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Waldorf Rocket

Synthesizer
Published July 2013
By Paul Nagle

Waldorf Rocket

Can Waldorf's new synth rock it? Is it easy on the pocket? We plug it into a socket...

Waldorf's Pulse 2 has been floating somewhere in the ether since its announcement in January 2012, so it was a surprise when, out of a clear blue sky, Waldorf launched the simpler, cheaper Rocket instead. Primarily a monophonic synth with an analogue filter, the Rocket carries a payload of interesting extras that add up to quite a lot more.

Waldorf are keen to draw comparisons with high-end weaponry rather than anything you might find in a vegetable rack. Price wise, though, it's closer to eruca sativa than Trident — and considerably more friendly to share around.

Lettuce Play

Dropping the missile analogies for a moment, there are far too few synths with green paint-jobs, in my opinion, and even though this only extends to the lettering, it's a good start. It's just a pity that the green chosen isn't UV-excitable!

At less than 1kg and just 185mm square, the Rocket is of similar dimensions to Korg's Monotribe and has an equally direct appeal. It's a tabletop box in sturdy black plastic with a layout that's clear and functional. A yellow LED indicates LFO speed and a yellow Launch button doubles as a MIDI indicator. Launch is a convenient way to trigger a note (middle C) with no keyboard connected; once you've played some notes, it switches to triggering the last note received instead.

Thanks to German efficiency, the Rocket is capable of producing a wider range of sounds than its nine knobs and eight switches suggest. The switches all feel great, but a couple of the knobs wobbled ominously on the review model. Strangely there's no main volume control, just a dedicated knob for headphone volume. When space is at a premium, it seems a weird decision to have omitted such a useful control and then added one of far less value. I suppose you have the option to ignore the main output jack and rely on the mini-jack headphone socket instead. Another eyebrow-raising limitation is the lack of fine-tune control, which would have been useful for those occasions when you want to use the Rocket alongside other instruments. It should cause no problems if you're happy with Rocket's A440, but it's not as flexible as it should be. Apparently, I'm not the only person to have pointed this out, and I'm reliably informed that it will be addressed with extra MIDI capabilities in a forthcoming OS update, along with transpose, which is also missing.

If you've run your eyes over the panel already and spotted the Tune knob, award yourself a geek point. However, this knob isn't for tuning the oscillator — it's more exciting than that! Its functionality varies according to the waveform selected and the position of the Wave knob. These controls propel the Rocket from crisp and clear to fuzzy and lush, through many stages in between.

Oscillators

The synth is divided into four sections and, whether you're a novice synthesist or an old campaigner, it's practically impossible to get lost, or make worthless sounds. There's only one way to produce no sound at all, and even that has its uses!

I sensed more than a whiff of TB303 about the Rocket design, from its square/sawtooth switch to its pared-down envelopes. The choice of waveform determines the functionality of the Wave and Tune knobs, each marked with intriguing hieroglyphics. If you begin with a square wave, the first half of the Wave knob's rotation sets the pulse width. At its absolute minimum, the width is so narrow it disappears. Without a level control or mixer, this is the recommended way to deactivate the oscillator, something you'd probably do when using the filter's audio input. Resisting the lure of external processing for a moment, let's keep turning that Wave knob. From 12 o'clock onwards, pulse-width modulation is introduced, the depth gradually increasing until, in the last part of its travel, the modulation speed is also hiked up. That's a heck of a lot of sonic variation squeezed into a single control, but it's typical of the Rocket that it feels 'right' very quickly.

As you can see from the legending at the top of the panel, the Rocket's rear features MIDI I/O, a USB port, audio in and out (on quarter-inch jack sockets) and a 3.5mm headphone socket.As you can see from the legending at the top of the panel, the Rocket's rear features MIDI I/O, a USB port, audio in and out (on quarter-inch jack sockets) and a 3.5mm headphone socket.

Staying with the square wave, the Tune control brings its own innovations. The left part of its travel introduces a copy of the oscillator. At first, this is subtly detuned, but it's not long before all subtlety is dropped. Passing through the middle of the knob's travel and onwards, this newly added oscillator slips into various intervals, such as fifths, octaves and others. In this way, the Rocket covers much of the ground that two oscillators typically would, from the minimum of controls.

