The bass part in any track takes on several functions at once. First, the bass line is responsible for the rhythm and connects the drums with the rest of the instruments. Secondly, the bass is the basis of the harmony of the track and the element that is responsible for the movement. And how the sound engineer put the bass into the mix depends on the expressiveness and sound of the entire track.
Music theorists usually divide music into melody, harmony, and rhythm. But the bass is such an important element of the musical fabric that it can be placed in a separate category. We need to make the bass to be a natural part of the mix. But before turning on the EQs and compressors, it’s worth taking a step back and paying attention to the arrangement.
It often happens that due to poor arrangement, the bass does not become an organic part of the song. Pay attention: there are parts in the track that are too low and can be raised an octave; there are parts that duplicate the bass, and which can be abandoned; whether some instruments overlap the bass in frequencies.
The bass is mostly in the 60-200Hz range, and the more other instruments are there, the more difficult it will be to fit it into the mix. And after arranging, pay attention to the tone of the recorded bass and whether it turned out exactly the way you wanted it. To get a convincing mix, it’s best to use reference tracks when mixing. This is the sample track that you will be guided by as you prepare the final audio mix.
Important: the reference track must have the same volume level as the mixdown track. It’s best to measure loudness as accurately as possible using the VU meter found in any DAW. Please note that the reference track should not be processed by effects, so it must be placed on the aux bus.
After that, you can start processing!
Filters are used to get rid of two frequency segments that pollute the mix: below 30Hz (sub-bass if not intended) and around 10kHz. The gain automation can be used to make the bass track smoother in volume. Naturally, the dynamics in the track are needed.
But it should not be so contrasting that there is a feeling that the party is falling apart. Therefore, it is worth making an automation curve, which in quieter parts of the track will increase the gain. Bass parts tend to have a lot of long notes, so the release setting on the compressor should be slow enough that the decay goes along with the end of the note duration.
It is best to match the decay time to the tempo of the track. You can use 150ms as a starting point, or even use the auto-release feature if available. The attack parameter should also be made slower – start with 20-40 ms.
The music style determines whether the kick or bass will contain more low frequencies. For example, Rock music and hardcore are characterized by a punchy bass drum with a click, a fast attack, and little bottom. In Hip-Hop, Downtempo and other sub-genres, you can often find a bass drum with a long sustain and a less sharp attack.
Accordingly, in the mix, the bass will be located above the kick drum – for example, about 100-200 Hz. In any case, do not forget to minimize the overlap of instruments on each other in terms of frequencies.