Exporting audio at different quality levels in Audacity
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. You want to save your Audacity recording as a compressed MP3. Which menu path do you use?
2. You export the same recording once as WAV and once as MP3. Which file will usually be smaller?
3. Which statement about a WAV export is correct?
4. You export an MP3 at 64 kbps and another at 320 kbps. Which is likely to sound closer to the original?
5. Your teacher wants the smallest file that is still OK for a podcast. What should you do in the export settings?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1File > Export > Export as WAV | ABit Rate Mode: Constant, Quality: 64 kbps | |
| 2File > Export > Export as MP3 | BA high bitrate such as 320 kbps keeps more data, so it gives a larger file with better quality. For the smallest file you would choose a low bitrate such as 64 kbps. | |
| 3To hear how much detail is lost, you choose a lower quality or bitrate setting when exporting an MP3 and then compare the result with the original. | CSaves the recording as a compressed MP3 file with some detail removed, so the file is much smaller than the WAV. | |
| 4To check the exported files, compare the file size of each version in the folder and listen to each one. | DSaves the recording as an uncompressed WAV file that keeps every digital sample, so it has the biggest file size and full quality. | |
| 5Export as MP3 at 320 kbps to get the smallest file | EWAV keeps every sample and is not compressed in this way, so it is usually larger than the MP3. MP3 is the format that removes detail to save space. | |
| 6Exporting as WAV removes detail so the file is smaller than the MP3 | Fsong.wav = 50 MB, song.mp3 = 5 MB |
C
Definitions
File > Export
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
File > ______ > Export as MP3
2.
File > Export > Export as ___
# lossless, biggest file size
3.
Export as MP3
Quality: 128 ____
4.
View > Zoom > Zoom __
# see the individual samples
5.
size(MP3) _ size(WAV)
# lossy file is smaller
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
Record a 10 second clip
B
File > Export as MP3
C
Choose bitrate 128 Hz
Question 2
A
Open the recorded track
B
File > Import as WAV
C
Name the file clip.wav
Question 3
A
Export clip.wav (lossless)
B
Export clip.mp3 at 64 kbps
C
Check both file sizes
D
MP3 file is larger than WAV
Question 4
A
Zoom in on the waveform
B
Each dot is one sample
C
Samples are stored as letters
Question 5
A
Export MP3 at 320 and 64 kbps
B
The 320 kbps file is smaller
C
It keeps more sound detail
Answer Key
Exporting audio at different quality levels in Audacity
Section A: Quick Questions
Q1
A — File > Export > Export as MP3
Q2
B — The MP3 file
Q3
A — It keeps all the digital samples, so it is not compressed
Q4
B — 320 kbps
Q5
A — Choose a lower bitrate and listen to check the quality
Section B: Match the Pairs
Q1
File > Export > Export as WAV → Saves the recording as an uncompressed WAV file that keeps every digital sample, so it has the biggest file size and full quality.
Q2
File > Export > Export as MP3 → Saves the recording as a compressed MP3 file with some detail removed, so the file is much smaller than the WAV.
Q3
To hear how much detail is lost, you choose a lower quality or bitrate setting when exporting an MP3 and then compare the result with the original. → Bit Rate Mode: Constant, Quality: 64 kbps
Q4
To check the exported files, compare the file size of each version in the folder and listen to each one. → song.wav = 50 MB, song.mp3 = 5 MB
Q5
Export as MP3 at 320 kbps to get the smallest file → A high bitrate such as 320 kbps keeps more data, so it gives a larger file with better quality. For the smallest file you would choose a low bitrate such as 64 kbps.
Q6
Exporting as WAV removes detail so the file is smaller than the MP3 → WAV keeps every sample and is not compressed in this way, so it is usually larger than the MP3. MP3 is the format that removes detail to save space.
Section C: Definitions
Q1
File > Export — Audacity menu path that saves a recording as WAV or MP3 at a chosen quality, so you can compare file size and sound quality of the same audio.Section D: Fill in the Blanks
Q1
File > Export > Export as MP3Q2
File > Export > Export as WAV
# lossless, biggest file sizeQ3
Export as MP3
Quality: 128 kbpsQ4
View > Zoom > Zoom In
# see the individual samplesQ5
size(MP3) < size(WAV)
# lossy file is smallerSection E: Spot the Error
Q1
C — MP3 bitrate is measured in kilobits per second (kbps), not Hz. Hz measures sample rate. It should be 'Choose bitrate 128 kbps'.
Q2
B — Import brings a file into Audacity. To save a recording as a WAV you use File > Export. It should be 'File > Export as WAV'.
Q3
D — WAV keeps all the sample data, so it is bigger. MP3 is compressed and smaller. It should be 'WAV file is larger than MP3'.
Q4
C — Each sample is a number that records the height of the sound wave at one moment. They are not stored as letters. It should be 'Samples are stored as numbers'.
Q5
B — A higher bitrate stores more data per second, so the file is larger. The 320 kbps file is larger than the 64 kbps file.