ITEC2110:AudacityAndSoundResources

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Contents

Resources


James Robinson Audio Project

‘’’Use 28.8Kbps for dialup downloading speed and 1.5Mbps for DSL downloading speed.’’’

Uncompressed vs. Compressed

Format

File size

Download time (Dialup)

Download time(DSL)

Link to Download

Using Audacity I produced a WAV format file which is:

4.43 MB

00 Hours 32 Min 26 Sec

2 Min 13 Sec

Click here to download this version

Using Audacity I produced a MP3 format file which is:

1.41 MB

00 Hour 16 Min 21 Sec

1 Min 34 Sec

Click here to download the MP3 version


Quantization and Sampling Rates

CD quality audios are usually sampled at 44,100 samples per second with a 2 byte quantization level.

Format

File size

Dialup download time

ADSL download time

Download

With Audacity, here is a WAV format file which has a sample rate of 44100 samples per second and a quantization level of 32 bits:

10.6 MB

0 Hours 52 Min 33 Sec

2 Min 46 Sec

click here to download this version

With Audacity, here is a WAV format file which has a sample rate of 44100 samples per second and a quantization level of 16 bits:

169 MB

1 Hours 21 Min 12 Sec

4 Min 18 Sec

Click here to download this version

With Audacity, here is a WAV format file which has a sample rate of 8000 samples per second and a quantization level of 16 bits:

1.41 MB

00 Hours 13 Min 45 Sec

01 Min 03 Sec

Click here to download this version


Reflection Questions

  • What’s the difference between WAV format and MP3 format and how different formats affect downloading time ? (Hint: file size; compression)
Answer: WAV files are much larger that MP3 files, the WAV format is uncompressed format; while MP3s use compression methods to decrease file size. Being that a WAV file is much larger, the download time is expected to be longer, as for the MP3; the download is shortened because it is an compressed file.
  • Do you know any other audio format? Please list at least two.
Answer: Different audio formats include AAC (Advanced Audio Decoding), AIF(F) (Audio Interchange File Format), and WMV (Windows Media Video)
  • How sampling and quantization affect audio quality?
Answer: Sampling reduces the maximum reconstructed frequency, where quantization has the effect of making the reconstructed signal sound digitized.


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Special thanks to Stephen Kent who re-organized the submission template.

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