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Arturia Acid V

Arturia Acid V

Arturia have another classic on their long list of software synths: a special little squelchy box.

Acid V is a software emulation of the ever popular Roland TB‑303. With all of the important original features dutifully included, new sequencing, modulation and audio capabilities have also been added.

You may have already noticed the addition of several extra knobs to the front panel. These are for distortion, which makes it easy to jump right into high‑energy screaming acid leads without having to search for a non‑flat 9V battery for that orange Boss pedal; a sub‑oscillator with octave shift and a choice of waveforms; and a vibrato section with depth and speed controls. Vibrato can be assigned to notes in the same way as the traditional accent and glide. Gone, though, is the infamously difficult sequencer, replaced with a grid system that makes the note entering and editing process very easy and offers sequences of up to 64 steps.

Sequencer & Arpeggiator

The interface is nice and clear throughout, although I do hope that with repeated use the silver paint wears off around the cutoff knob as with the original. I was slightly unsure of the glowing green rings around the knobs at first, but they provide a good visual feedback when connected to the various modulation sources.

One slightly bothersome detail is that the ‘Advanced’ button is used frequently to flip between the front‑panel view and the sequencer view, but it’s also the tiniest button, far, far away in the upper‑right corner of the window. It would be useful if there was a keyboard shortcut to flip from one mode to another. One for an update, perhaps?

After locating and pressing the Advanced button you’re presented with tabbed pages for Sequencer, Modulation and Effects. More on the Modulation and Effects in a moment, but first let’s turn to the original 303’s greatest flaw (or greatest asset, depending to whom you speak) — the Sequencer.

Clicking the Advanced button reveals tabs for the sequencer, modulation and effects pages.Clicking the Advanced button reveals tabs for the sequencer, modulation and effects pages.

Acid V’s grid sequencer works much as you’d expect, but has some interesting features including ‘Polymetric’ mode. This allows the number of steps before the end of the loop to be set independently for octave select, notes, slide, accent and vibrato. It’s effectively independent control of the ‘last step’ position for each of those parameters, so that you can set a sequence going where the notes to which slide, for example, is applied drifts over time, to create interesting variations.

The sequencer can be set to adhere to a number of different scales, and it’s possible to enter custom scales (with probabilities set for each note). There is a set of traditional scales, and a set that’s geared specifically towards acid melodies. There’s also the option to fill in the blanks with a pseudo‑random note generator.

The Transmutation section has a pleasing Erlenmeyer flask graphic, which can be used to fill in the blanks to a preselected scale. The range between lowest and highest note is set by the amount of liquid in the flask, and there is also control of Density, ie. the total number of notes that appear in the sequence.

Hover above the octave, slide, accent and other labels and you will get dice icons for further randomisation. Click and drag each die up or down to increase or decrease the likeliness of that parameter being applied to the steps. Dragging a die down to zero is also a quick way to clear the settings on a particular parameter row without having to use the global erase tool. No problem if you erase something accidentally, as an extensive undo history is provided.

There is also a comprehensive arpeggiator, which adds a whole dimension of really fun live pattern generation. It took me approximately five seconds to get this set up with a MIDI keyboard and I spent a lot of time just rocking out playing arpeggiated chords with one hand and knob twiddling with the other. It’s great fun to get the arpeggiator going and then randomise octave jumps and slides, and Polymetric row settings are allowed in this mode as well as in sequencing mode.


Movement is everything with a 303 — after all until Phuture started twiddling the knobs it was just a failed bass accompaniment box. Now it’s one of the world's best‑known synths, and people are even making software copies of it! With this idea of movement in mind, Acid V has three comprehensive modulation sources that can be linked to all of the front‑panel knobs (but not selector switches). Simply drag and drop the cross arrow icon that appears when you hover over the animated modulation graphic within the tab. You may assign two modulation sources to any of the knobs that have a glowing green surround. Double‑click to disconnect the modulation currently assigned to the knob.

