SD7: The next generation plus one of digital sound engineering.

Stealth Processing

Powering the SD7 is our latest in high density digital processing, the all-new Stealth mixing and routing engine, exclusive to DiGiCo.

Based on the latest incarnation of FPGA (Field Programmable Gate Array) technology, known as Super FPGA, it’s a core component of the SD7’s quantum leap in console design.

Allied to three of the latest generation of SHARC® effects and control processors, it endows the console with a staggering eight times the overall processing power of a D5 Live.

The benefits are to be found not only in the high resolution audio processing that makes 128 simultaneous 192kHz signal paths readily achievable, or 256 at 48kHz/96kHz, but limitless flexibility too.

Make the most of 448 simultaneous optical and 224 MADI and 24 analogue and AES/EBU connections, plus 128 busses, 32 matrix busses and 32 graphic equalisers, to build the biggest and most complex shows.

While two new-generation Tiger SHARC® chips (each representing the power of almost a whole D5) provide an awesome array of quality reverbs and effects.

And in packing all this power into just four chips against the
D Series’ 39, the SD7’s efficiency is dramatically increased, while space has been freed up to allow two complete redundant processing engines to be accommodated within the console.

Best of Both Worlds

Some consoles remind you of their analogue roots. Only DiGiCo lets you forget them

While some sound engineers have embraced wholly different working techniques in the digital era, if you’re already a DiGiCo user the chances are you appreciate the logical thought processes that accompany working in the analogue idiom.

However you think, though, intuitive operation is as crucial to responsive live mixing as ever, and throughout the D Series’ design it’s a core philosophy that your next task should always be instantly accessible.

The massively increased processing power of the SD7 means we’ve been able to take this concept much further. Retaining the instant accessibility of its predecessors while adding new flexibility and sonic purity.

Routing options are more extensive than ever, while the generous provision of 32 units of graphical equalisation is more powerful still. And no analogue console has ever allowed you to instantly place input and output channels side by side.

The way these functions and more can be accessed, tweaked, stored and instantly recalled is pure digital control at its finest.

The best of both worlds. So intuitive you almost forget it’s there.

Inituative Operation

If the word 'intuitive' seemed to have been invented for DiGiCo's D Series, for the SD7 our designers have exploited the intervening five years’ technological developments to deliver an even more richly rewarding user experience.

You can choose to configure your SD7 for front of house, monitors, theatre or live to air, or use it as an interactive part of a multi-console system (it’s fully compatible with any DiGiCo or Soundtracs console).

Either way you’ll see your complete signal flow laid out with unprecedented clarity, throughout each of the 256 processing paths that link the 448 optical, 224 MADI, and 24 integrated I/Os.

The stunning backlit polycarbonate work surface with its HTL (Hidden Till Lit) indicators is both a vision of clarity in any ambient light, and a paragon of durability.

With unique, innovative touches like built-in VNL video monitoring, interactive dynamic metering and a design that will give you full dynamic equalisation on any single path simultaneously, never has so much power to design, create, fine-tune, mix and operate a show been so literally at your fingertips.

Touch Screen Heaven

Touch screens have always been part of the DiGiCo work surface experience. On the SD7, as you’d expect, they’ve leapt ahead of current standards.

Our desire to provide larger screens than the standard 10.4inch met our wish to provide faders in larger sections. So each of the three new 15 inch TFT LCD touch sensitive displays sits above a group of 12 faders for clearer, more logical operation.

In common with every other key area of the consoles display, the metering’s light level is individually adjustable to suit everything from a festival mix tower to a Broadway theatre.

All of the D Series’ intuitive touches such as electronic scribble strips and labellable buttons are also here, now greatly enhanced by new full-colour backlit control knob digital collars and the high contrast afforded by the SD7’s black polycarbonate control surface.

Besides carrying all its labelling on the back, giving the ultimate in surface durability, it conceals numerous LED indicators that appear only as and when required to maximise visual clarity and minimise clutter.

Inspired by the marine industry, these ‘Hidden Till Lit’ (HTL) context-sensitive indicators appear just when they’re needed.

