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SSL Duende DSP Accelerated Plug-ins

Audio engineers all over the globe, and of all stripes, took notice when SSL introduced Duende about a year ago, because now anyone could buy 32 mono channels of SSL EQ and compression for around $1,500 street.

Solid State Logic has been a standard in high-end professional audio production for decades. Smaller studios and home recording enthusiasts have long viewed SSL gear as an idyllic, yet non-realistic dream, and to incorporate their signature sounds into a production (unless a budget allowed for recording in a pro studio) was unrealistic, even while many rack-mount SSL modules became available during the last half-decade. Shelling out a few grand for any SSL signal path (or partial path) was, and is, still out of budgetary reach for many.

So, audio engineers all over the globe, and of all stripes, took notice when SSL introduced Duende about a year ago, because now anyone could buy 32 mono channels of SSL EQ and compression for around $1,500 street. Originally introduced for the Macintosh PPC DAW market, Duende was later made available for PC and MacTel systems with the release of new drivers several months later.

Many users experienced compatibility problems and headaches with the early drivers. SSL worked hard to quickly handle these problems by establishing a dedicated section of its website ( for FAQs detailing common usage issues and solutions.

It was my assessment that since this was SSL’s first venture into releasing its own end-user processing software, they should be extended some grace as they worked out the issues and released driver updates. Still, many frustrated users who shelled out their hard earned cash were rightfully a little reluctant to wait through the headaches.

Now, one year and multiple driver revisions later, it seems appropriate to revisit the Duende to check what progress has been made, and how viable it is for a user to consider this widely desired device.

Fast FactsApplications
Studio, project studio

Key Features
32 channels of SSL C, E and G Series EQ and dynamics up to 96 kHz operation; standard VST interface; RTAS and AU drivers for Mac; 1RU hardware; Duende Control Panel software; two FireWire 400 ports


Solid State Logic | 212-315-1111 |


  • 32 channels of true SSL dynamics
  • Easy installation and interface
  • Sounds amazing


  • Compatibility
  • Cannot manually type in values
  • Requires dedicated FireWire buss

Duende’s 32 channels of SSL EQ and dynamics make it a remarkable performer, but beware of potential system compatibility issues.Features

The Duende hardware is a sleek, simple 1RU device with a very basic layout. It is lightweight, only four pounds, which is favorable for mobile use. On the front panel is a power button which glows with a blue rim when on. The rear of the unit consists of a power jack for the auto-adjusting power supply and two IEEE 1394 (400 Mbps) FireWire ports. The power supply is shipped with a number of international plug adaptors for use with the wall wart-type power supply. The unit can also be powered via the FireWire buss, providing the host computer has a 6-pin FireWire port and can handle such powered devices.

The Duende is not new code aimed at modeling SSL gear, but proven technology taken directly from the popular C series consoles, which were originally modeled from the 9000K, and E and G Series EQ.

The Duende Control Panel is the software for monitoring the unit’s DSP usage, and is lightweight and basic with no user input required. It shows the four banks of processors built to handle eight mono or four stereo channels each for a total of 32 channels at 44.1, 48, 88.2 or 96 kHz along with the Driver and Firmware version and the serial number of the unit. VST is the chosen interface standard for the Duende. Most audio applications that support VST will work with Duende, and SSL has a list of compatible applications listed on the company’s website. RTAS and AU drivers for the Mac are supported via an integrated VST-RTAS custom wrapper developed by FXPansion.

In Use

This is clearly one of the best DAW EQ and dynamic processing options on the market. As expected, the EQs are very smooth and easy on the ears; although this applies to all bands of EQ, I was particularly pleased with the upper frequency filters. Dialing in the perfect mix of presence and air is a cinch with the Duende.

The compressor performance was flawless: whether using it for minimal dynamics or really spanking the signal, the SSL lived up to full expectations. I quickly fell in love (again) with the SSL Stereo Buss compressor. It is simple enough for people not familiar with this particular compressor and it is like an old friend to those of us who have used it for years.

Many people have asked about the Duende compared to the popular Waves SSL plug-in bundle, and I had a chance to compare the two side-by-side. Although they are modeled after different SSL EQ styles, the Duende is clearly a smoother overall dynamic processor. The Waves is good for what it does, but the Duende, to my ears, is just better.