Regarding Phuture, I’m sure a lot of you will be thinking, ‘Ah, but MC Turnip Centrifuge got there earlier!’ Just for the record, check the date on Charanjit Singh’s Synthesizing: Ten Ragas To A Disco Beat, and you’ll realise he must’ve picked up his 303 directly from the factory on the day it was released, and started recording during the bus journey home. His album consists of acid tracks from 1982, long before the genre had a name. Admittedly the album is a bit like the Madagascan tenrec, which looks very much like a hedgehog but evolved quite separately.

The three modulation sources can be set as envelopes or LFOs and triggered by key press, note, accent or sequencer restart. There are buttons to select basic modulation shapes and a preset menu for more complex ones, many of which work better as envelopes than LFOs, and you can also draw your own shapes.

The last tab in Advanced mode presents a choice of 17 different effects (in addition to the choice of distortion types on the front panel), with the ability to load a bank of four at any one time. Personally I think the perfect TB‑303 solo doesn’t need a great deal of long ping‑pong delay, but there’s no harm in having the option, and the effects can of course be used subtly. The list of effects includes reverb, delays, compressors, filters, distortion, a bit‑crusher, chorus, flangers, phaser and stereo pan. The effects interface is clear and easy to use, with informative graphics, and doesn’t get in the way of using the rest of the 303. The whole hierarchy of Acid V has in fact been well planned — you can get started quickly but delve into each further level of detail as you wish.

The front panel has a button just above the Acid V logo that activates ‘Trimmers Mode’. When activated a new set of controls pop up, giving the impression the casing has been dismantled to expose the inner electronics. I’ve never seen electrolytic capacitors that size or colour, but we can forgive the interface designers as it’s a nice way of presenting the additional parameters for tweaking, and emphasising that they are non‑standard.

Within this inner electronic area there are little trimmer potentiometers for adjusting a few things including bass boost, the cutoff range and accent attack time, and pitch tracking can also be modified. Ed DMX of DMX Krew has mentioned that his 303 is quite out of tune, with high notes being sharp and lower notes being flatter than they should be, but he likes it like that. So adjust pitch tracking for bonus analogue wonkiness.

Acid V is an excellent TB‑303 clone with a good selection of additional features that encourage exploration.

In Use

Arturia have faithfully recreated the sound of the 303, including the odd thing that it does where turning the resonance right down creates a disproportionately high increase in volume. Note that although the master volume control appears to be missing from the front panel, there is a little dial for this in the top‑right corner. Useful if you want to compensate for the drop in volume when the resonance is turned up.

I set up an identical pattern in Acid V and on the original TB‑303, with no effects, and compared the two side by side. The most noticeable detail whilst attempting to match the two was that the tuning of the original 303 seemed to drift very slightly every time it was restarted. It was also easier to fine‑tune the pitch in software — left‑clicking pitch changes in semitones and right‑clicking any knob gives you fine tuning. The sounds were otherwise very, very similar, certainly within the tolerance of early ’80s analogue components. The cutoff on the original was very slightly more ‘whistley’ when turned fully clockwise, but it’s likely that another 303 would sound different again. I couldn’t find any faults when comparing the two, and anyway perhaps we ought to stop these comparisons and just get on with making some music. Incidentally, simultaneously running the same pattern in Acid V and the hardware 303 with slightly differing tempos immediately created a track that I call ‘Steve Reich Acid’.

Connecting a BeatStep Pro and assigning knobs in MIDI Learn mode was very straightforward, and definitely recommended for ‘head back with eyes closed’ in‑the‑zone filter manipulation. I think potentiometers with physical stops would be better than the rotary encoders I had to hand, but pretty much anything has to be better than the fiddly little knobs on the original. Such an amazing huge sound in such a terrible plastic box!


Acid V is an excellent TB‑303 clone with a good selection of additional features that encourage exploration. Arturia have cleverly not strayed too far from the original silver box, keeping additions like vibrato relatively subtle rather than attempting to turn it into a modular synth. This is definitely about working on cool patterns and then tweaking the sounds, with the live arpeggiator being particularly fun. Another charismatic addition to Arturia’s soft‑synth arsenal.


An accurate and versatile TB‑303 soft synth, with plenty of extras and at a tiny fraction of the cost of an original.


£169 including VAT.