Audio
Audio Recording
Our next unit in soft tech will be about how to effectively record sound using our phones. We will have a few projects to get the hang of it, followed by a marked exercise.
Whether you are producing an AUDIO PODCAST, a RADIO PROMOTION or enhancing an ANIMATION or VIDEO PRODUCTION, learning to use audio effectively is critical to creating a successful media project.
There are THREE categories of audio we'll learn to add to our projects: Voice Recordings, Sound Effects and Creative Commons Music
Recording Audio is Technical
Analog vs Digital Recording
Audio Wave Form Characteristics
Frequency ie "Pitch"
Amplitude ie "Volume"
Wave Shape & Harmonics ie. a note played on a flute sounds different than the same note on a violin
Digital Audio Characteristics
Sample Rate ie. 44.1 KHZ
Bit Depth ie. 16bit
Digital Storage Options
File Format ie. MP3 vs WAV
Compression ie 256kbps vs 320kbps
Sampling Rate and Bit Depth
SAMPLE RATES
44,100 Hz (44.1KHz) is CD Quality
48,000 Hz (48KHz) Professional Audio Editing
96,000 Hz (96KHz) DVD Audio Quality surr sound
BIT DEPTH
8 bit
16 bit
Sample Rate x Bit Depth = File size often measured in Bits per Second or Bitrate
CREATE AUDIO with AUDACITY
Audacity is a free, powerful piece of software that runs on Windows computers. We'll be using it to learn audio editing
Chromebook users can try Twisted Wave for simple editing, or SoundTrap for multitrack and music creation similar to garageband
Open the latest version of Audacity on your computer. If it's less than version 2.3, you should download and install the latest version of Audacity (download the INSTALLER) for this exercise so the menu commands are accurate - (Click the INSTALLER for the latest version to download it - let it install to "C:/Windows/Audacity")
If you want to hear the sound you're about to make, use Earbuds or headsets borrowed from the front of the class
Generate a 1 second tone
Go to the menu GENERATE and select Tone
Change the AMPLITUDE to 0.6 (so it's not too loud)
Change the Duration to 01.000 seconds (so it's not too long)
Press OK
Check out your new SINE WAVE
Hold the CTRL key on your keyboard and roll the mouse wheel to ZOOM IN on the wave
You'll see that the wave is actually a smooth, evenly spaced shape called a sine wave
Zoom in even further, and you'll see that the wave is actually made of specific dots representing values of AMPLITUDE at specific slices of TIME. This is the basis of representing sound digitally.
Just as IMAGES can be represented using PIXELS of colour in a specific grid pattern, SOUND can be represented using values of AMPLITUDE at specific SAMPLE RATES
Try generating other wave shapes besides SINE to see what they look and sound like