Photos using Audacity
http://www.washingtonpost.com/blogs/innovati
ons/wp/2014/07/23/what-paris-looks-like-withan-echo/
Tutorial
http://questionsomething.wordpress.com/2012
/07/26/databending-using-audacity-effects/
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