How to Recover Sub Frequencies

Sub-bass sounds are deep and low-register, approximately below 60 Hz (C2 in scientific pitch notation) and extending downward to include the lowest frequency humans can hear, at about 20 Hz. Human hearing is not very sensitive in this range, so sounds in this range tend to be more felt than heard. Until recently, adding the subfrequencies to an audio source was impossible. But with the development of audio technology, this is now possible and highly useful for various tasks. Therefore, the following tutorial will show you how to recover or add subfrequencies to your instruments.  

Adding Sub Frequencies

As usual, we have previously made a short sequence in the SoundBridge: DAW, which contains all the elements included in a song's full mix. Among these elements is a drone sound, which keeps the tension in the combination. We feel it could sound much better if it had some subfrequencies. Let's hear the drone sound solo as well as the whole mix.  

~Drone - Unprocessed

~Full Mix - Unprocessed Drone  

Submarine by Waves Audio

As you can hear, proper bass frequencies are absent, meaning sub-frequencies below 100 Hz. Let us start fixing that. We will use a sub-frequency generator called Sub Marine, developed by Waves Audio, for this tutorial. Other options are doing the more-less same thing in variable quality, which you are free to explore. Let us look at Sub Marine's interface.  

Waves Submarine is a plugin that enables you to add clean, natural sub-bass content to a signal. It generates subs that are one octave and two octaves lower than the input signal. These generated sub-signals can be controlled further before being mixed with the original signal or sent straight to the LFE bus. You can create bone-rattling subs that highlight the low end of an instrument or use Submarine with a light touch to enhance a sound subtly.  

The Interface

As we can see from the photo above, there are not so many parameters to control. But don't be discouraged by that. Let us go over the main control parameters. You can increase or decrease two sub-generators with variable ranges. Below that, there is a "Range" slider. The generators will use range sets that input signal frequencies to create subs. Use the Max grabber to locate the instrument's fundamental or the frequency that you want to focus on. On the right side of the sub-generators, we can see the sub-effects.  

Drive

Adds a small amount of harmonic distortion to the sub-signal. These even harmonics help the generated subs stick to the original signal.  

Dynamics

Adjusts the compression of the generated subs. It can control how "short" or "thumpy+sustained" the subs feel. Dynamics control affects only the generated subs, not the original signal.  

Mono/Stereo Sub

Sums a stereo-generated sub-signal to mono (stereo component only). Using a mono sub helps to focus the sub energy in the mix.  

Mix

Controls the output mix between the input (dry) and the generated subs signal (wet).   

The output 

It allows you to lower the plugin output gain. Adding subfrequencies will likely add energy to the output signal. On top of that, a dedicated metering section can be seen on the left and right side of the Submarine interface.  

Audio Examples

Once we are done with introducing you to this plugin, it is time to hear it in action. Let us first hear the drone sound processed with the Submarine solo and then in the whole mix. Please keep in mind that in order to listen to the sub-frequencies properly, you will need a pair of decent-quality headphones or proper studio monitors which will accurately present the sub-frequencies.

~Drone - Processed With Submarine

~Full Mix - Drone Processed With Submarine