All our customers share one expectation: a smooth, consistent musical experience without sudden jumps or dips in volume. Ideally, every track should feel equally loud, no matter where it comes from.
The technical process that ensures this is called Loudness Normalisation. While it may sound straightforward, it’s actually a challenging engineering problem.
To solve it, SPECTRE implements the ITU-R BS.1770 (formerly known as EBU R128) algorithm. — the current industry gold standard. It’s the same method used by Apple, Spotify, Tidal, Netflix, Sony, and countless broadcasters worldwide.
However, this algorithm isn’t a silver bullet. In certain cases, normalized tracks may still sound slightly too quiet or too loud. These corner cases usually involve the following factors:
Factors That Can Affect Loudness Perception
Speaker quality
“Full-range” speakers reproduce the full spectrum of human hearing (20Hz–20kHz). Most high-fidelity systems qualify.
Non-music-focused systems (e.g., PA or emergency speakers) often fail to reproduce deep bass or high treble. The missing frequencies will lead to an overall diminished perceived loudness.
Bass-heavy tracks, and treble-heavy tracks
Some tracks emphasize low (bass) or high (treble) frequencies.
On speakers that aren’t full-range, these tracks can feel quieter than balanced ones.
Our Art Directors avoid such tracks when possible, though creative constraints sometimes require them.
Highly dynamic tracks
These tracks have big differences between quiet and loud sections (common in classical and jazz, but found across genres).
The ITU-R BS.1770 algorithm does not compress dynamics (it does not reduce this loudness gap within a track) — preserving artistic intent but leaving wide loudness gaps.
We avoid highly dynamic tracks when feasible, though some briefs require them.
If your sound system supports it, using an audio compressor can help reduce the dynamic range, with some trade-offs in quality.
Other factors
Other less likely possible factors can include :
Poor room acoustics: bad room acoustics can lead to some frequency ranges feeling louder/quieter than others. This can lead to perceived loudness fluctuations between tracks.
Equalization issues: Incorrect EQ settings can also cause perceived loudness differences between tracks.