SOLID STATE LOGIC DUENDE

Oct 1, 2006 12:00 PM, BY ART VANDELAY

Without a doubt, this is one of the most exciting products of the year. Who would have thought we'd see the day when you could buy an authentic 32-channel SSL mixer for less than two grand, let alone seamlessly integrate it as a plug-in with your digital audio workstation (DAW)? Served up on a custom DSP platform, Duende is a powerful rackmounted solution that connects to a VST/Audio Units/RTAS workstation host through a single FireWire cable to deliver console-grade channel-strip EQ and dynamics, as well as the legendary SSL stereo Bus Compressor.

CERTIFICATE OF AUTHENTICITY

Various online forums entertained heated discussions over whether Duende is merely another SSL channel-strip emulation (along the lines of the McDSP Channel G, URS S Series and Waves SSL 4000 Collection) or if it is, in fact, the real deal. Whereas the aforementioned trio based their arm's-length emulations on the classic SL4000 analog console from 1977, Duende's brains are quite literally lifted from the SSL C200 digital production console. Interestingly, the C200's algorithms were modeled on the company's XL9000K SuperAnalogue console, which was released in 2002 and has since become the quintessential large-format desk of choice for pop and hip-hop producers and mix engineers around the world.

Duende is a direct descendant of SSL's proven digital technology based on the sound of its latest analog lineage. And since this is Solid State Logic virtualizing its own gear, you know the company did it right.

Duende boasts a quartet of dazzlingly powerful 333 MHz 40-bit floating point SHARC DSPs—individually more powerful than those in the C200. The 1U-rackmount box is weighty and solidly built with a faceplate appearing to be made of silver-fleck-finish cast aluminum, sculptured to a soft bulge that looks slick. Despite its mass, Duende doesn't have an internal power supply; instead, it relies on the included universal wall-wart adapter with snap-in prong plates for globe trotting to different countries. However, Duende can also receive bus power via the 6-pin FireWire port around back. The bright white ring of light surrounding the power button lets you know if the juice is flowing sufficiently.

FIRE UP THE BANDS

Only the Mac version was shipping in time for review, but according to SSL, PC support should be ready around the time you read this. Installation was simple and straightforward with no authorization required; the hardware unit acts as the dongle. First, mono and stereo versions of both the EQ & Dynamics Channel Strip and Bus Compressor get placed into three plug-in format folders: VST and Audio Units versions coded by SSL and an RTAS version wrapped by FXpansion.

During the review, SSL released a software/firmware maintenance update on its Website. My early unit didn't ship with any presets, but signature sets will be available shortly on SSL's new Mixbuss.com site. There is also a well-written and thorough PDF manual.

Duende has been tested to work with a wide assortment of PCI and FireWire audio interfaces, though three popular models are not compatible: Focusrite Saffire, M-Audio FW410 and the PreSonus Firepod. SSL recommends using the following DAW versions or higher: Logic Pro 7.2, Cubase SX3, Nuendo 3, Live 5.2 and Pro Tools HD/LE/M-Powered 7. Unfortunately, Digital Performer is not currently supported, but a compatibility fix is in the works.

You can run Duende plug-ins simultaneously with other host-based or external DSP plug-ins in any combination, but there is a theoretical limitation to the overall flexibility at hand—even aside from crucial latency and FireWire bandwidth issues detailed in an extra “Bandwidth and Latency” section available at remixmag.com. Duende has a total of 32 slots available simultaneously at sampling rates of 44.1 kHz or 48 kHz (this halves to 16 slots at 88.2 and 96 kHz), each capable of running either channel strips or compressors. Every mono channel-strip plug-in takes up one slot, and a stereo strip or stereo compressor takes two. Should your session call for three stereo Bus Compressors, for example, you'll be left only 26 slots with which to fill using any combination of mono or stereo EQ and Dynamics Channel Strips.

In other words, Duende can only be a 32-channel mix processor if you run no compressors and your session is 48 kHz or less. A preferences panel shows the driver and firmware versions and the Duende hardware serial number, how the slots are being allocated and if the unit is connected and functioning properly.

BANDWIDTH AND LATENCY

Tested Duende on my Mac dual 1.8 GHz with 4 GB RAM, OS 10.4.4 and Pro Tools|HD 3 Accel hardware with a 192 I/O interface, I ran Duende as RTAS under Pro Tools HD 7.1 and as Audio Units under Logic Pro 7.2. My audio drives were on the front-side FW400 port of the G5 while I plugged Duende into the backside FW800 port, hoping that it might be on a separate bus. SSL nor Apple would confirm any advantages to this, but when I tried running a maxed-out Duende session with 28 mono channel strips, two mono group compressors and a stereo bus compressor—plus streaming about 50 tracks from disk—everything played along nicely with not a single click or hint of FireWire bandwidth being taxed.

