Measuring levels：PEAK / RMS / LOUDNESS

There are various ways to measure volume levels.
In this article, we will look at PEAK, RMS, and LOUDNESS.
The LOUDNESS added to Cubase (past 7) in particular allows for a different point of view,
and will be useful in the mixing/mastering process.

Tutorial video

Video key point

First, keep in mind that in sounds and songs, various frequencies are constantly changing over time.

PEAK level

This represents the max that the volume went to in an instant, measured in ”dB”.
As shown below, the highest point of the waveform is the PEAK level.
Almost all DAW level meters have a PEAK level meter included.
Caution：When the sound goes above the PEAK level 0dB, it will clip.

RMS level

Put short, this represents the general signal level.
It is also measure in ”dB”.
It is often used to measure the loudness (sound pressure) of a song.

First, lets visualize just the span of the signal from zero
as shown below.

Just a single point in sound is hard to hear,
so the overall proportional level is measured in RMS.
Caution：When frequencies that are difficult to hear with human hearing are loud, the RMS will show the loudness.

LOUDNESS level

Think of this as the loudness perceived in a song.
There are many ways that its measured, but it uses ”LUFS” in Cubase.
In detail：http://www.jppanet.or.jp/documents/audio_doc/jppa_chair_of_loudness_vol-1_2010.pdf

This depends on the country, but there are even loudness level settings for TV broadcasting.
This is recently true for Youtube, Spotify, and Apple Music as well.
http://productionadvice.co.uk/online-loudness/

Below we have the「equal loudness contour」, which shows how human hearing reacts to certain frequencies.
For example, to feel 1kHz at 60phone we need 60dB SPL, but 100Hz at 60phone would need 78dB SPL.
Hence, even the same volume setting will have a different perceived loudness depending on the frequency.

Now, the importance lies in how to apply this to your music,
but using this knowledge in these situations can prove useful:

• Ex.1)
  When mixing, you want to set the kick drum and hihat to around the same loudness, but each tracks level differs greatly when doing so
• Ex.2)
  When monitoring the RMS level your song with a reference track while mastering,
  you feel the reference track is much louder despite having similar RMS levels
• Ex.3)
  You created club style music that sounds great on headphones and small speakers, but sounded very different when played in a club