Flip the switch to sawtooth and you are treated to a different set of options. At anywhere before 12 o'clock, the Wave knob activates 'Saw Sync Mode' and, with it, further oscillator multiplication. Turning the knob clockwise has the effect of shortening a hidden envelope that's wired to produce sync sweeps. Over the course of its travel, the sweep is gradually reduced to a mere blip, while the Tune control sets the frequency of the slaved oscillator. The end result is a wonderful, zappy and ripping sync implementation that I, for one, didn't see coming.

The interface isn't perfect, though. For example, to select only a single sawtooth oscillator, the Wave knob has to be at its exact centre position. Finding this position isn't always instant, because it only occupies a small proportion of the knob's travel. Still, it's not a great inconvenience. Continue turning the knob clockwise from the centre and additional sawtooth waves are generated: up to eight of them.

The Tune knob operates differently for the sawtooth wave, substituting pulse-width modulation with different intervals and even chords. The number of notes included is set by the Wave knob, and some of the resulting chords are quite complex and interesting. I found that it was often a case of playing it by ear, because it was hard to judge by eye which chord would correspond to each knob position. Actually, with both of these controls it was sometimes more predictable to dial in values from a remote MIDI controller — heresy, I know!

Finally, there's a special sawtooth unison mode that's brought to life when both the Wave and the Tune knobs are at their rightmost positions. All eight sawtooth oscillators are now distributed evenly amongst the notes played. A single key can therefore produce the rich, slightly detuned sound of eight voices layered together. At the other end of the scale, you can play huge eight-note chords. Waldorf are keen to point out that this is paraphony and not true polyphony, because it's only the oscillator that can multiply itself in this fashion, not the filter or envelopes. It's a compromise, but one that worked for synths like the Korg Poly800 and MonoPoly. Being able to switch from an ostensibly monophonic synth to one capable of pads and stabs is a joy not to be lightly dismissed. The final oscillator control is glide and it's activated when you play legato.

Filter

The filter is a 12dB, multi-mode, state-variable design, its band-pass and high-pass modes ideal for classic trance leads or for slimming down the Rocket's pseudo-polyphony. With no discernible zipper noise and a lively resonance, this is a fab-sounding analogue filter. In low-pass mode, it delivers acid bass lines effortlessly from a single saw or square wave, a touch of envelope modulation and the snappy decay. Filter envelope amount is the only Rocket knob driven by incoming velocity, but as this is the optimum setting for accents anyway, it earns a thumbs-up from me.

A rocker switch selects the filter type and a second switch offers filter tracking of zero, 50 and 100 percent. With a setting of 100 percent and resonance pushed into self-oscillation, the resulting sine wave tracks smoothly over at least four octaves; enough for it to count as a sound source in its own right.

Flip the Boost switch and the filter changes from Dr Jekyll to Mr Hyde. This on/off saturation effect is just the ticket for adding bruising harmonic distortion, and although its amount is fixed, its contribution varies with the level of resonance and whether chords are played. It can get quite strange and ugly in the latter case.

Sportingly, the Rocket's filter and overdrive are accessible to external signals, the only proviso being that you must trigger the envelopes with notes or the Launch key. There's no attenuator for the audio input, but line-level signals are handled well enough. Now's the time to select a square wave with a width of zero, assuming you don't want the oscillator splattered all over your audio processing.

Shaping all that filtery goodness into basses and leads, there's an envelope shared by the filter and the output stage. It consists of two switches and a decay knob; attack is always instantaneous. You could view this either as an homage to the TB303 or as an unnecessary limitation, but when I queried if attack could be added later as a MIDI CC, I was told "that's just how it is”. The switches determine whether the release time follows the decay or is zero — happily not a clicking zero like Korg's Monotron range. When both sustain and release are 'on', the envelopes work in single-trigger mode.

LFO/Arpeggiator

At the Rocket's left-hand side are the knobs and switches of the combined LFO and arpeggiator. The LFO Target switch selects modulation of either the pitch or filter cutoff, or engages the arpeggiator. There's not a lot of explanation necessary about either mode. The LFO has three waveforms — triangle, sawtooth and square — and its range is from 0.05Hz to 50Hz. At its very minimum, the LFO effectively stops and generates a random value each time a note is triggered. This isn't quite as desirable as true sample and hold, but it's definitely useful. The LFO syncs automatically to incoming MIDI clock, and occasionally I wished there was a way to deactivate this and let the LFO run freely. At present, the only way to accomplish that is to interrupt clock transmission.

