Have you ever recorded or mixed something, created a bounce, and then went to listen to it on your speakers only to discover it was super quiet compared to everything else? Did this make you feel like you missed something, or like you recorded your music at the wrong volume? If so, I have some good news for you! What you’re experiencing is totally normal, and you probably didn’t do anything wrong. There is a reason why your recording is so quiet. In fact, it's actually not quiet, it’s just that the recordings you’re used to hearing are very loud. You might have googled this and read that it was because your tracks aren’t mastered… Thats nice. In this article, I will explain the ACTUAL reason your tracks are quiet, and tell you how to make them louder.
The Quick Answer
Assuming your main output meters are showing levels close to peaking without actually peaking (if they’re not close, simply turn up your output level!), your track sounds quiet because there is too much of a difference between the volume of the loudest parts and the average volume of the whole song. To fix this, we must decrease that difference.
In order to understand this more thoroughly, it will be helpful to familiarize ourselves with a few fundamental concepts.
Measuring Sound: dBSPL vs. dBFS
Sound Waves (dBSPL)
When a sound wave travels through the air, it literally pushes and pulls air molecules back and forth as it travels. The strength of that pushing and pulling can be measured. We call this measurement sound pressure level, and we express it in decibel units (dB). Average speaking volume is about 60 dB of sound pressure level, or 60 dBSPL. The volume control on your sound system literally controls how much sound pressure the speakers will impose on the surrounding air molecules. For the sake of our discussion, let’s assume these sound pressure levels have no maximum limit.
Digital Signals (dBFS)
When a sound wave is recorded into a computer we get a very different picture. A computer (or any digital device) is only able to represent sound pressure as a number of a finite set of numbers. We call this set of numbers the Full Scale (the full amount of possible values). This means there is a maximum value allowed - a max volume that no sound can be louder than. We call this maximum 0 dB Full Scale, or 0 dBFS. The level of the recorded sound is then a measure of how far below zero it is. If we record a sound that is -20 dBFS, we can always play it back out of our speakers at any sound pressure level - any dBSPL - that the speakers are capable of reproducing.
Peak vs. RMS levels
We can measure a sound at a single moment, or we can measure the average sound level over some amount of time. The latter is of course more useful for describing the overall loudness of a song. The level measured at a single instant is called the peak level, whereas average level measured over some time is the RMS (root-mean-square) level.
Dynamic Range
Dynamic range is the amount of difference between the quietest and loudest sound in a recording. If the most quiet part of a recording is -20 dBFS, and the loudest part is -10 dBFS, then we can say that recording’s dynamic range is 10 dBFS.
Loudness
So far we have established that we can measure sound in dBSPL (amount of sound pressure level), or dBFS (amount below maximum allowed in a computer), and for each of these we can measure the peak level or the RMS (average) level. We also defined dynamic range as the difference between the quietest and loudest parts of a recording. We are now ready to discuss loudness.
Loudness is the subjective perception of sound pressure levels.
The keywords here are subjective perception.
The loudness of your recording is not the amount of sound pressure, and it’s not the amount of distance below 0 dBFS. Rather it is simply how loud we perceive a sound to be. The question then arises:
What factors contribute to how loud we perceive sounds to be?
Humans perceive sound over time, so peak values are not good indicators for how loud a recording will sound. Sound pressure level (dBSPL) can be disregarded for describing loudness in this context, because it can simply be changed with the volume control of the speaker system after the fact. That leaves us with RMS values for dBFS. But this measurement alone is not in itself sufficient to describe the loudness of a song. Other factors that affect how loud we perceive something to be are frequency content - how much lows mids and highs it has, and density - how many sounds are happening at once. dBFS readings don’t take these things into account.
Measuring Loudness
There are software tools available that allow us to measure sound in Loudness Units Full Scale, or LUFS. This differs from dBFS in that it much more accurately reflects a human perception of loudness. If you have a plug-in or DAW that allows you to measure LUFS, use it! If not, RMS values for dBFS are your next best indicator, but in truth, you’ll have to rely on your ears and comparisons with reference tracks.
The Problem
Finally, why are your tracks so quiet?! This problem occurs when your peak levels are approaching 0 dBFS, while the RMS levels are still too low. Since the peak levels are already at zero (the loudest possible), we cannot turn the sound up any more without clipping, yet the average levels are still too low!
The Solution
To fix this, we must turn down the peaks, the parts of the song that are loudest; then we will be able to turn everything else up - at least until the new smaller peaks reach zero again. What we are doing here, essentially, is making the track's dynamic range smaller. There are many ways to accomplish this. Among them, tools like compressors and limiters are the most common. Mastering engineers use a wide variety of techniques including compression, limiting, saturation, clipping, and EQ specifically to make songs louder. This is why people say it's because your track hasn't been mastered! However, a more accurate answer is that it’s because the track has too large a dynamic range.
This does not mean less dynamic range is better!
There is a balance. If you totally destroy all your peaks, your song will lose impact and sound lifeless. If your peaks are too high, your song will appear to be very quiet.
A Quick Fix
Here’s a quick and dirty way to make your track louder:
Add a limiter plug-in to the end of the signal chain on your master track
Set the output ceiling to -1 dBFS (to be safe we don’t hit zero on any inter-sample peaks)
Lower the threshold until your LUFS readings are between -10 LUFS and -16 LUFS, depending on your intended distribution channels.
If you don’t have an LUFS meter, use a combination of RMS level readings for dBFS and comparing your track to a reference track with your ears.
Summary
The reason your recording is quiet is because your peak levels are approaching zero while your RMS values are comparatively low - it has too wide a dynamic range.
Sound volume can be measured as a pressure wave that pushes and pulls on air molecules, expressed in dBSPL, or it can be measured as a value within a set of numbers in a computer, expressed in dBFS, where zero is always the maximum allowed value. These can be considered measurements of level, but not loudness.
Loudness is the subjective perception of sound pressure level. The factors that affect loudness are RMS levels, dynamic range, frequency content, and sonic density. Loudness can be measured with software, and is expressed in LUFS.
The reason your recording is quiet is because your peak levels are approaching zero while your RMS values are comparatively low - it has too wide a dynamic range. In order to raise the level even more, we must first lower the peak level so that we can then raise everything up. It is important not to overdue this, as a lack of dynamic range will suck the life out of your music.
I hope this article has cleared up some of the confusion about loudness. It is my goal to help you create the best sounding music possible. If you have any questions or comments please drop me a line! I’m even happy to listen to your recordings and provide some feedback.
