CEA Mastering and Loudness Standards

Question 1

What is the target integrated loudness standard specified by the EBU R 128 specification for broadcast content?

Accepted Answer

-23 LUFS

Answer

EBU R 128 specifies a target integrated loudness of -23 LUFS (equivalent to -23 LKFS) for European broadcast delivery. This standardized loudness level prevents the 'loudness war' on broadcast by normalizing all content to a consistent perceived level.

Question 2

What does 'true peak' measurement differ from standard 'sample peak' measurement in digital mastering?

Accepted Answer

True peak detects intersample peaks that occur during digital-to-analog conversion and can exceed 0 dBFS, while sample peak only measures the highest discrete sample value

Answer

Intersample peaks occur when the waveform reconstructed during D/A conversion exceeds the original sample values between samples, potentially exceeding 0 dBFS and causing clipping in decoders. True peak metering detects these reconstructed peaks, allowing mastering engineers to apply appropriate limiting.

Question 3

What is 'dithering' and when should it be applied in mastering?

Accepted Answer

The addition of a shaped low-level noise signal when reducing bit depth (e.g., 24-bit to 16-bit) to minimize quantization distortion artifacts

Answer

Dithering adds a precisely shaped noise signal (noise shaping) before bit depth reduction to minimize audible quantization distortion. It should be applied only once at the final stage of bit depth reduction (e.g., when converting a 24-bit master to 16-bit for CD delivery). Double-dithering degrades audio quality.

Question 4

What is 'dynamic range' in the context of mastering and loudness?

Accepted Answer

The difference between the quietest and loudest levels in a program, often expressed using PLR (Program Loudness Range) or DR rating

Answer

Dynamic range in mastering refers to the variation in loudness within a program — the difference between the softest and loudest passages. It is quantified by PLR (Peak-to-Loudness Ratio = max true peak − integrated loudness) or the Crest Factor. The DR (Dynamic Range) database uses RMS-based measurements.

Question 5

What loudness target does Spotify use for its normalized playback level?

Accepted Answer

-14 LUFS

Answer

Spotify normalizes playback to approximately -14 LUFS integrated loudness. Masters significantly louder than -14 LUFS are turned down on Spotify; masters quieter than -14 LUFS are turned up. Mastering to -14 LUFS ensures no loudness penalty and preserves dynamic range.

(CEA) Certified Audio Engineer Practice Test

(CEA) Certified Audio Engineer Practice Test

CEA Mastering and Loudness Standards