Over the past few years, that beloved classic acid sound has seen a revival of sorts. With it comes the demand for new ways to twist and contort that good old 303 sound.

However, most of you probably are not one of the brave few with the funds and knowledge to crack open a vintage 303 and circuit bend it beyond its original capabilities.

That’s where Swedish software developers AudioRealism step in.

First developing their Bass Line virtual instrument, a direct emulation of the 303, now comes the Bass Line Pro, a next level soft synth which goes far beyond the concept of the original 303.

Audiorealism’s Bass Line Pro (ABL Pro), a monophonic/polyphonic semi-modular synthesizer with an integrated pattern sequencer powered by its two voltage controlled oscillators, packs a ton of features that allow it to generate not only authentic acid sounds, but a vast sonic palette of leads, pads, basses, organs, fx, arps, drums, sequences and more as demonstrated by its more than 500 included factory patches.

So if acid’s not your thing, the ABL Pro’s sound design capabilities will have a lot to offer any style of music.

The ABL Pro’s synthesizer section boasts a powerful collection of modules. Along the top of the interface, you can control the overall volume, shape and boost. The mixer section allows you to mix up to four audio elements: oscillator 1, oscillator 2, noise and auxiliary input which allows you to run other instruments or samples through the ABL Pro’s filters.

Each of the two oscillators have five waveforms: sawtooth, square wave, pulse, triangle and sinus. The modulation generator routes various shaped waveforms to several destinations.

Also with the appropriate settings that are outlined in the manual, you can use the modulation generator as a third oscillator. The built-in stereo delay unit has a very analog sound to it and allows you to add that touch of delay when you need it.

The ABL Pro has three filter modes. A 24db self oscillating mode gives you a similar feel to the 202 or 303.
The integrated pattern sequencer — directly inspired by the 303 — allows you to program your patterns directly on the synth itself and allows you to program up to 64 step patterns. You can then store up to 127 varying patterns in a single patch.

Each pattern can then be triggered by a different midi note. You also have the option to switch from pattern to note mode which will give you more traditional control over the notes and bypass the integrated sequencer.

Furthering its capabilities, the ABL Pro allows you to import and export your patterns via a small text file. If programming in a text editor is your thing, you could even write your patterns in a simple text format and import them into the sequencer.

If you’re a user of Rebirth, you can also import your old Rebirth patterns in the pattern sequencer.

The intuitive and powerful patch cord feature gives you the sound design modulation capabilities of modular routing.

The ABL Pro’s interface has a number of voltage processors that are used to shape the control signals. With them, you can control the attack, release, smooth, invert and scale the envelopes.