Audiobook Production Audio Editing and Post-Production 2 — Questions and Answers
Question 1: What does 'normalization' do to an audiobook audio file?
- Applies compression to the dynamic range
- Adjusts the overall level so the highest peak reaches a target value (Correct answer)
- Removes background noise automatically
- Converts stereo to mono format
Correct answer: Adjusts the overall level so the highest peak reaches a target value
Normalization raises or lowers the entire file's gain so that the loudest peak hits a specified target level, commonly -3 dBFS for ACX delivery.
Question 2: What is a 'compressor' used for in audiobook post-production?
- To reduce the file size for distribution
- To reduce the dynamic range by lowering loud peaks (Correct answer)
- To increase the bit depth of the recording
- To filter out background noise
Correct answer: To reduce the dynamic range by lowering loud peaks
A compressor automatically reduces the gain of audio that exceeds a set threshold, evening out the loud and quiet passages for a more consistent listening experience.
Question 3: What is the ACX maximum noise floor requirement for audiobook audio files?
- -30 dB RMS
- -40 dB RMS
- -60 dB RMS (Correct answer)
- -20 dB RMS
Correct answer: -60 dB RMS
ACX requires the noise floor—the background noise present in silence—to be at or below -60 dB RMS to ensure a quiet, professional-sounding recording.
Question 4: What is the purpose of a 'limiter' as the final stage in an audiobook mastering chain?
- To add warmth to the vocal recording
- To prevent peaks from exceeding a set ceiling and causing clipping (Correct answer)
- To apply stereo widening to the audio
- To increase the sample rate for delivery
Correct answer: To prevent peaks from exceeding a set ceiling and causing clipping
A limiter acts as a hard ceiling, preventing any audio transient from exceeding a maximum level such as -3 dBFS, ensuring clean delivery without digital clipping.
Question 5: What does the term 'punch and roll' refer to in audiobook recording?
- A technique for creating dramatic pauses
- Re-recording from just before a mistake by punching in mid-sentence (Correct answer)
- A method of layering multiple vocal takes
- A post-processing technique to add reverb
Correct answer: Re-recording from just before a mistake by punching in mid-sentence
Punch and roll allows the narrator to play back the recording, then seamlessly 'punch in' to re-record from a point just before an error, maintaining flow.
Question 6: Which export file format does ACX require for audiobook submission?
- WAV
- FLAC
- MP3 (Correct answer)
- OGG
Correct answer: MP3
ACX requires audiobook files to be submitted as MP3s at 192 kbps or higher, encoded as constant bit rate (CBR) mono files.
Audiobook Production Audio Editing and Post-Production 2
What does 'normalization' do to an audiobook audio file?