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