I strongly suspect that part of this working so well is the fact that I was not using FireWire for audio I/O (Pro Tools HD hardware is directly on the PCI bus). With all three PCI slots taken up in my G5, a FireWire PCI card isn’t really an option, so it's great that it works without one. And, early reports also indicate that Duende plays well with other DSP solutions, including all combinations of PCI and FireWire TC Powercores and Universal Audio UAD-1s. I’m also happy to say that Duende doesn’t seem to pose much of an idling hit to runtime CPU resources, though the kernel task does go up about 20-percent.

Now, latency is of course an issue with all DSP platforms, and Duende is no exception. It is a result of audio having to go off the CPU, down the bus, out the FireWire port, into Duende, wait for its number crunching to occur, and head back up the Firewire to the CPU. Contrary to popular belief, it should be noted that the RTAS wrapping process has absolutely no affect on latency.

Duende’s latency is most definitely audible, but it does report it exactly to the host for automatic delay compensation (ADC) and sample-accurate playback. Pro Tools LE does not feature ADC, so you’re left having to manually compensate or use Digi’s sample-delay plug. And, while mixing is obviously Duende’s intended use, monitoring live inputs or performing overdubs will inevitably contain delay. I’d love to see a “kill” button in Duende’s preferences that would temporarily bypass the plug-ins wholesale in these instances, similar to the UAD-1.

Of note, v.1.2 adds a Bypass All button within the Duende channel plug itself, allowing all of its signal processing to be bypassed while remaining active in your plug-in chain. This lets you A/B settings without introducing latency glitches caused when you use the bypass button of your host.

The update now supports the Freeze function in Logic 7.1 or greater, Cubase SX 3 and Nuendo 3; however, bounce will always remain a real-time process, and freezing will not free up any of Duende’s resources. Lastly, the update also quelled my early complaint that parameter values weren’t displayed upon alteration or mouse-over.

CHANNELING A HIT

The equalizer of the EQ and Dynamics Channel Strip is 4-band parametric based on the XL9000K circuits featuring two distinct EQ curves. The normal curve is SSL's G series shelving EQ, which has a degree of overshoot/undershoot (depending on whether you're boosting or cutting) below the selected high frequency or above the selected low frequency. The LF (low frequency) section operates over a range of 40 to 600 Hz and is capable of a maximum ±16.5 dB gain. The HF (high frequency) section covers 1.5 to 22 kHz and is capable of ±20 dB. On both bands, you can choose from shelving or peaking curves by pressing the Bell button.

The LMF (low mid) ranges from 200 Hz to 2 kHz, with an adjustable Q of 0.5 to 2.5 and ±20 dB of gain. The HMF (high mid) ranges from 600 Hz to 7 kHz, with the same adjustable Q and gain. Such aggressive settings make for meaty mids—great for sculpting electric guitars and searing vocals. It even nails how the G type EQ models the pre-boost dipping as you narrow the Q and raises the gain as you make the Q wider. This compensation occurs automatically and is a distinctive trademark of the G EQ.

Engaging the E button, based on the latest version of SSL's classic E series EQ, removes the overshoot/undershoot effect of G type and provides a slightly gentler slope with the bandwidth of the HMF and LMF sections remaining constant at all gains. At lower gains, the EQ curves are comparatively narrower for a given Q setting, which is particularly useful for drums because relatively high Q is available at low gain settings. Having both E and G EQ types switchable on the same strip as integrated dynamics gives Duende an immediate leg up on the Waves SSL collection, which offers G series as an EQ module outside of the strip.

By default, the EQ precedes both the filter and dynamics section, but you can rearrange those with great flexibility. Pressing the Input button sends the 12 dB/octave lowpass filter (20 to 500 Hz) and 18 dB/octave highpass filter (3 to 22 kHz) pre-equalizer. Each filter, as well as the EQ section, may be independently bypassed or dynamics sidechained, or you can pop the filters into the sidechain together with EQ for simple de-essing and other frequency-controller dynamics processing. If only the filters are assigned to the sidechain, the EQ comes before them in the signal path. A block diagram at the bottom of the plug-in window always shows you clearly what's going where as you make routing adjustments.

