LUFS Analysis FAQ
Everything you need to know about LUFS measurement, loudness standards, and professional audio analysis.
← Back to LUFsterWhat is LUFS and why is it important?
LUFS (Loudness Units Full Scale) is the standard measurement for audio loudness used across broadcast and streaming platforms. Unlike peak measurements, LUFS accounts for human perception of loudness by applying psychoacoustic weighting.
LUFS is crucial for ensuring your audio meets platform standards and sounds consistent across different playback systems. It prevents the "loudness war" by providing objective loudness measurement that correlates with how we actually hear audio.
What is EBU R128 and why does it matter?
EBU R128 is the European Broadcasting Union standard for loudness measurement and normalization. It defines how LUFS should be measured and provides guidelines for broadcast loudness levels. This standard ensures consistent audio levels across different programs and platforms, making it essential for professional audio work.
What are the common loudness targets for different platforms?
Streaming Platforms:
- Spotify: -14 LUFS integrated
- Apple Music: -16 LUFS integrated
- YouTube: -14 LUFS integrated
- Amazon Music: -14 LUFS integrated
Broadcast:
- TV/Radio (EBU R128): -23 LUFS integrated
Other Applications:
- Club/DJ: -9 to -13 LUFS (louder for club systems)
- Podcast: -16 to -20 LUFS
What's the difference between integrated, short-term, and momentary loudness?
- Integrated Loudness: Average loudness over the entire duration of the audio. This is the main measurement used for streaming platform compliance.
- Short-term Loudness: Loudness measured over a 3-second sliding window. Useful for identifying the loudest sections of your track.
- Momentary Loudness: Loudness measured over a 400ms sliding window. Shows very short-term loudness fluctuations.
What is True Peak and why should I care about it?
True Peak measures the maximum sample value including inter-sample peaks that can occur during digital-to-analog conversion. It should stay below 0 dBFS (preferably -1 to -2 dBFS) to prevent clipping and distortion in playback systems. Even if your digital peaks don't clip, true peak can exceed 0 dBFS and cause problems.
What is Loudness Range (LRA) and what does it tell me?
Loudness Range (LRA) measures the dynamic variation in your audio, expressed in LU (Loudness Units). Higher values indicate more dynamic content, while lower values suggest more compressed audio. Typical values range from 5-20 LU, with heavily compressed music around 3-7 LU and more dynamic content reaching 15+ LU.
How accurate is browser-based LUFS analysis?
Browser-based analysis using Web Audio API can be very accurate when properly implemented. Our tool uses industry-standard algorithms for LUFS calculation that match professional hardware and software meters. The main limitation is the audio file quality you upload - lossless formats like WAV will give the most accurate results.
Why don't my files leave my computer?
All audio processing happens locally in your browser using the Web Audio API and FFmpeg WebAssembly. Your files are never uploaded to our servers, ensuring complete privacy and faster processing. This also means the tool works offline once loaded.
What audio formats are supported?
LUFster supports WAV, AIFF, MP3, M4A, and FLAC files. For the most accurate analysis, use uncompressed formats like WAV or AIFF. Compressed formats like MP3 can still provide useful measurements but may have slight variations due to compression artifacts.
How does this compare to professional loudness meters?
LUFster implements the same EBU R128 algorithms used in professional hardware and software meters. While it may not have every advanced feature of expensive dedicated tools, it provides accurate LUFS measurement suitable for most professional applications including streaming platform compliance and broadcast preparation.
Can I use this for mastering decisions?
Yes, LUFster can help inform mastering decisions by showing you how your audio measures against target loudness levels. However, remember that loudness is just one factor in mastering - you should also consider musical dynamics, tonal balance, and how the audio sounds on different playback systems.
What if my audio is too loud or too quiet?
If your integrated LUFS is:
- Too loud: Your audio may be heavily limited/compressed. Consider reducing limiting or using less aggressive compression.
- Too quiet: You may need more gain or limiting to reach target levels, but be careful not to over-compress.
Remember that streaming platforms will adjust your audio to their target level anyway, so it's better to maintain dynamics than chase maximum loudness.
Professional Resources
Standards & Documentation
- • EBU R128 Loudness Recommendation
- • ITU-R BS.1770 Loudness Algorithms
- • AES Streaming Loudness Guidelines
- • Platform-specific loudness requirements
Professional Applications
- • Streaming platform compliance
- • Broadcast content preparation
- • Mastering workflow integration
- • Quality control and monitoring