Wrestling with low‑mid mud? Cubase’s dynamic EQ can help.
Almost every instrument group in modern music productions can contain significant energy in the low mids (broadly speaking, around 250‑500 Hz), so when mixing you’ll often find that there’s an unhelpful build‑up of energy within this range — if there’s too much going on in this region, a mix might sound ‘muddy’, ‘muffled’ or ‘boxy’, and you need a plan to address that.
There are a number of ways in which this ‘too much mud’ issue might be approached, and careful arrangement and instrumentation choices can obviously play a big part, by which I mean you can write the parts and pick and layer your sound sources in a way that avoids an unhealthy build‑up of energy in the low midrange in the first place. But if further control is required, standard EQ applied at the master bus, on subgroups, at the individual instrument level or a combination of all three can be used to control the energy that sits in this frequency range. Cubase offers several EQ tools that can be used for that, including the Channel Strip EQ, StudioEQ and, for users of Cubase Pro or Nuendo only, Frequency 2.
In addition to normal EQ duties, Frequency 2 provides an additional level of control: dynamic EQ. Compared to a standard EQ, where any cut (or boost) is applied all the time, with a dynamic EQ, the cut (or boost) is only applied when the signal is at its loudest in the target frequency range. There are plenty of third‑party options for those using other versions of Cubase (such as Tokyo Dawn’s freeware Nova: https://www.tokyodawn.net/tdr-nova), but since Frequency 2 comes with Cubase Pro and its GUI makes everything really easy to configure, let’s use it to explore some dynamic mud management tactics.
I’ve also prepared some short audio examples (available on the SOS website at https://sosm.ag/cubase-1223) to illustrate what I’m discussing here.
If you think the correction required is a modest final tweak to an otherwise finished mix, or you’re already at the mastering stage of a project, some corrective low‑mid EQ on your master bus or stereo mix might be the most appropriate, or perhaps even the only option. But even if not, I find it’s often worth trying an instance of Frequency 2 on the master bus before you move on to a more finessed approach. You might be surprised by what you can achieve!
The first screenshot shows the settings I configured for this approach with the mix used in the audio examples. Note that I’ve switched the Frequency 2 display to Sing (single band) mode, as this provides easier access to the full range of EQ controls for a single EQ band (in this case, band three of the eight available bands), including the Dynamics section. The required settings will be dependent upon the source material, of course, but there are some useful guiding principles. I’ve used a peak filter centred at 350Hz and with a Q of 2.5 to deliver 9dB of gain reduction. No, that’s not a mistake! A 9dB cut on the master bus would almost certainly be too much with a conventional static EQ band; as can be heard in the audio examples, it would rob this mix of too much low‑mid energy, making the mix sound ‘thin’. But this won’t be a conventional EQ cut...
Before we engage the Dynamics section, though, there are a couple of points worth noting. First, with this combination of settings, the filter shape means the cut extends a little beyond the 250‑500 Hz range. You can control this by adjusting the Q (larger values make the filter narrower) or gain (smaller cuts also reduce the range of frequencies affected by the filter). Second, when you know you’ll be making the band dynamic, it’s actually not such a bad idea to start by applying a static EQ that produces rather more cut than you think you’ll eventually need. This makes it easier to hear the EQ change, and I find it helps when targeting the initial Freq and Q settings; it’ll be that bit easier to hear exactly where the problem lies.
Having brought our ‘mud spot’ into focus, we can now engage the Dynamics section. The main control options are Threshold, Ratio, Attack and Release, and will be familiar to anyone who’s used a conventional compressor before. Again, the settings could vary according to the material, but you probably don’t want the gain reduction to be too aggressive. In the example, I opted for a gentle 2:1 ratio, fast (3ms) attack and medium (150ms) release. With those set up, I simply adjusted the Threshold fader, to specify the signal level at which this band‑specific compression started delivering the amount of gain reduction that my ears suggested was required.
The degree of control is impressive and if you get the balance right, you can tackle the mud without making your mix sound thin.
The GUI provides some very useful visual feedback, and it’s worth noting that the original Freq, Q and Gain settings control the absolute maximum amount of gain reduction that can be applied, while our Dynamics settings control how often and how far the gain reduction moves towards that maximum position. When there’s more ‘mud’ — that is, more energy within the specified frequency band — more gain reduction is applied so, almost as if by magic, the unwanted mud is dynamically managed. You can hear the result in an audio example on the SOS website for which I applied different Threshold settings to adjust the level of mud reduction. The degree of control is impressive and if you get the balance right, you can tackle the mud without making your mix sound thin.
The Start control lets you combine static and dynamic EQ. I’ve exaggerated the settings here for clarity: the Start setting of ‑6dB (topmost thin white curve) forms the EQ starting point onto which any further dynamic cuts are superimposed.Before we move on, a final thing to note about the Dynamics section is the Start control. This allows you to combine your dynamic EQ adjustment with a static cut/boost. So, for example, if I set Start to ‑3dB, I would get a static 3dB gain reduction applied all the time and this would then form the starting point (hence ‘Start’) from which any further dynamic gain adjustment would applied. Again, the frequency display in the upper panel provides a very intuitive graphical representation of this so it’s easy to see what’s happening.
If your usual approach to mixing makes use of the group channels to provide separate sub‑mixes of the drums, bass, guitars, keyboards, vocals and so forth, then you can apply precisely the same basic principles at the subgroup level. Simply insert an instance of Frequency 2 on each of group channel and use each one to dynamically control the lower mids of each instrument group.
In principle, this should give you greater control over how and where your mud management is applied, and minimise collateral damage to sources that you don’t want cut. For example, you could use the approach on just your guitar and keyboard/synth buses (common culprits in mud supplies), while avoiding stealing any lower‑mid energy from other instrument groups. Equally, since you’re dealing with single instrument groups, you can generally be a little more conservative (for example, a higher threshold or lower ratio). Cuts are only applied to a specific instrument when that instrument exceeds the threshold, and when combined with similar cuts being applied in isolation to other channels, the overall result should, hopefully, be a mix with a little more clarity.
By the way, there’s nothing to stop you combining both the master bus and group bus approaches, although if the main mud management is done at the group level, you’ll find you can apply much more subtle settings at the master bus, just to catch the occasional 1 or 2 dB of excess mud.
So, where fader moves and conventional compression and static EQ boosts don’t seem to deliver a satisfying tonal balance (it’s rarely a bad idea to try such bread‑and‑butter tactics first!), looking to these Frequency 2 tactics to minimise the mud can be a great next step. Of course, you could extend the same basic approach down to the individual instrument channel level, though do use your ears to decide if its actually needed — there’s no point processing audio for the sake of it, and if there are complex phase relationships between different sources you should listen out for unwanted side‑effects; unpicking problems you only notice later can be time‑consuming and frustrating!
Another tactic is to use Frequency 2’s external side‑chain input options to duck one or more sources out of the way of a source whose low‑mid presence you want to retain (for example, using the guitar bus to duck a synth bus), but that’s perhaps a topic for another day.
