A Mastering Glossary for Beginners
Published · by Loopin
Mastering terminology can feel like a wall of jargon when you're starting out. Here's what the core terms actually mean for your track, not just a technical dictionary definition.
LUFS and true peak: the two loudness numbers that matter
LUFS (integrated) measures perceived loudness across your whole track — the number streaming platforms use to normalise playback, target roughly −14. True peak (dBTP) measures the absolute highest point your signal reaches, including hidden peaks between digital samples — keep this at −1 dBTP or lower to avoid clipping during format conversion.
These are the two numbers worth actually understanding and checking on every master, even if you don't learn anything else in this glossary.
Limiter and compressor: controlling dynamics
A compressor reduces the difference between loud and quiet parts, evening things out. A limiter is a more extreme, hard-ceiling version specifically designed to prevent anything from crossing a set level — it's what makes a track louder overall without clipping.
Both are dynamics tools; the difference is intensity and purpose. Compression shapes and evens; limiting sets a hard, protective ceiling.
EQ, mud, and harshness: shaping tone
EQ (equalization) adjusts the balance between different frequencies — boosting or cutting specific ranges. "Mud" refers to congestion typically in the 250–500 Hz range that makes a track sound thick and undefined. "Harshness" refers to an uncomfortable, fatiguing quality usually in the 2–7 kHz range.
Most corrective mastering EQ work is aimed specifically at reducing one or both of these two common problems.
Mono compatibility and stereo width
Stereo width refers to how spread out a mix feels between left and right speakers. Mono compatibility means checking that a mix still sounds good when those two channels get combined into one — important since many real-world playback systems are effectively mono.
Keeping bass centered (not spread wide in stereo) is the most common practical step for protecting mono compatibility.
Normalisation and headroom
Normalisation is what streaming platforms do automatically to adjust every track to a consistent perceived loudness on playback. Headroom is the space between your actual signal level and the maximum possible level (0 dBFS) — leaving headroom protects against clipping at every stage of processing and distribution.
Understanding these two concepts together explains why chasing extreme loudness in your own master doesn't actually make it play back louder, and why leaving safety margin matters throughout the process.
Frequently asked questions
What's the difference between LUFS and true peak?
LUFS measures perceived loudness across the whole track, which streaming platforms use for normalisation. True peak measures the absolute highest point the signal reaches, including hidden inter-sample peaks, which matters for avoiding clipping during format conversion.
What does 'mud' mean in mastering?
Congestion typically in the 250-500 Hz range that makes a track sound thick and undefined rather than clear and punchy. It's one of the two most common corrective EQ targets in mastering, along with harshness.
Why does normalisation mean mastering louder doesn't help?
Streaming platforms automatically adjust every track to a consistent perceived loudness on playback. Pushing your master louder than the platform's target just gets turned back down, so it doesn't actually play back louder -- it only costs dynamic range.