The Duende software is pretty straightforward. Color and layout is similar to an SSL 9000K channel module although more compact and includes standard routing options including where the filter is located in the chain and the ability to side chain. At the bottom of the display is a graphical layout of the signal path. The V2.0 driver provided mouse wheel control of the knobs. Users can Shift-click to fine-tune the knobs. A simple CTRL click (PC) or COMMAND click (Mac) resets the knob’s position back to default. The plug-in is missing the ability to double click and manually type in a numeric value. This is a feature I have been accustomed to having on other plug-ins, as I have found that it is sometimes easier to get the parameter to my desired setting without having to “turn” the knob. Duende also supports the ability to “freeze” tracks in Nuendo and Cubase, which frees up the DSP on the Duende. There is no graphical representation of the frequency plot when adjusting EQ; this is not critical, but has become a common feature for EQ plug-ins, and could be missed by users … especially those not familiar with the general performance characteristics of SSL.

No one will be disappointed with a Duende investment, except for when he or she encounters the aforementioned compatibility problems, and here is where the real Duende adventure began for me. I will reference some of my own experiences, as well as feedback from a few other engineers who have been active with the Duende since before the latest drivers have been released.

The first thing that someone considering a Duende purchase should note is the unit likes to have FireWire bandwidth all to itself. Problems are almost guaranteed when sharing the FireWire buss with any other device. This does not mean a separate port on the computer; it means a completely separate buss. Most motherboard-based FireWire ports use the same buss, so to successfully use the Duende when other devices are connected and in use a PCI FireWire card purchase is a must. (SSL lists compatible cards on the Duende support webpage). Potential purchasers should take this into account, because the limited number of PCI slots available on newer computers can be used up quickly (and laptops offer another set of challenges). With the late August v2.1 driver release, up to two Duende units can now be daisy-chained, providing 64 mono plug-ins at 44.1/48 kHz and 32 mono plug-ins at 88.2/96 kHz.

The Duende can also offer performance problems when interfacing with other VST/RTAS/AU plug-ins. I experienced this first hand when testing the first generation of drivers in January with a system owned by engineer David Terry of Nashville. He was running Nuendo 3.x with three UAD PCI cards and Lynx AES 16 audio cards on a professionally built custom audio PC. The Duende worked great at first try, but once we put one of the UAD plug-ins on a channel any other channel with the Duende in use was immediately muted. SSL’s work-around for this was trying to reorder the UAD PCI cards, but since this was not my system I did not feel comfortable cracking open the case and swapping around his PCI cards.

Early Reports on Driver 2.1Since I completed the review of Duende using driver 2.0, SSL has released 2.1 and the reports have been positive. New features include linking two units together (at 44.1/48 kHz it is recommended that each unit is on its own FireWire buss; for 96 kHz, this is required).

I still must use stereo plug-ins when inserting on a channel in SONAR 6.x, as mono is not compatible and produces a ghosting effect. In this instance, this essentially cuts the capability in half. In the original Nuendo test, Duende worked well yet did require periodic reboots throughout a week-long mix session. Unfortunately, I have not had the opportunity to validate if this is better with the new drivers.

It should also be noted that LaCie drives do not play well with Duende, regardless of the FireWire buss, due to the FireWire chipsets used. As for audio interface compatibility, there have not been any major changes. However, SSL is working with many different manufacturers to work out compatibility issues, and the company updates the FAQ section of its site with any changes.

I still recommend trying the Duende on your system to verify compatibility before committing to purchase, although the new drivers do give reason to be cautiously optimistic.

—Dan Wothke

The manufacturer responds:
“We have put a lot of work into the new V2.1 software, both internally and working with third parties such as Apple to streamline the efficiency of new software. Reports from users are very favourable. We learned a great deal about FireWire, Macs and PCI busses in this development process. This information has been added to our web FAQs to help better support our user base for the future.”

—Niall Feldman, SSL Director of Product ManagementWith the Duende being lightweight, physically,, it struck me that this would be a great piece to carry and use on different systems. However, after this problem I was cautious of this option. Once the 2.0 drivers were available I went back to David to try it on his system. He had since upgraded his DAW and put all of his PCI cards in an expansion chassis. At first, the Duende worked flawlessly on his system, although I’m not sure if that can be accredited to the moving of the PCI cards, the new system itself, the Duende driver, or a combination of the three (I would gamble to say it was the latter). After a couple days of use, David experienced the mute bug when having a combination of native VSTs, UAD and the Duende inserted on the stereo buss. After a series of reboots did not restore the audio path, the problem was finally resolved by clearing the stereo buss and reinserting some of the plug-ins. Although we never confirmed exactly what had caused the problem, it was isolated to the Duende; whenever the Duende was removed from the buss, the audio passed through. When the Duende worked well, David found a new go-to EQ and track compressor and was reluctant to give it back to me for further testing.

