Loudness Explained: LUFS vs. RMS vs. dBFS and More
Volume level is one of the most noticeable differences between a DIY track and one produced by a Grammy-winning engineer. It can be frustrating to put your Spotify release in a playlist beside your favorite artists' songs and notice that theirs are significantly louder than yours. The volume drop-off is a fast track toward listeners skipping to the next song.
Solving streaming volume issues is more complicated than simply boosting the volume in your DAW before bouncing. Producers need to understand the inner workings of loudness and apply the knowledge to their mixing and mastering processes. Today, we'll dive into loudness to see how you can ensure your next release stacks up with the pros.
Understanding Loudness and Decibel Level
There are two primary ways of analyzing a song's volume. One way is to assess its decibel level. Another is to measure loudness.
A song's decibel level is a ratio that describes its intensity. A higher decibel level generally equates to a louder song, but the science isn't that exact. Other factors outweigh the decibel level in determining perceived volume — the most critical being loudness.
Loudness considers how the listener perceives your song — it's more of a feeling than a quantifiable value. Achieving competitive loudness comes through strategic mixing and mastering to create space and dynamics within your track. Again, loudness is primarily a feeling, but a few metrics can help producers get it right.
Essential Metrics in Music Production — LUFS, dBFS and RMS
The three most important metrics for producers to know when mixing and mastering for optimal loudness are LUFS, dBFS and RMS.
What Is LUFS?
LUFS, or loudness units relative to full scale, is potentially one of the most important metrics for modern music producers to understand and apply. LUFS can operate as an integrated loudness measurement that describes the average perceived loudness of an entire track or as a short-term value that assesses the last three seconds of playback. Many of the media outlets that will feature your music are moving toward LUFS as their primary metric for defining the levels that perform best on their platforms.
Monitoring LUFS in DAWs like Logic Pro X and Avid Pro Tools or PreSonus Studio One is easy using preloaded loudness meters for both momentary and integrated loudness. There are also numerous free LUFS meter plug-ins you can download online.
What Are dBFS?
The unit dBFS, or decibels relative to full scale, is the other half of the dichotomy between loudness and decibel level. This measurement assesses and quantifies a soundwave's amplitude, with 0 dBFS being the maximum level. Clipping will occur if a song goes beyond 0 dBFS, causing distortion you may not want from a producer's standpoint. Anything below -18 dBFS is practically inaudible.
dBFS is one of the easiest metrics to spot when working in your DAW. You'll find your song's dBFS in the standard volume meter on your track's master region on each track.
What Is RMS?
RMS, or root mean square, refers to the electrical power your audio signal creates over time. The RMS level is important for producers because it combines ideas of perceived loudness with the more easily quantifiable metrics we use to measure amplitude.
Your track will have both a peak and minimum dB level. The RMS value exists between the peak and minimum, with a value closer to 0 dB equating to greater perceived loudness. Shoot for somewhere between -18 dBFS and -14 dBFS when adjusting for RMS. Your DAW's peak meter will likely have an RMS too, but you can also find free plug-ins online that do the job.
Applying Loudness Knowledge in Your Home Studio
Streaming services will subject your song to a process called loudness normalization that automatically bumps your song up or down to the LUFS level it considers optimal for the site. Spotify normalizes audio to -14 LUFS, while Apple Music normalizes to -16 LUFS. If normalizing your track to the optimal loudness level requires excessive compression, your song may sound distorted on the service.
Mixing and Mastering for Ideal Loudness
Mixing and mastering with loudness metrics in mind can give your song a fighting chance in the loudness war. Remember — loudness is mostly a matter of perception, so you should not simply master your audio to Spotify or Apple Music's LUFS standard. LUFS levels of -14 and -16 LUFS are quite low, so mastering at those levels will still result in a final product that is quieter than your professional colleagues. Instead, try some of these mixing and mastering tricks:
- Equalize frequencies: Using an EQ to soften peaks and boost lagging frequencies can help your song feel full before you apply compression or other volume-boosting plug-ins. Everyone loves thumping bass, but too much low end can overpower your mix. Roll back some low frequencies to leave room for your mix to grow.
- Apply a limiter: A limiter will cap your song's dB level at a value you determine. We recommend setting a master bus limiter to -0.3 dB so your track has headroom to accept a volume boost without clipping.
- Monitor true peak: Most loudness metrics take an average of a snippet or your entire song, but true peak looks at the loudest single instance. Listen carefully and watch your meters for spots with a true peak that gets too close to 0 dB or clips.
- Use saturation: Low levels of distortion can make your track seem louder without you adjusting its actual volume. Saturation can emphasize a source's harmonic content, which boosts its perceived loudness.
- Pan effectively: Mixing in stereo and strategically panning each instrument will ensure there's enough space for every element to thrive without canceling others out. A wide stereo mix will automatically sound larger than a mono mix.
Leave Production to the Pros — Focus on Your Art
Learning the ins and outs of loudness is vital for musicians who want to do it all themselves, but great art comes from a collaborative process. Send your stems to an online production service like Mr. Mix and Master so that you can focus on creativity while putting your release's audio quality in good hands.