Achieving a smooth, even bass part in a mix can require hours of tedious automation — unless, that is, you cheat!
One of the more innovative plug-ins of recent years is Waves' Vocal Rider, which can analyse the contents of a vocal track while 'listening' to a cue mix, then generate automation to keep that vocal part at a constant level. The new Bass Rider applies a similar operational paradigm to bass instruments such as bass guitar, upright bass and synth bass. It is protected by iLok, so if you already have an iLok, you can download a demo to try before you buy. Bass Rider is available both as a separate plug-in and as part of the latest (v8) Mercury Bundle, the latter now requiring a second-generation iLok because of the number of individual plug-in authorisations involved! All the usual plug-in platforms are supported (TDM, VST, AU and RTAS) on both Mac OS and Windows, with stereo and mono versions included. No mention is made of when compatibility with the new Avid AAX format will be forthcoming, but news is that those intrepid chaps at FXpansion have already come up with a wrapper to help ease the transition. Up to 24-bit, 192kHz operation is supported, and the plug-in works in real time.
On first impressions, Bass Rider might be mistaken for a compressor, in that it adjusts the signal level in response to changes in the audio input level, but its underlying principle and controls are somewhat different. Level changes are represented as movements of an on-screen fader, as they were in Vocal Rider, and unlike a conventional compressor, Bass Rider is designed to balance the levels of individual notes without changing the note dynamics, adding coloration or altering the individual note envelopes. Of course, if coloration is deemed desirable, you can always use it alongside a compressor!
The standard version of Bass Rider introduces a 42ms latency, so is best used when mixing, but you also get a Live version which adds only 5ms of latency at the expense of slightly slower control of the note attacks, leading to a slight overshoot at the start of each note. Subjectively, in many cases, there's very little difference between the two modes. The main operational differences when compared with Vocal Rider, other than some bass-specific parameters, are that Bass Rider just 'listens' to the bass, not to a music mix as well, and that you can't go in and edit the level automation data, as you could with the vocal version. This, presumably, is because the very precise and rapid gain changes necessary to control bass guitar simply produce too much data. However, all controls other than the auto gain fader can be automated in the usual way.
As with Vocal Rider, there's a horizontal control at the top of the screen that includes a bar-graph display of the incoming signal levels, so that you can set a target level for the process, ideally somewhere around the existing average level. Similarly, there are two sliders for range: one to set the maximum gain increase and one to set the maximum attenuation. A large central fader moves to show you how the gain is being modified, while to the right is an output gain-adjustment fader with a ±12dB range. It is possible to grab the main fader using the mouse, to make manual gain changes, but the plug-in reverts to automatic detection as soon as you release the fader, and, as already stated, can't be automated directly. An Idle arrow sets the fader level for those sections where no notes are detected, allowing spill or amp noise during pauses to be reduced in volume if necessary.
The side-chain's note-detection algorithm is controlled by a Sensitivity knob and a slide switch for Fast or Slow response time: Fast provides better note-detection separation for busy playing styles. Two further knobs to the right adjust Spill and Artefacts. The former allows Bass Rider to ignore low-level spill from other sources (for example, where the bass has been recorded using a mic when other instruments were playing at the same time), while Artefacts adjusts how much the gain is affected by things like finger noise that are not a part of the pitched note.
Waves recommend that Bass Rider is inserted prior to other processing, but my preference is to use a low-cut filter before it, to attenuate any unnecessary sub-bass frequencies. While the bass part is playing, the Target slider can be adjusted so that the loud notes shown on the meter slightly exceed the indicated level. It's also a good idea to solo the bass track, to ensure that all the notes have been detected, and adjust the Sensitivity control accordingly. And that's pretty much it — then Bass Rider just gets on with the job of ironing out level differences between successive bass notes without changing the envelopes of the notes, as a compressor would.
I tested Bass Rider on a number of different bass parts, and although it won't correct the tonal changes produced when a poor player hits notes at very different velocities, it certainly takes the pain out of matching the levels of all the notes in a bass part. There's enough flexibility to avoid over-processing, and unless the amount of spill is unreasonably high, it seems pretty foolproof on note detection. There's also very little subjective difference between the standard and Live modes of the plug-in on a typical bass part, other than a very slight emphasis on the initial transient in Live mode — which can actually improve the sound of some bass parts.
Ultimately, this is a very practical tool that simplifies what is otherwise a routine but tedious manual automation-entry chore, and I can foresee it getting a lot of use.
The only real alternative is to do the fader moves yourself in your DAW and record them as automation.