Siegfried Kullmann recently released version 0.81 of SQ8L, a software model of Ensoniq's classic 1980s synth SQ80. The SQ80 features 3 digital wavetable oscillators for each of its 8 voices which are fed through analog 4-pole lowpass filters (-24dB gain) with resonance. Sound parameters can be modulated by 4 envelopes, 3 LFOs and several MIDI sources. The SQ80 also has a predecessor, the ESQ1, which can do most of the same stuff.

Although the technology may seem obsolete, these synths can produce a wide variety of interesting and extremely usable sounds. Thanks to the lo-fi oscillators and the analog components it can sound very digital and dirty, but also very analog and warm. Which is a good thing because modern synths often tend to sound rather clean.

The SQ8L ("L" stands for "Light") is the free demo version of the forthcoming SQ8X ("X" for "eXtended"). Besides any bugs that will be fixed in the full version and planned features that won't find their way into the light version, there are only a few limitations:

• Polyphony limited to 8 voices.
• Program change messages ignored.
• Common MIDI controllers (Master Volume, Pan,...) by default have no effect and must be programmed as modulators.
• When used with a sequencer, the only sound the host can save within the song file is the one in the edit buffer. The full version will store the entire library (which makes sense when program change messages are used).
• LFO humanization not implemented.
• No Split/Layer to combine several sounds.
• No internal sequencer (and there will never be one).

The full version SQ8X will have the following additional features:

• Combinations of up to 4 single sounds.
• Adjustable polyphony (far more than 8 voices).
• New Filter algorithms with different modes (lowpass, bandpass, highpass).
• 2nd Filter and different routing modes for the filters: serial, parallel, split.
• Improved GUI.

SQ8L version 0.81 is currently available as a free download as a VST instrument for Windows.