CMP Mixing and Mastering Principles 3 — Questions and Answers
Question 1: What does 'headroom' mean in the context of mixing?
- The physical space above studio monitor tweeters
- The amount of dynamic range available between the loudest peak and 0 dBFS (clipping) (Correct answer)
- The reverb decay time of the recording room
- The gain applied to the input of the audio interface
Correct answer: The amount of dynamic range available between the loudest peak and 0 dBFS (clipping)
Headroom is the buffer between the loudest signal peak and the clipping point (0 dBFS), giving the mastering engineer dynamic range to work with.
Question 2: Which of the following best describes a 'stereo width' issue in a master where the mix collapses to mono?
- Excessive reverb on the lead vocal
- Phase cancellation occurring when the Mid signal is too dominant relative to the Side signal (Correct answer)
- Too much high-frequency content on the master bus EQ
- Overuse of parallel compression on the stereo bus
Correct answer: Phase cancellation occurring when the Mid signal is too dominant relative to the Side signal
When the Side signal is weak or out-of-phase elements cancel in mono, the stereo mix collapses; mono-compatibility checks and M/S processing can diagnose and fix this.
Question 3: In mastering, what is the typical use of a multiband compressor versus a broadband compressor?
- Multiband compressors process each frequency range independently, while broadband compressors affect the full spectrum with a single set of controls (Correct answer)
- Broadband compressors are used for mastering and multiband only for mixing
- Multiband compressors are only used for podcast mastering
- Broadband compressors are preferred for electronic music; multiband for acoustic music
Correct answer: Multiband compressors process each frequency range independently, while broadband compressors affect the full spectrum with a single set of controls
A multiband compressor splits the signal into frequency bands and compresses each independently, allowing surgical dynamic control without affecting unrelated frequencies.
Question 4: What is the function of a brickwall limiter at the final stage of mastering?
- To add harmonic saturation for warmth
- To prevent the output signal from exceeding a set ceiling, typically -0.1 to -1 dBTP (Correct answer)
- To compress the low end of the mix separately from the mids
- To apply dithering noise to the output file
Correct answer: To prevent the output signal from exceeding a set ceiling, typically -0.1 to -1 dBTP
A brickwall limiter enforces a hard ceiling on the output level, preventing digital clipping while allowing the engineer to raise perceived loudness.
Question 5: What is 'dithering' and when should it be applied?
- A form of stereo enhancement applied during mix-down
- Low-level noise added to minimize quantization distortion when reducing bit depth, applied as the last process in the chain (Correct answer)
- A technique to increase the sample rate of a mix for streaming
- A modulation effect added to pad sounds for movement
Correct answer: Low-level noise added to minimize quantization distortion when reducing bit depth, applied as the last process in the chain
Dithering adds shaped low-level noise to mask quantization distortion when reducing bit depth (e.g., 24-bit to 16-bit for CD), and must always be the very last process.
Question 6: What does a correlation meter (phase meter) reading of -1 indicate in a stereo mix?
- The mix is perfectly mono compatible
- The left and right channels are completely out of phase, causing total cancellation in mono (Correct answer)
- The mix has ideal stereo width for club playback
- The mid frequency range is over-compressed
Correct answer: The left and right channels are completely out of phase, causing total cancellation in mono
A correlation meter reading of -1 means the two channels are perfectly out of phase and will cancel each other completely when summed to mono.
Question 7: Which technique is used to make a snare drum cut through a dense mix without increasing its overall level?
- Adding low-frequency content around 80 Hz
- Boosting presence frequencies (typically 2–5 kHz) and compressing with a fast attack (Correct answer)
- Applying a long reverb tail to create space around the snare
- High-pass filtering the snare above 1 kHz
Correct answer: Boosting presence frequencies (typically 2–5 kHz) and compressing with a fast attack
Boosting the attack transient range (2–5 kHz) enhances the snare's crack and presence, helping it cut through without simply pushing the fader up.
CMP Mixing and Mastering Principles 3
What does 'headroom' mean in the context of mixing?