If you like to get creative with your effects, an ‘envelope follower’ opens up some interesting possibilities. This allows you to use the volume of an incoming audio signal to modulate one or more parameters of an effect. One fairly straightforward (but potentially very useful) application might be to add more overdrive/distortion to louder sections of a bass guitar part than to quieter ones, an effect which can add that extra bit of excitement to a bass without overcooking the levels. The same approach could be used to add an aggressive edge to a lead vocal at certain times.
I’d love to see Steinberg add just such an envelope follower function to the FX Modulator plug‑in. But while we don’t have that yet, a little creative audio routing can help you achieve a similar result — and that’s what I’ll be exploring in this month’s workshop. On the SOS website (sosm.ag/cubase-0423) you can find a few audio examples of the effects described below.
Route Planner
Screen 1: Although the approach described here uses four channels in the MixConsole, the routing involved really isn’t complicated.Let’s start with the electric bass ‘more overdrive when the bass is louder’ example. There are actually a number of ways this might be implemented, including simply configuring the required overdrive/distortion effect as an FX Channel, routing a send from your bass source track, and then manually automating the blend between the clean and overdriven signals to add more overdrive at the required spots along the timeline. But if a more automatic solution in the style of an envelope follower is wanted, the audio routing setup you can see in the first screenshot provides another option (Screen 1).
I’ve used four channels to do this, but hopefully the routing involved is still pretty easy to follow. On the left, the Bass Org audio track contains the original clean bass guitar recording. Next to this is an FX Channel named Bass Overdrive FX, with an instance of DaTube inserted. We then have two Group Channels: Bass Bus Clean and Bass Bus Blend. The output of Bass Org is routed to Bass Bus Clean, but also has a Send routed to Bass Overdrive FX. The outputs of both Bass Bus Clean and Bass Overdrive FX are then routed to Bass Bus Blend, where the clean and overdriven parts of the sound are recombined before being passed on to the project’s stereo master bus.
Expand On That
So how does this routing configuration then let us perform our overdrive trick? Well, if we insert a dynamics plug‑in prior to DaTube on the Bass Overdrive FX channel, we can modify the level of the input signal that reaches DaTube based on the level/dynamics of that input signal. For example, if we set up a standard Compressor instance here to bring down the louder sections (and don’t apply makeup gain!), less of the bass signal will reach DaTube at those times, so there’ll be less overdrive in our final blend. This would be the opposite of what we’re trying to achieve, though! So instead we’ll use the Expander plug‑in (shown in the screenshot).
With a downward expander such as this, when the signal is below the threshold it’s turned down by an amount determined by the ratio, while signals above the threshold are left untouched. The result is that the dynamic range of the signal is increased, or ‘expanded’ — hence the name of this processor. Placing Expander before our parallel overdrive, then, allows us to exaggerate the dynamics within the bass performance, so that when the bass is played more softly less of the signal reaches DaTube. This results is less distortion during the quieter parts and, relatively, more distortion in the louder passages.
It’s worth noting that this is not exactly what you might achieve with a volume‑based envelope shaper, because in that case, the resulting envelope could be used to modulate a specific parameter (for example, the Drive control) of the target plug‑in, rather than just modulating the send level. But in the absence of an actual envelope shaper tool, it’s a very useful alternative — and, in this case at least, can produce a very similar sort of result. Screen 2 shows the Expander settings I used for this example, but you can experiment with different threshold and ratio settings to finesse the dynamics of the overdriven signal.
Screen 2: Expander determines how much signal reaches DaTube, while adding Gate and StudioEQ into the side‑chain gives you further ways to shape the effect.
More Options
If you would like to ensure that no overdrive at all is applied to the lowest‑level parts of your bass guitar signal, you can simply place a Gate plug‑in before Expander. In the screenshot example, I’ve set fast attack, hold and release settings, but you should feel free to experiment. The most important parameter is Gate’s threshold. When the signal exceeds the threshold level, signal passes to Expander to give us the same effect as described above. But when the signal falls below the threshold, no signal will be passed to the Expander (or onwards to DaTube), so there will be no overdrive effect.
You can add further flexibility by placing an EQ plug‑in after your overdrive/distortion effect. In this case, I’ve used an instance of Cubase’s stock StudioEQ. Three bands are active, with low‑end and high‑end cuts applied and a peaking filter (band 2), centred around 2000Hz, used to add gain. This means that the output from this track (the overdriven version of our bass) is focused on the mid/upper‑mid frequencies. The idea here is to add a little high‑end definition to the overall bass sound, but leave the bass’ low end sounding clean, clear and free from distortion. This is, of course, a matter of taste and musical context, and you could try different settings, but it can certainly be a useful option to further tailor/control the final effect.
Level Headed
In all the examples I’ve outlined so far, both the clean (Bass Org) and overdriven (Bass Overdrive FX) components are combined at the Bass Bus Blend channel to create our ‘composite’ bass sound. Electric bass is usually compressed (in most genres, anyway), and a final dash of compression can be added here to even things out a little. In Screen 3, you can see an instance of Compressor inserted on this Bass Bus Blend channel, and this might be all that’s required. But do keep in mind that more of the overdrive element is added as the clean bass signal itself gets louder. When active, our ‘dynamic’ overdrive might, therefore, deliver a noticeable jump in overall level for our Bass Bus Blend compressor to deal with.
Screen 3: With the routing described in the main text, you can also choose to ‘duck’ a clean bass signal when the overdriven component is at its loudest.
Our Bass Bus Clean track, in which the clean bass signal is passed through on its way to the Bass Bus Blend channel, offers a way to tame those potential jumps in overall level. In this case, I’ve achieved that by placing a compressor on the Bass Bus Clean channel. It is responding to an external side‑chain signal, taken from the Bass Overdrive FX channel. This way, when the overdriven signal increases in level, this compressor reduces the level of the clean signal but only after the clean signal has itself triggered the overdrive. The result is a more even level when the clean‑plus‑overdriven blend arrives at the Bass Bus Blend channel — the compression settings allow you to finesse this to achieve the desired result.
One extra detail is worth consideration. Having used StudioEQ to frequency‑limit the overdrive (in this case, within the 500‑5000 Hz range), the additional level this overdrive component adds is only within the frequency range. However, the side‑chain‑driven compressor on the Bass Bus Clean channel applies compression across the full frequency range of the clean bass signal. As a consequence, louder sections of overdrive centred at 2000Hz may well trigger gain reductions above and below this, and this risks robbing the composite sound of its low‑end solidity. You can replace the Compressor instance on the Bass bus Clean channel with Cubase Pro’s Frequency 2 (users of other versions can use another dynamic EQ plug‑in) and trigger a dynamic band to ‘compress’ just the required frequencies in the clean signal, to match those frequencies that are added in the overdriven channel. Hey presto! Your low end will remain intact.
And There’s More...
Of course, you don’t have to restrict this kind of experimentation to just bass. For example, the same trick can also be quite effective on a lead vocal, adding some grit and a good dollop of attitude to the louder sections of a performance; I included an example of this in the online audio clips. Equally, the same approach can be used with different effects types. For example, you could have more flanger on your guitar as it gets louder. If you swap out the Expander for an instance of Compressor, you can also reverse the process and get more of an effect in the quieter parts of a performance (more reverb on the quieter sections of a piano part, perhaps?). And, finally, don’t be scared to try these effects on the input signal as you play — you can have great fun adjusting your playing dynamics to hit the effect ‘sweet spot’. While I’d love Steinberg to add an envelope follower into the Cubase feature list, there’s already plenty of fun to be had with this kind of creative audio routing. Enjoy!
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