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SOLID STATE LOGIC Duende

Jul 1, 2007 12:00 PM, By Larry the O

           

The Solid State Logic Duende offers hardware-accelerated plug-ins with the SSL sound.

The SSL Duende is a DSP plug-in host that connects to your computer via FireWire.

Although founded to make solid-state control systems for pipe organs, Solid State Logic (SSL) became widely known for its 4000-series large-format mixing consoles in the late '70s. As the first consoles to include dynamics processing on every channel, and boasting a pioneering automation system, the 4000-series became a studio standard, familiar both sonically and operationally to legions of engineers (myself included).

A great many SSL products have been built on the legacy of the 4000-series. The Duende DSP host is one of these products, though its technology was actually lifted from the company's C200 digital production console.

As the market for large-format music mixing consoles has waned, SSL has branched out into broadcast and postproduction consoles and, most recently, the project studio market. The Duende is intended to bring the famous sound and features of an SSL 4000-series channel strip within reach of the project studio market, and it does so quite well.

Thinking Outside the Box

In order to run the C-series algorithms, the Duende appears in a digital audio sequencer as if it were a software plug-in, following the recent trend of hardware DSP hosts such as the Waves APA, the TC Electronic PowerCore, and the Universal Audio UAD-1 card. The Duende is a 1U device that communicates with a computer over a FireWire 400 port. It supports VST, AU, and RTAS plug-in formats, at sampling rates up to 96 kHz. The front panel has only an AC power switch, while the back panel has two FireWire ports and an input for DC power from the wall-wart power supply.

Because the Duende takes care of the 40-bit floating-point digital signal processing, the minimum system requirements for the host system are not steep: a 1 GHz Pentium 4 or AMD computer running Windows XP SP2, or a 933 MHz Macintosh G4 running Mac OS X 10.4.8. The Duende needs 80 MB of hard-drive space.

Although the device goes easy on your CPU, it takes its toll on the FireWire bus. SSL recommends dedicating a FireWire bus to the Duende, but I say it's a necessity. Note that many computers have multiple built-in FireWire ports that often are all on the same bus, so it is likely you will need to add a FireWire card, which is not expensive but does take up one of the slots in your computer. In certain situations, there can also be some pesky interactions between the Duende and your other computer hardware (more on this later).

A Fine Pair

The Duende comes with only two plug-ins: Channel and Bus Compressor. SSL plans to develop and release additional plug-ins in the future, the first being the DrumStrip drum processor ($299), which should be available by the time you read this.

FIG. 1: Channel’s basic settings are very easy to grasp, and a variety of internal routing options are available.

Channel re-creates the classic SSL 4000 channel strip, with a 4-band equalizer, highpass and lowpass filters, a compressor, and an expander/gate (see Fig. 1). (SSL says the EQ and dynamics are taken from the XL 9000 K-series console, but it sure looks like the 4000 to me.) Bus Compressor is modeled after the 4000-series master bus compressor, renowned as one of those audio devices that just make things sound better coming out than they sounded going in (see Fig. 2).

Both the EQ and the dynamics in the Channel plug-in have a few tricks up their sleeve, nearly all of which are based on the original channel strip. The EQ has two parametric bands and two bands of shelving EQ, but the Bell button on the shelving bands makes them into peaking filters. The 4000 consoles had two primary incarnations: the E- and the G-series. One difference between them was that the E-series EQ had no overshoot, making it more surgical, whereas the G-series had overshoot and undershoot that made it more musical, if less precise. The E button in the Duende plug-in's interface allows you to switch between these two response types — a very nice touch.

FIG. 2: Bus Compressor is -modeled on the 4000 console’s master bus compressor, famed for its ability to pull together mix elements.

The control paths, or sidechains, of Channel's compressor/limiter and expander/gate are in parallel, with the two control signals applied to a single gain element, which presents some interesting processing possibilities. The compressor/limiter has switch-selectable peak or RMS detection, and both parts of the dynamics section have autosensing attack times.

Channel offers an almost complete matrix of routing options: filters before or after EQ, dynamics before or after EQ, filters and/or EQ in the dynamics sidechain, and so forth. Input and output level controls and an input polarity reverse switch complete the module.

The plug-in's interface replicates the 4000's layout and look, which unfortunately is as constraining as it is understandable. For example, Channel reproduces the 4000's 6-LED ladder meters, which were always just a bit better than nothing at all, rather than taking advantage of the computer's graphics capability to show more-informative meters.

Bus Compressor is a totally straightforward compressor, although with stepped attack, release, and ratio controls, and with only three ratios to choose from (2:1, 4:1, and 20:1). It also has an interface that replicates the original, providing a familiar look that is of dubious ergonomics in the digital realm. In the case of Bus Compressor, the issue is the stepped switches, which are changed by clicking-and-dragging — an unnatural and imprecise method.

Both Channel and Bus Compressor can be instantiated as mono or stereo plug-ins. The Duende supports up to 32 instantiations.

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