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Control Synthesis Deep Bass Nine

MIDI Analogue Monosynth By Paul Ward
Published December 1994

Paul Ward suits up, closes the airlock, engages warp drive and boldly goes where no SOS reviewer has gone before...

Fashion is a strange animal. It seems like only yesterday that I was cheerfully giving away my Roland TB303 Bassline because I just couldn't sell it! How times have changed. It now seems that just about everyone and his granny's budgie is desperately chasing a not inexhaustible supply of Roland's cheesy little bass‑o‑matic bleep box. It was, then, perhaps only a matter of time before some enterprising company saw the potential market for a TB303 for the '90s and moved to fill the gap. Enter first Novation's Bass Station, reviewed in SOS July, and now the Deep Bass Nine (love the name, guys!), a single‑oscillator, rack‑mounted analogue monosynth with that all‑pervading form of control that its predecessor lacked — MIDI.

Pre‑Launch Check

We've all come to expect quite a lot from 1U of rack space these days — 16‑part multitimbrality, multiple effects processors, oodles of patch memories and a MIDI specification that reads like a Formula One car service manual. With this in mind, the Deep Bass Nine (or DB9 to its friends) is something of a refreshing surprise. Just 10 controls adorn the front panel; no LCD, no multi‑function controls, no parameter access buttons or alpha wheels. A small red LED to the right of the front panel lets us know that the unit is powered up and a similar LED to the left flashes when a note is triggered. Simple enough so far.

The rear panel does little to complicate matters, although it does contain a couple of welcome surprises. For a start, there is a standard Euro mains connector with integral fuse holder, which is a joy to behold, since it means there's no annoying 'wall wart' or 'line lump' power supply in tow. A pair of MIDI sockets provide In and Thru connections (the DB9 doesn't produce any MIDI data of its own, so a MIDI Out is unnecessary). A single mono output gets sounds to the outside world and a similar audio input allows external sounds to pass through the DB9's filter. For the analogue purist, two sockets connect gate and control voltages from, for example, an old ARP analogue sequencer or an MC202. What I did not expect to see on the rear of this machine was a pair of gate and control voltage outputs. This allows the DB9 to act as a MIDI‑to‑CV converter for an external non‑MIDI synth, such as an SH101 or Pro One. All of the audio/gate and CV sockets are of the standard quarter‑inch mono jack type.

Returning to the front panel, to the left of the rotary on/off switch sits the MIDI channel select knob. Any of the 16 channels are available here, but channel 16 has one further function. On power‑up, if channel 16 is selected, the DB9 will begin to play a demo sequence, which you can halt by switching the selector to any other channel. While the demo sequence is useful as a quick confidence check, it would certainly put me off using 16 as the DB9's normal operating channel!

The eight knobs to the left of the front panel are where the DB9's sound is twiddled, in time‑honoured analogue fashion. Moving from left to right, we first encounter the Waveform control. This can be switched to any one of three positions, giving sawtooth and square waveforms or selecting the external audio input for processing through the DB9's filter. The oscillator has that indefinable 'something' that lets you know in no uncertain terms that you're listening to a true analogue synth; the sawtooth is mean and gritty, while the square wave is agreeably 'synthetic' and, arguably, more suited to throbbing bass sounds.

The 'Tuning' control allows for fine adjustment of the pitch of the DB9's oscillator. There is no octave switching or coarse tuning control with which to quickly transpose the DB9 up or down. This is unlikely to trouble most MIDI sequencer users, as transposition is likely to be a mere mouse click or two away. If the DB9 was used with an analogue sequencer, however, things might prove a little more tricky.

Moving right along, we come across the Filter 'Cutoff Freq' and 'Resonance" controls. The DB9's filter is of the classic 24dB‑per‑octave variety. What this means in less technical terms is that it is very 'squelchy', with all the typically acidic bleeps and blarts that we know and love.

An 'Env Mod' knob controls the amount of modulation imparted to the filter by the envelope generator. This control is responsible for that synthetic 'twang' which is currently so popular, although the degree of control is fine enough to give a subtle punch to the start of a note to simulate bass guitar, for example.

The 'Decay' knob works directly on the filter envelope's decay. I would have liked the minimum value to close right down to a click, but it never quite reached this speed. I also found this control to be biased in favour of the first quarter of its turn, where most of the oft‑used values are likely to be found. An infinitesimal tweak one way or the other made considerable differences — I'd like to see the values spread in a more linear way over the knob's control range. The TB303 (with its incredibly fiddly controls) is somewhat guilty of the same problem, so full marks to Control Synthesis for technical accuracy!

Nothing gives away the intended market for the DB9 more than the Accent control. This allows the Filter cut‑off frequency to be increased by a preset amount on receipt of a MIDI velocity of 65 or greater, and is a derivation of the original TB303 feature. I'm sure that the designers could easily have implemented full velocity control of the filter cut‑off, but this would have compromised the 'authenticity' of the effect for real TB303 purists.