When the Target switch is set to ARP, the arpeggiator is engaged, or should be. The review model wasn't having any of it, despite my sending the appropriate MIDI CCs (in case the switch was busted). It turned out to be a bug preventing the arpeggiator from working unless the Rocket was set to MIDI channel 1. Waldorf are aware of the problem and say that a fix is in progress. The arpeggiator's range is four octaves, and as well as up, alternate and random directions, it has eight rhythmic patterns, some of which introduce glide.

MIDI

Connect the Rocket to a computer via USB and not only does it hurl MIDI in both directions, it draws power too. In a computer-free setup, the same USB cable plugs into a universal adaptor and gets its juice that way. For lovers of traditional five-pin MIDI, the standard In and Out connections are present, but there's no Thru. In order to assign the MIDI channel, you poke a recessed button with a pen while sending MIDI data. The Rocket duly extracts the channel and stores it until you repeat the process.

Almost every control has a documented MIDI Continuous Controller, and not only does the synth respond to these when received, they are also transmitted from the MIDI and USB ports as you turn knobs and flip switches. However, given the lack of a physical volume control, it's odd that the synth does not respond to any volume-related CC. Nor does it offer external control of the Boost or filter Type switches. This seemed to be an oversight because you can otherwise program the entire synth via CCs. In fact, the Type and Boost switches are hard-wired directly and there's no way to prise in any MIDI control, so it's down to the user to manually adjust these two switches.

It's possible to program and store patches via the Rocket Control iOS app, which connects via the Rocket's USB port and an Apple Camera Connection Kit.It's possible to program and store patches via the Rocket Control iOS app, which connects via the Rocket's USB port and an Apple Camera Connection Kit.

Waldorf's Rocket Control iOS app (which can be connected via the USB port and a Camera Adaptor) uses the same MIDI instructions to program and store patches, and provides a handy alternative to hooking the Rocket to a computer.

For ease of use with a computer or sequencer, Waldorf have included the ability (as on their Pulse synth), to transmit a controller burst matching the positions of the knobs and switches. Hold down the Launch button for more than a second and this information is sent via USB and MIDI, for patch storage within a sequencer. Excellent stuff!

Rounding up the remaining MIDI delicacies, there's a hidden LFO with no hardware controls. Intended for vibrato, its speed is set by CC80 and its depth by the modulation wheel. The Rocket also routes aftertouch to the filter cutoff, and pitch-bend is recognised, too, fixed at one octave up and down.

Conclusion

Waldorf have always been a company prone to idiosyncrasies, and the Rocket fits perfectly into that context. Landing when most of us were expecting the Pulse 2, it could be a response to the success of simple, friendly synths such as Doepfer's Dark Energy and Korg's Monotribe. Even though the knobs aren't the most rugged, at this price the Rocket is very attractive, and becomes more so when you take into account the extensive MIDI control.

On a panel where every knob counts, it seems odd to have a volume control for headphones but not main volume. Ditto a glide control but no attack. It's also surprising that nobody noticed the lack of a fine tune or that the arpeggiator only worked on channel 1, but these omissions are acknowledged and, with luck, will be resolved soon. I guess if no weirdness was involved at all I'd be asking what these guys had done with the real Waldorf!

Fortunately, the Rocket's strengths easily outweigh its weaknesses. It's capable of producing far more classic monophonic sounds than its size suggests, all served up at speed. With its sync, pulse-width modulation, super-saw and eight-note paraphony, the powerful digital oscillator is the ideal companion for a quality analogue filter such as this. It's only lack of table space that prevents me from buying one right away, because this is one Rocket nobody would mind landing in their lap!

Alternatives

Other than the drum and synth combination that is the Korg Monotribe, alternatives tend to be more expensive. These include the Vermona Mono Lancet — a superbly-constructed, fat-sounding, dual-oscillator monosynth, although it lags behind the Rocket in feature count and MIDI spec. The same goes for Doepfer's Dark Energy 2: it has solid knobs, patch points, a multi-mode filter and squelchy analogue goodness, but just one oscillator.

Published July 2013