- Who doesn't want more bass? As far as common rhetorical questions go, this one's right up there in the world of electronic music production. In fact, it's a question that's been unnecessarily asked since the '70s. Fuelled by a desire to pump up the kicks and basslines of the exploding disco revolution, dbx created Subharmonic Synthesisers. These rack-mounted hardware processors listened to an incoming low-end signal and created a new, Waveform Modelled bass note one octave below the original, resulting in a fatter, heavier sound. It's a patented technology that has remained largely unchanged ever since. Now Brainworx, the German company renowned for its industry-leading Mid/Side processing plug-ins, has created bx_subsynth, a plug-in modelled on the original dbx 120XP Subharmonic Synthesiser.
The 120XP has two frequency ranges of operation, 26-36Hz and 36-56Hz. The bx_subsynth has a third, higher band, and a total range of 24Hz to 80Hz. This extra reach can help add weight to snares and higher-register basslines that would not have been possible with the hardware model. The three bands are fed by trim controls that boost the level feeding into each band. This allows for a fuller and more rounded synthesis output, which is mixed in via the Subharmonics control above.
Given that it's something of a Brainworx speciality, it was inevitable that Mid/Side processing would be included. Essentially, there are two different synthesis engines within the bx_subsynth that can be selected with a switch that slides between a Mid/Side or Stereo setting. If you're working with drum, bass or buss groups containing a range of material, then you'll want to go for the the Mid/Side option. In this mode, only the mid signal feeds the subharmonic engine, omitting any stereo information. This is fairly essential when preparing tracks to be cut to vinyl or for getting a clean separation between the low-end and higher frequencies. Stereo mode would be useful for the processing of effects where it's okay for low-end information to exist in the sides of the stereo field. In certain cases, it would also work on something like a bass synth, though this may require some additional processing for it to sit correctly in the mix. But for most electronic music production, the Mid/Side option works best.
Another classic Brainworx feature is found in the Mono Maker. Lifted from their renowned bx_digital mastering EQ, it's a simple control that sums everything under a user-defined frequency into a mono signal. Handily, this covers the full frequency range so it can be used to check the mono compatibility of the entire mix at its highest setting. A more common use case would be working with hardware drum machines. Say you record a pattern from a drum machine as a single stereo file. You could then use the Mono Maker control to mono just the frequency range that the kick occupies. It's so useful that you might use this feature without touching any other parameters. It's also paired with a stereo width control that increases the perceived width of high-end material by up to 400%.
On the other side of the plug-in are the Edge and Filter sections. The Edge section works in parallel to add saturation and compression with its Squeeze and Drive controls, reducing dynamic range and increasing overall perceived volume respectively. Low and High Cut filters help to sculpt the results. This pushes the plug-in toward more creative sound design possibilities, though in my experience these controls tended to produce some rough, unwelcome artefacts. Other plug-ins, such as MaxxBass by Waves and Universal Audio's Audio Precision Enhancer Hz, work in a similar way. By adding higher harmonic frequencies, they help accentuate the bass tone, allowing it to cut through the mix and stay present on smaller speakers. I found these plug-ins to be smoother and more natural than the bx_subsynth, though with a subtle hand you can fashion some decent results.
Finally we come to the Filter section. The Tight Punch knob is a sixth-order Butterworth high-pass filter with a resonant peak, designed to filter out unwanted low-end frequencies while providing a boost at the resonant frequency, resulting in a tighter, sharper bass tone. Despite it's inclusion at the bottom-right corner of the plug-in window, it's work actually takes place at the start of the signal chain, after the gain input. Next is the Low End control, which provides a boost at around 55Hz. It enhances the overall bass output after the subharmonics have been summed in but before the Mid/Side and Edge sections have been implemented. These two functions actually work independently of the subharmonics synthesis and are available in the free bx_subfilter plug-in.
There is something of an accepted method to setting up the bx_subsynth correctly. After dialling in the Tight Punch filter knob and setting the lower edge of the frequency range you wish to work with, audio is fed into the central subharmonic synthesis section. Here you adjust the trims of each band until the white LEDs show that they're receiving enough signal. Then you mix the three bands to taste before blending them into the original signal with the subharmonics master control knob.
In the example below I've written a rough acid line. Although tonally aggressive, it's firmly rooted in its middle and upper frequencies and could benefit from some overall weight to beef it up.
After inserting the bx_subsynth, I went through the basic procedure outlined above, avoiding the other controls to concentrate purely on the strength of the synthesis engine. The 24-36Hz knob remained at 0% as there was no information to work with that far down the frequency range, despite cranking the input trim as far as it would go. 36-56Hz was set at 62%, with the 56-80Hz knob at 66%. These were then mixed in with the master control at 78%. Instantly, a warm and rounded sub bass tone has been added, thickening the weak original into something much fuller. The result is also, to my ears, more natural sounding than the classic approach of inserting a sine wave that follows the pattern of the original bassline. It also avoids the tedious process of trying to match up the original's notes if you're working with audio samples and not self-programmed MIDI.
In some instances however, not every note will be caught by the bx_subsynth's input and translated into a lower octave sound. Those sounds with no frequency information at or below 160Hz will be skipped over by the synthesis engine. While this may create some disconnect between the original and the synthesised bass, it could also be used creatively. For example, you could bounce and low-pass the processing of the bx_subsynth, thereby creating a unique but harmonious bassline with some shared characteristics of the original source. On that note, it would have been nice to have access to just the subharmonic portion of the sound without the original.
The following example shows how the bx_subsynth can be used more creatively to change the tone and style of a drum track. I've programmed a simple 909 beat with some gentle saturation, a short delay and a little high-shelf EQ to bring out the some of the percussion, and placed the bx_subsynth on the drum group's buss.
Now all three frequency bands have been used, with the 24-36Hz knob at 25% to bring out some of the very low-end, while the two higher knobs have been left as they were in the previous example. The Mono Maker has been turned up to 145Hz to ensure the kick and the lower frequencies of the snare are working straight down the middle, while the Stereo Width has been increased to 150% to catch some of the delay and scatter the tops of the clap slightly. Most of the design work takes place in the Edge section, with Squeeze pushed all the way to 100% and the Drive up to 60%. This might seem fairly drastic, but by narrowing their field of influence with the high and low cut filters, we've not just tightened up the low-end through the synthesis engine but bought the whole drum track together, resulting in a sharper, more focused sounding beat.
However, some EQing is required to avoid overlapping frequencies and potential phasing issues between the two tracks. The acid line in the above example needed some fairly hefty sidechaining against the kick to get it to sit in the mix, though the benefits of the bx_subsynth on both elements were still readily apparent.
While the bx_subsynth is not unique, none of its competitors match its flexibility and smoothness of tone. The natural quality of its bass production is where it excels. While I would avoid the more extreme settings found in the Edge section and would appreciate some control over the resonance found in the Tight Punch control, what this plug-in sets out to do, it does very well.
Ratings:
Cost: 4.0
Versatility: 3.3
Ease of use: 4.2
Sound: 4.5