The final control on our guided tour is simply the output volume knob. I found the maximum output level to be on the low side. A couple more dB would certainly not have gone amiss. As it is, the output is clean and clear, though if I wanted to be uncharitable, I might suggest that a headphone output could have been expected.

For anyone who is wondering where the amplitude envelope controls are to be found, wonder no longer, because there aren't any. These parameters are internally preset with a fast attack and release, typical of a 'standard' bass patch. The only exception is decay time which, in addition to the filter envelope, is affected by the front‑panel 'Decay' control

Engaging Sound

So does it sound like a TB303? The short answer is yes. The longer answer is yes, yes, yes! I tried to emulate some DB9 patches on a few of my old analogue synths. The closest I could get was with my Minimoog, which gives you some idea of how gutsy the DB9 is! If you love the sound of the old silver‑clad Bassline, then you're sure to find the DB9 right up your street and sitting on your Mum's doorstep. It bleeps, farts and squelches in a most appealing manner (er, if you know what I mean). And it certainly behaves like a 303 too, especially when accents and glides are brought into the proceedings. By setting a foot pedal to control the glide function and moving a modulation wheel back and forth to modulate the filter cut‑off, I found myself in full control of the DB9 in a way that I could only have dreamed of when trying to program my Bassline through its inscrutable silver buttons. Here's progress at its best! Feeding my trusty K1R through the DB9's filter, I really began to covet this little machine. Though my desire to re‑live the days of the TB303 is perhaps not as keen as some people's, my love of a good old analogue filter is second to none. If I owned a DB9, it would probably live with a K1R permanently plumbed into its audio input!

The DB9 is very firmly aimed at producing good analogue bass sounds and does the job with vigour. The preset amplitude envelope and the lack of modulation options mean that lead sounds and elaborate sound effects are really out of the question, although the synth was quite happy to respond over a generous 8‑octave range, making high 'blippy' sequenced parts possible.

The DB9's MIDI/CV function worked with a minimum of fuss and happily drove both my Sequential Pro One and Roland SH09 (although no S‑Trig option is available for old Moog equipment and the old Hz/Volt system, as used by the likes of Korg and Yamaha, is not supported). Similarly, I had no trouble running the DB9 via its gate and CV inputs from my Pro One's sequencer or a Roland MPU101 MIDI/CV converter.

Do We Have Lift‑Off?

In a way, it's the DB9's solid stand on TB303 authenticity that defines both its strengths and its weaknesses. It's all too tempting to carp and pick at it for not having a brace of oscillators, or for lacking velocity sensitivity, pitch bend or patch memories. But that is really to miss the point of what this unassuming black box is all about. As a dedicated TB303 soundalike bass synth, the DB9 is a triumph. If you are looking for a Minimoog in a 1U rack, then you are likely to be disappointed. This is not to say that the DB9 isn't capable of thundering basslines and chunky sequences, and that, after all, is what the market currently wants. But if you're looking for a lead synth or a spacey sound effects generator, you'd best look elsewhere.

Control Synthesis have, indeed, brought us a TB303 for the '90s. But there are a few imprtant details in which the DB9 is markedly different from its older cousin — it's controllable, rackable, available and affordable. If you're ever in the market for a TB303 then the best thing you can do is let everyone else keep fighting over those little silver boxes and have a listen to this black one. Then start practising your smug expression — in the very near future I think you're going to have need of it...

Switch To Manual

The DB9's manual is written in a friendly (and occasionally humorous) style, with a few example patches provided to get you started. There are also some blank patch charts to record your favourite settings (doesn't that bring back some memories — no pun intended!). With a product as simple to use as this, you might have expected the manual to skim over points that may have seemed obvious to the designers. There are no such problems here, as every control and feature is explained clearly and concisely. There's a description of suggested applications, and even a brief glossary for those new to analogue terms, such as 'gates', 'VCFs' and the like. Very thoughtful of them, I'd say.

Hide & Bleep

Mention should be made of a couple of 'hidden' features of the DB9. Firstly, its filter cut‑off can be controlled over MIDI from modulation wheel commands. This provides an easy way to tweak the DB9 on the fly, and you can record the results into a sequencer for consistently repeatable results. More to the point, it's also great fun! If I was to make any criticism here, it would only be to suggest that the range of control could be wider. Secondly, the DB9 has an implementation of the 303's 'glide' function. This makes notes 'slur' from one to the next by an internally preset time value and is sensibly implemented by MIDI controller 65 (portamento on/off switch).


  • To all intents and purposes the DB9 is a TB303.
  • Good value when compared to the current inflated price of a second‑hand TB303.
  • DB9's filter is available to external synths via the audio input.
  • It's a MIDI/CV converter into the bargain.


  • Relatively expensive for a single‑oscillator monosynth with limited controls.
  • No patch memories or provision for dumping patches over MIDI — paper storage only, I'm afraid!


A simple but extremely effective analogue bass synth. If you really must have that TB303 sound, you could save yourself a lot of hassle by taking a serious look at the DB9.