skills: microphone position and adjustment concepts: clipping, dynamic range, sample frequency and...
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Skills: microphone position and adjustmentConcepts: clipping, dynamic range, sample frequency and size, amount of data and information captured, fidelity
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Audio recording
Where does this topic fit?
• Internet concepts– Applications– Technology– Implications
• Internet skills– Application development– Content creation– User skills
Recording controls
Shift to append
Waveform display
Microscopic zoom
Which of these recordings is higher fidelity?
Explain your answer using the word “information.”
Which recording requires more memory?
Explain your answer using the word “bit.”
Higher fidelity → larger data files
CD audio
• Sampling rate: 44.1 kHz
• Sample size: 16-bit
• Number of tracks: 2 (stereo)
Microphone position
Experiment with microphone settings and placement
The signal isclipped
The signal does not use the full dynamic range
Like Goldilocks said, just right
Adjusting recording volume in Windows
Control panel > Sound > Record > Properties > Levels
mute
You need a microphone
Your first recording – Audacity help
Tutorial - your first recording
Summary
Self-study questions
1. Record something with the microphone volume set too high so clipping occurs. What does it sound like?
2. Record something in which you speak very quietly, then amplify it. How is the sound quality?
3. Record something at 8,000 Hz – how does the sound quality compare to a 44,100 Hz recording?
4. If you make a ten second recording at 8,000 Hz with 16 bit samples, how large will the file be?
5. If you make a 60 minute recording at 44,100 Hz with 32-bit samples, how large will the file be?
6. We said high fidelity recordings produce large files. What do we do to reduce the size of a file before we distribute it?
ResourcesAudacity audio recorder and editor:http://audacity.sourceforge.net/download/Audacity audio recorder and editor, portable version:http://portableapps.com/apps/music_video/audacity_portableAudacity "how to" videos:http://www.wonderhowto.com/search/audacityLAME, an mp3 encoder for Audacity:http://lame.buanzo.com.arFFMpeg, a WMA encoder for Audacity:http://manual.audacityteam.org/index.php?title=FAQ:Installation_and_Plug-Ins#installffmpegAudacity keyboard shortcuts:http://audacity.sourceforge.net/manual-1.2/keyboard_shortcuts.htmlAudacity: how-to presentation:http://pa.gigavox.com/shows/detail1595.htmlAudacity Wiki:http://audacityteam.org/wikiAudacity threaded discussion forum:http://audacityteam.org/forumAudacity tutorial (on Mac, but good for Windows too):http://homepage.mac.com/s_sloan/apsc_2007/audacity_jmc.pdfAudacity del.icio.us:http://del.icio.us/search/?fr=del_icio_us&p=audacity&type=allNeil Young on the need for higher quality music audio:http://www.wired.com/gadgetlab/2012/02/why-neil-young-hates-mp3-and-what-you-can-do-about-it/
Download lame.dll, an mp3 encoder for Audacity:http://lame1.buanzo.com.ar/Lame_v3.99.3_for_Windows.exe
LAME download manual page:http://manual.audacityteam.org/man/FAQ:Installation_and_Plug-Ins#How_do_I_download_and_install_the_LAME_MP3_encoder.3F
Home of the LAME project:http://lame.sourceforge.net/index.php
Why Mike Cheng started the LAME project:http://lame.sourceforge.net/rationale.php
FFMpeg, a WMA encoder for Audacity (to export .wav files):http://manual.audacityteam.org/index.php?title=FAQ:Installation_and_Plug-Ins#installffmpeg