Getting your bass levels right at mix down

As a mastering engineer one of the most common issues with a music mix is the bass levels. Commonly there is not enough bass, far too much bass or uneven response throughout the lower musical octaves. There can be a number of causes for bass level problems.

1)Inappropriate positioning of monitors/speakers in mix room.
2)Lack of acoustic treatment to deal with low frequency energy.
3)Speaker size inadequate to produce full range audio.
4)Low listening volume.

Ideally your loudspeakers should not be positioned in the corners this produces what is known as “bass tip up” or the proximity effect. It means that low frequency sound waves are reflected and appear in phase at the monitoring position. This means you get a bass boost at the listening spot. This can fool the mixer to believe there is more bass present than there is. I suggest trying to keep speakers 1 meter away from walls where it is practical to do so.

The acoustic treatment which is applicable to bass is usually cumbersome and takes a lot of space in a typical studio room. We are speaking predominantly about bass traps. The type most commonly associated with a home studio would be broad band absorptive bass traps. These are usually large quantities of Rock wool mineral fibre or woven fibre glass (Owens Corning) These masses of material allow low frequency energy in to them and stop some of it from re-entering the room through reflection (and thus reaching the listening position). This reduces the presence of standing waves. Standing waves are audio waves which are identical in length to the dimensions of the room. They cause nodes and anti nodes, areas of high and low energy and cause constructive and destructive phase response issues. This makes the rooms low frequency response uneven and difficult to make accurate judgments. Wherever possible install some bass traps in the room, corners are the first places to treat where bass build up is most prevalent.

Small speakers have difficulty in producing the long wavelengths of low frequencies due to their small size. their small size makes them inefficient at producing wavelengths many times their own size. It is suggested that a set of high quality headphones are also used in conjunction with small speakers to get a second perspective on what levels of bass are in the mix down.

In a domestic situation it would be common to listen to music at a lower level than a professional music studio to avoid disturbing occupants and neighbours. One issue that can arise is that the ears own frequency response changes with listening volume. until the SPL (sound pressure level) approaches 80dB SPL the ears tends to be less sensitive to low frequencies in a mix, this can result in a bass heavy mix. You do not have to listen at this level for the entire mix down but it is recommended that you at least listen to a mix at fairly high volumes in order to get a perspective at the ears own flatter response. You can buy a Realistic SPL meter for a low price and this will allow you to understand what 80dB sound like to the ear.

A very good way of estimating the correct level of bass needed in your track is to import a good quality reference in the music style which you are producing. If the track is already mastered (probable) then you can reduce the level of the mastered track in your digital audio workstation and match it to the perceived level of your own mix down session. Once matched you can focus on the low frequency content and eq/ fader balance as is needed to ensure you are in the right ball park in terms of bass content in your mix. 

Barry Gardner is the sole mastering engineer operating SafeandSound Mastering.

An online mastering studio offering high quality at low rates.

As well as working with all types of musical style we are profcient at mastering dance music.

Comments

[Aaron Gibson]

Thanks for the tips Barry! I have learned a lot of these thing by trial and error, or I should say error and error.

[What is mastering]

Hey no troubles, all the best mixing down ! Barry