Based around the Stealth FPGA technology that delivers the SD range's acclaimed sonic quality, the DiGiCo SD Rack is the first I/O rack for any mixing console that offers multiple format sample rate conversion and allows up to an amazing 448 I/O, in any combination at 96kHz, spread across multiple racks.
While the SD Rack converters can operate at 192kHz, you can also select other sample rate options for specific outputs – for example, MADI at 48kHz for broadcast or recording feeds, or 96kHz - meaning that the SD Rack serves as a multi-sample rate signal splitter, which even allows you to use DiGiCo's next generation ultra-smooth microphone preamps to replace the standard microphone preamps of an analogue or other brand of digital console.
The system delay is minimal with DiGiCo setting the benchmark again. At 96kHz, the measured delay from the stage rack A-D, through a full channel with processing via the bussing with processing, back to the stage rack D-A is around 1mS. Also integrated with the MADI split is Gain Tracking™, which allows another console or a broadcaster to take any of an SD Rack's AES, analogue or MADI outputs at a stable level, irrespective of the microphone preamp settings on the SD7, covering a signal level range of +/-40dB.
This can be turned on at any time, so the one pre amp for each physical input can have four independently controlled levels. The SD Rack has a 56 input / 56 output arrangement, in blocks of eight, and can accommodate multiple digital formats, including:
•Analogue mic line inputs and outputs
•AES inputs and outputs, both with sample rate conversion
•AES I/O card •Aviom - second generation module
•ADAT module providing eight ins and outs
•AES 42 module
All card formats are independently hot-swappable and auto-detecting using Micro Blaze technology. The Mic card user feedback is provided by multiple LEDs and any input can be split internally to any opposing output on the rack. Power supplies are also hot-swappable, with the additional feature that all main connections are at the top of the rack, making for exceptionally easy access.
Finally, there is a full RGB backlit display that can also be used to control and programme the unit.