Another pro audio world first from DiGiCo.

FOH

If we were asked to state the DiGiCo design philosophy in one line, it would have to be that the mix comes first. The SD7, like the D Series, was created not as an example of how to use digital technology to feature-pack the smallest possible mixer, but as a professional sound engineer’s tool that would let you mix a live show – from the smallest to the largest – in a truly live way. With instantly identifiable settings, signal indicators, physical, grabbable controls and tactile, responsive touch screens.

From the high resolution, context sensitive meterbridge and giant 15 inch LCD displays to the touch sensitive motorised faders and colour-coded electronic scribble strips, you always know exactly where you are. All the essentials (and far more) for high end front of house engineering are here, with seemingly limitlessly flexible but always accessible routing, dynamics processing, grouping, muting, matrixing and metering.

When you move from rehearsal to first night, or from Europe to America, your entire show’s settings stay with you for instant recall from your USB key. And when it comes to recording the show itself, the ‘copy optical to MADI’ function lets you simply plug in your 160 track HD system and go. Something to make the record company appreciate you even more.

Dream Monitoring

Just because it's said to be the toughest job in rock and roll doesn't mean it shouldn't be a pleasure. While you’re suffering the slings and arrows of outraged lead vocalists, at least you’ll know that with the SD7 your console has been designed specifically for you.

The attention to detail begins with the monitor spec and thus, perhaps with the rider. If you’re mixing on Brand A wedges one day and Brand B the next, why not set up your aux send EQs on a memory scene for each type and simply press a button to call up one or the other?

Equally invaluable will be the 32 x 32-band graphic equalisers (all recallable, of course, and with centre-detented faders). They’re in addition to the channel EQ that can either be 4 band parametric or 4 band dynamic EQ at the touch of a button.

128 busses with full processing, and the ability to assign a channel or buss to either or both of two solo busses, allow you to set up previously impossible monitor mix situations. Yet the SD7’s colour coordinated halo rings, scribble strips, screens and modules give you instant recognition of operation modes. However you’re working, with DiGiCo VNL (Video Network Link) you can even mix the band when they’re not in direct view. And VNL, the world’s smartest shout system, keeps you in visual and text touch with both front of house and broadcast.

Theatre Mixing

The SD7’s powerful and refined hardware and Stealth engine are ready for the toughest demands of theatre audio, and with the optional SD7T (Theatre) software kit the console’s functionality and work surface are instantly reconfigured to make the most of it.

Start your session with SD7T software and a wealth of specialist theatre audio tools are right at your fingertips, providing an immensely versatile palette of tools for sound design, rehearsal and show operation. The SD7’s key generic benefits – including its awesome Stealth processing power and dedicated SHARC®-based effects and dynamics processing, 32x32 output matrix and 5.1 surround controls – are of course at your disposal, as are the instantly reconfigurable 12-input channel sections and 15 inch TFT screens.

Specialist theatre audio features include Live Update (to automatcally save all occurences of changes to the same source within multiple snapshots); comprehensive Cue and Scope that can now be selected by individual channel; cross-fade by channel or parameter; and Parameter Recall safe for individual channels and outputs.

Individual user defined crossfade times between parameters make for precise dynamic scene programming and a 32 x 32 Matrix (with nodal delay incorporated) allows for accurate time allignement, while the 12 VCA Master section is designed with wide fader spacing, ideal for theatre mixing.

FPGAs in Audio Mixing

Developed in the mid 1980s, the FPGA or field-programmable gate array is a semiconductor device that can be configured by the user after fabrication, unlike a DSP chip, for example, which once manufactured is essentially fixed. It would be wrong, however, to assume that FPGA’s are only suitable for routing and other simple functions as today’s FPGA chips are far more sophisticated than those early devices and can be programmed to carry out extremely complex operations at high clock speeds. It may be more appropriate to think of the FPGA as the equivalent of a reconfigurable ASIC or Application Specific Integrated Circuit as its very programmability enables it to be tailored exactly to the designer’s needs. By contrast, a DSP chip or computer CPU chip is designed to be useful in as many applications as possible, which means it needs to be a general purpose device and therefore not as ‘streamlined’ in its operation as a chip with a dedicated single purpose. You could think of it as the difference between a program written in machine code and one compiled from a high level programming language; a well written machine code program will always run faster than its compiled equivalent.

