Hydra2 provides seamless, scalable audio networking of audio mixing consoles with routers and I/O interfaces, allowing for a large numbers of inputs and outputs to be shared and controlled irrespective of location. Hydra2 does not compromise audio quality, performs with negligible latency and is founded on comprehensive, built-in fault detection and redundancy. Many of the world’s most successful broadcasters rely on Hydra2 infrastructure for live on-air application in both fixed and mobile installations every day.

At the heart of Hydra2 is the 8192² Calrec router (4096² on Summa and Artemis Light). Networks become more advanced when multiple routers are connected together to add additional mixing consoles, or to increase the amount of I/O connections available. Routers, mixing consoles and I/O can all be easily connected to the network as and when needed.

Hydra2 provides 1-to-n routing; input sources may be routed to any number of destinations in mixed formats, removing the need for external splits, distribution amplifiers and format convertors. Sources can be routed to multiple consoles, to multiple DSP inputs on each console and directly to output destinations all at the same time.

I/O units connect to a Hydra2 router via a single Cat5e or fibre link and can carry 512 channels of 24 bit 48KHz audio in each direction simultaneously, along with control and error detection data. Bandwidth between routers can be increased in multiples of 512 channels by adding additional Hydra2 links between them.

As with all Calrec products, audio quality and product reliability are our top concerns. All analogue pre-amps and line level paths are designed around our well proven and highly respected circuitry, providing very high headroom with a very low noise floor. Our lossless proprietary network transportation protocol does not compromise the high audio quality and maintains minimal latency.


H2O is a graphical user interface that provides administrator level control over Hydra2 networks and can be accessed via a web browser running on any PC with a network connection to the console.

By default, all mixing consoles on a Hydra2 network can access all the I/O on that network, irrespective of which router the I/O directly connects to. H2O provides comprehensive access rights management to the network, where users can manage the access rights of each individual console to safeguard set-ups and give privacy to multi-production environments.

H2O allows users to route input sources to output destinations without the use of a control surface, as well as edit I/O box labels, I/O port labels and port descriptions. H2O can also be used to enter SW-P-08 ID’s against I/O ports to allow control over source to destination routing by 3rd party controllers.

Hydra Patchbays

Unlike physical I/O interfaces, Hydra Patchbays are virtual patch-points within the Hydra2 domain that allows a console operator to patch DSP outputs to Hydra Patchbays, making them available to other console operators and H2O users on the network. Console operators can also use Hydra Patchbays as inputs, giving H2O users the ability to change the sources feeding input channels on control surfaces.

Hydra Patchbays are a powerful tool for control room and studio resource management, allowing remote network administrators to be able to put control rooms “on-air” and to manage the sources available to them.

Fixed Format I/O

Calrec provide a range of fixed format I/O boxes to provide the quantity and type of signal format required where it is needed. Each type of fixed format I/O box contains a set number of inputs and outputs, all of the same type/signal format.

The term ‘fixed format’ differentiates this type of I/O box from modular I/O boxes which can be custom populated with mixed signal formats in varying quantities.

Modular I/O

Modular I/O BOXES are 3U rackmount enclosures with 20 x I/O card slots that can be populated with a mixed range of I/O cards, allowing for a custom selection of I/O quantities and formats. Modular I/O boxes connect to a Hydra2 network in the same way as Fixed Format I/O.

Multiple I/O boxes can coexist on a Hydra2 network alongside fixed format I/O, if required, in order to make up the quantity of I/O in the format and location needed.


The Fieldbox is a portable I/O box which measures 220mm wide x 384mm deep x 40mm (<1U) high, It provides 8 x balanced analogue mic/line level inputs, and 8 x balanced analogue line level outputs, in a compact, cost-effective package. Threaded fixing holes in the base allow the unit to be secured in place if required.

The Fieldbox functions just like any other Hydra2 I/O box, providing remote control over input settings that utilise Hydra2’s sharing, protection and access management system, along with active status monitoring and a backup Hydra2 network connection.


The H2Hub provides a network distribution node that can be used to connect from a router up to 4 x external connections which may be I/O boxes or other Hubs to form a local array of I/O connectivity.

A single connection from any router can be switched via the H2Hub to multiple I/O units, and even another H2Hub if further I/O distribution is required – in fact 3 x H2Hubs can be daisy-chained together. The H2Hub’s connection and distribution options make it ideal for forming ad hoc networks, especially when combined with the Fieldboxes and other Calrec I/O infrastructure.


Br.IO is a 4U Hydra2 based external I/O Rack allowing for cost effective expansion of I/O for use with Brio and Summa consoles. This rack has the same complement of analogue and digital I/O that can be found in a Brio 36 system.

Br.IO is made up of 24 x Analogue Mic/Line I/Ps, 16 x Analogue Line O/Ps, 8 x Digital AES I/Ps, with SRC, 8 x Digital AES O/Ps.

For a complete overview of our range of Hydra2 equipment, visit our Resources page to download our Product Brochure, or for more detailed information login to download our Hydra2 Installation Guide.