The dynamics section features a compressor/limiter and expander/gate that work independently but can be simultaneously operational. Like its hardware counterpart, this section can be placed before or after equalization (but always appears post-filters), and makeup gain is automatically applied to maintain steady output levels. The compressor has a continuously variable ratio from 1:1 to Infinity:1 (limiter), threshold from —20 dB to +10 dB with auto-sensing attack time (or selectable 1 ms Fast Attack time) and a variable release from 0.1 to 4 seconds. Switchable soft-knee RMS or hard-knee peak provide two modes of signal detection, while a 5-segment yellow and red LED meter shows gain reduction. The adjacent gate/expander section features a variable attenuation Range knob of 0 to 40 dB; variable Threshold of —30 dB to +10 dB; fixed 1.5 ms attack, switchable to Fast Attack; variable Hold knob of 0 to 4 seconds; and a Release from 0.1 to 4 seconds.

The v.1.2 update introduced 20 dB of input gain/attenuation with phase reverse and metering. A similar Gain knob and level meter is provided on output, as is an S/C Listen button that routes the sidechain directly to the output for monitoring.

THE GREAT COMPRESSION

The Bus Compressor plug-in, though modeled on the unit within the XL9000K, roots back to the SL4000 and is largely what makes the SSL experience so captivating. The familiar interface features a large VU meter expressing gain reduction in analog dBu rather than digital dBfs, though I didn't find its visual needle response as smooth as it could be. In fact, the entire graphical user interface of the plug-in feels unnecessarily oversized for the number of controls present. These include a continuously adjustable Threshold (±15 dB), Attack (six switchable rates: 0.1, 0.3, 1, 3, 10 and 30 ms), Ratio (2:1, 4:1 and 10:1), Release (0.1, 0.3, 0.6 and 1.2 seconds or automatic) and a continuously variable Make-Up gain ranging from —5 dB to +15 dB.

The beauty of this compressor is its simplicity and effortless grace. Used subtly, it can effectively control the dynamics of drum overheads or whole drum kits, or glue together an entire mix almost like magic. The harder you push it, the thicker and rounder it sounds, infusing gobs of analog saturation, density and smack in a pleasant and musical way. I don't think it's capable of sounding bad; it just sounds gorgeous every time.

AT THE ARMREST

In terms of sound, the EQ is nothing short of breathtaking, not to mention lethally powerful with those extended gain ranges for deeply sculpting the mids and achieving airy highs. Boosting the EQ favorably colors the signal with natural-sounding phase smearing, remaining smooth even under extremes; things never get too brittle or grainy sounding. Similarly, cutting doesn't have the harsh sound that many EQs do; instead, it's strangely smooth and doesn't leave behind a clinical emptiness. The LF subs don't quite reach the colon-busting 20 to 30 Hz range that the SL4000 desk gained fame for among hip-hop and remix producers, but the E and G EQ with peaking bell curves provide lots of options for letting low frequencies breathe and stand out by scooping out frequency interference. The highpass and lowpass filters have a gorgeous, smooth and transparent sound that doesn't display any annoying ring you often get around the cutoff peak of filters.

Aside from dutifully putting thwack into simple kicks and snares, the channel compressor seemed fuller, with more depth and punch when compared with the Waves emulation. And it could exude that classic throbbing sound from SSL consoles on more complex material such as piano and acoustic guitar. The sound of the fast-attack gate has been perfectly modeled, exhibiting that familiar zipper effect as the gate opens and closes when you turn up the gate high on sustained sounds.

DUDE, IT'S A DUENDE

With a price roughly twice that of the native Waves SSL 4000 Collection, some may find Duende hard to swallow, but you have to put the cost of processing power into perspective. Duende retails for about the same as the Waves TDM version, which runs roughly half as many instances on a card that costs more than double the Duende. To have the SSL plug-ins run consistently on DSP resources rather than consume a majority of your already-fluctuating CPU is well worth the investment. Then there's the fact that Duende sounds absolutely amazing, outperforming all the replicas with a cleaner, more aggressive and modern tonal character. Duende is also beneficial for mobile users to take the mixing strain off laptop systems and into a travel rack.

Take a moment to bow to Mr. Gabriel (yes, that would be Peter) for extending his company's previous professional-market-only paradigm to the more proliferous home and project studio markets. Now every room can truly be an SSL room.

For more on FireWire bandwidth and latency, read the review at remixmag.com.