FPGAs are programmed using the logic equivalent of a circuit diagram and therefore can be made to carry out any task that an ASIC can, the advantages being that the chip’s ‘circuit diagram' can be updated at a later date without the need to replace components or even to open the case. There are also no fabrication setup costs, and because the devices are produced in large quantities, there is less likelihood of a parts supply bottleneck as might occur when using ASICs which need to be ordered in batches and well in advance. Earlier FPGAs were less efficient and slower than ASICs but today the difference is much less significant and in the area of audio mixing, FPGAs have some distinct advantages.

FPGAs comprise a series of logic blocks plus a system for connecting them. These logic blocks can be programmed to perform complex operations or more routine tasks normally associated with basic gates, and in many high performance FPGAs, these logic blocks also have access to on-chip memory or even embedded microprocessors. For the manufacturer, one clear advantage over the ASIC is that there is no expensive refabrication if the design needs to be revised. FPGAs are also ideal for relatively low volume applications as the development costs required to design an ASIC make the unit cost very high.

Applications for FPGAs are very wide reaching, as you’d expect from a device that is freely programmable, and this brings about certain economies of scale, but they are particularly well-suited to audio mixing applications, not least because a single FPGA can carry out the same functions as a whole board full of conventional DSP chips. Because an FPGA can be configured with many parallel signal paths, its is possible to achieve the necessary computational density at lower clock rates — exactly the scenario that prevails in a mixer where many parallel audio streams need to be processed and then combined.

While there is undoubtedly a manufacturing convenience aspect to using FPGAs in digital audio mixers, which in the grand scheme of things are low production volume items, they have some additional technical advantages. By programming them to perform a dedicated  tasks such as mixing, which includes the necessary EQ and dynamic processing, the time between audio entering the mixer and emerging at the outputs (latency) can be kept to an absolute minimum. Furthermore, tackling the problem using multiple DSPs requires very close attention to clocking to keep all the separate parts of the system in sync. Every audio engineers knows the importance of a stable, very low jitter clock and the subsequent audio quality benefits, but in digital systems there are many complex clocking issues that aren’t directly related to the audio conversion process, and where the processing load is spread over multiple devices, these problems become more difficult to resolve.

By contrast, a single high capacity FPGA can be configured as a complete ‘mix engine’ on a chip with exactly the right amount of floating point mathematical resolution to accommodate the functions being asked of it. This ‘mix engine’ runs from a single clock input where its floating point architecture provides a huge amount of internal headroom and is more resilient to rounding errors, and the subsequent distortion that ensues, than a typical fixed point system.

Summary
While there are many ways to accomplish digital mixing, the FPGA offers economies for the manufacturer while allowing the design to be optimised to meet the specific requirements of multichannel mixing, including the capacity to support EQ and sophisticated dynamic processing on all channels and busses. This in turn passes on benefits to the customer, not only in cost but also in audio quality, very low latency, overall capability and the ability to easily update the FPGA ‘mix engine’ at a future date should this be required.

Perhaps the main reason that FPGAs are not more prevalent in this area of audio technology is that there are many engineers who already possess the necessary skills to program PCs and DSP chips but relatively few who are skilled in both FPGA programming and the rather specific requirements of audio mixing consoles. Given these factors, for most companies a product can be taken from development to market more quickly if it uses established DSP technology, though this trend may eventually be reversed as the companies offering FPGA’s are now promoting their products throughout universities and colleges, sometimes offering subsidised development systems to encourage more students to study them in depth. Those companies currently using FPGA’s effectively in complex audio products such as mixing consoles are only able to do so because they realised their potential many years ago and made a conscious decision to gain the necessary expertise.