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Sound Levels and Recording (Part.3)

Author MixCorner 17 January 2020, in - Audio - Dossier - Technique. | 705 visites pour cet article.

Today, third and last part of this serie of articles entitled « Sound Levels and Recording ». The potential impact of recordings based on Peak Levels and not on RMS Levels measurements will be explained.
Morevover, some informations about levels in mastering will be covered too.

Having read the previously published Part.1 and Part.2 constitutes obviously an asset for understanding in depth Part.3.

RECORDING WITH RMS LEVELS

Let’s go back to the Peak Level picture of Logic Pro X (but it could be in any DAW) and the results shown on “Percussions” tracks and will be compared in this particular example with an Electric Bass.

Percussions dynamic vs Electric Bass Guitar dynamic
Percussions dynamic vs Electric Bass Guitar dynamic

Percussive instruments and vocals are the 2 most dynamic types of sources

It can immediately be noticed that meter of the percussions (in this case Afro Cuban Congas) displays a dynamics of about 20 dB FS while that dynamics is restricted to 6 dB FS for Electric Bass Guitar.

What will happen if you record those 2 sources without paying attention to the RMS meters ? Let’s take the hypothesis that you’re going record at – 10 dB FS using the Peak Level meter:

  • Percussions Track : The RMS level of the percussions will be around 20 dB below due to the fact that there is already 20 dB of dynamics, that is around – 30 dB FS.
  • Electric Bass Guitar : When applying the same rationale, the RMS level will be of 6 dB FS below – 10 (due to 6 dB of its dynamics) which results of a value of around – 16 dB FS at RMS level.

The consequence will be that the Electric Bass will sound much louder than the Percussions (- 16 dB FS versus – 30 dB FS RMS). The full explanation regarding how react human ears with regards to RMS Levels is explained in depth in Part.1.

Instead, would you have made using RMS meters, by taking the RMS Level as a basis your recording session, your sources would sound much more homogeneous with similar level.

And believe me, there’s nothing more annoying in a mixing session than having electric guitars that burn your eardrums whilst you can barely hear the vocals... doesn’t it remind you of something sometimes ? ;-)

Recording using RMS Levels meters will bring a more professional aspect to your recording sessions by preventing to get some faders totally down while others being at the highest level.

RMS LEVEL BASED MIXING : SPARE TIME AND INCREASED COMFORT

INCREASED COMFORT

Such a way to proceed will also contribute to a smoother and easier work for the Sound Engineer, because a fader doesn’t have the same distance to move when it is in its starting position and when it is at the very bottom.

Downward the scales are by far much smaller and therefore the slightest variation will generate a difference of several dB that is not the case when the fader is above (see figure).

The extent of the Red area located on the top of the meter allows a 10 dB fader's slide
The extent of the Red area located on the top of the meter allows a 10 dB fader’s slide

The same amount of 10 dB is available on the red area in the bottom; however the range of Fader’s sliding is by far less than the red top area, which add inaccuracies in the level setting process.

SPARE TIME

In conclusion, from what has been explained, ones will immediately understand the advantages of selecting RMS Level meters as optimal tool for professional recording.

Such procedure allows sparing time allover the mixing but especially in the tedious but inevitable « Gain Staging Process » that is in the pipeline to be published soon.

MASTERING

As promised, let’s have a space part of this article for giving information about Mastering

The objective of the mastering process is, in addition to raising the level of the entire songs, to ensure that there is no part of distortion (saturation).

WHAT IS THE APPROPRIATE LEVEL TO LISTEN TO A MUSICAL PIECE ?

As already mentioned earlier, its RMS level will define the volume of a song. During the Mastering, levels will be raised in order to reach similar level as the current music production.

This answers an often-asked demand seen in forums :

  • Why does my Mix sound much less loud than my favorite Record ?
  • And the answer is: because the RMS level is far below the music pieces to which it is compared !

RULE: 0 DB FS AS A LEVEL THAT HAS NEVER TO BE EXCEEDED

Increasing RMS Levels is associated to an increase in the Peak Levels too! However, the Mastering Engineer has to be sure that it never reaches 0 dBFS to avoid distortion. This can be reached using special tools called Brickwall limiters.

Thanks for reading this article. Take care and see you soon

MixCorner




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