On my home system — IBM Netfinity Server, VIA OHCI Compliant FireWire card, SONAR 6.0, Aardvark Q10 — everything was going great, even though none of my hardware was listed as compatible. The install was fine, SONAR didn’t hesitate to recognize the Duende, and I was off to mixing.

Then I tried bouncing to disk. When listening back I noticed pops and clicks from the mix. I did some additional testing with Acid 6.0, which also played nice with the Duende, but had the same results when mixing down using the Render option. Any track with the Duende experienced the pops and clicks, including the stereo buss. After troubleshooting with the SSL team via the web interface, I determined that it was due to the Duende and the bandwidth needed when not bouncing in real time. When I bounced in real time, the pops and clicks were gone. The problem also occurred with David’s latest setup and the Duende 2.0 drivers using Nuendo’s offline bounce feature. Using the Real Time bounce option, the pops and clicks were non-existent.

I spoke with Chuck Zwicky, engineer from New York, who is a Duende user with an Apple system running Logic 7.2.3. Chuck reported early problems with dropouts and timing issues, but suspected the problem was with the Apple FireWire driver. After running the update from Apple, everything has behaved quite nicely. Chuck also noted the quality of the Duende sound. In his exact terms, “the Duende EQ is the only digital EQ I have used that does not cause ear fatigue.”


I felt it was important to document some of the more common troubles associated with the Duende, but I should note that there are many users who haven’t experienced any complications .There are also those who could never resolve their problems and ended up parting ways with the Duende. My experience with SSL via the web support portal was favorable; the company showed its desire to work with users to get problems resolved, though some of the problems seem to be across the board, regardless of platform or host applications.

Here’s the bottom line: You won’t find a better DAW EQ and dynamic processing investment than the Duende, providing that it plays well with the rest of your setup. Thirty-two channels of vintage SSL in a single-space rack unit makes my ears smile, and, if it plays well with your system, you will be smiling, too. However, I strongly recommend a careful look at the latest online Duende support documentation and, if possible, a test drive with the Duende on your own system.

SSL Duende Drumstrip

The first add-on for the Duende is the SSL Drumstrip. The Drumstrip consists of five new and enhanced audio processing tools specifically for drums, both acoustic and electronic. These include a gate with a wide range of controls, a transient shaper, HF & LF enhancer, and a Listen mic compressor. The sections are bookended by Input — which includes metering and gain — and an Output section — with gain, metering and a Mix knob to control the overall amount of Dry vs. Wet applied to the signal.

The look of the Drumstrip is very sleek and modern. Each virtual knob changes color to represent the amount of processing for that particular parameter. The five different sections each have their own Power button to activate the section.

First, I ran the Drumstrip through the gamut with a full acoustic kit. It was very easy to dial in exactly what I wanted using the Gate. The controls were easy to navigate, and, just as importantly, the visual layout of the Gate was well thought out. There are different colored indicators on the Gate meter corresponding to Open, Close and Range parameters. Visually, this gate is a breeze to work and works well.

The transient shaper offers a way to grab the attack of a drum, adjust the characteristics of the attack and blend it back into the original signal. It is controlled by the input Gain, Amount and Speed. Audition quickly became my friend, as it acts similar to that of a side chain listen on a compressor; I could hear exactly what I was tweaking. Inverting the signal is also available, and is a great help when working to get the phase of a drum or combination in drums correct. Snare and toms were primarily used during my run. With the audition button, I could grab exactly what was needed and then mix it into the signal.

HF and LF enhancers, not the same as EQs, work on the premise of dialing in 2nd and 3rd harmonics to the signal respective to the enhancer in use. Freq, Drive and Amount are the only controls for the enhancers, and, again, it was really simple to begin adjustments and discover the true potential of the drums. This is one of those plug-ins that I just start turning knobs to find what I like. I used the LF to round out the punch of a snare drum and it did wonders with the kick, really giving the extra bottom that was needed.

Here, the popular Listen Mic Compressor is modified for more control. Improvements include the ability to bypass the original hard high and low filtering, which allows the compressor to apply full bandwidth processing. I applied this to the mono overhead room mic, and for this particular application a little of this compression went a long way, although squashing the signal resulted in some creative results.

I found the Drumstrip to be a great tool for digging into drum sounds, naturally pulling out characteristics of the drum without adding unnecessary artifacts or over-hyped frequencies to the overall sound. SSL obviously put a lot of thought into the Drumstrip, and I was very appreciative as I did not even have to think when using these plug-ins; I just started working with the interface and enjoyed the results.

The Drumstrip is available as a free 30-day trial included in the new Duende V2.0 driver.

—Dan Wothke