Over the past few weeks I have been testing the new AVB range of interfaces from MOTU. Audio over Ethernet has been a pet subject of mine for some time, if this rapidly developing area of audio is unfamiliar to you then take a few minutes to read the 2 part primer on Audio over Cat 5 I wrote last year Part 1, Part 2. Of the various available technologies MOTU have implemented AVB in their latest range of interfaces. AVB stands for Audio Video Bridging and it is an open, non-proprietary extension of Ethernet which allows the distribution of audio across gigabit Ethernet with the proviso that all switches on the network meet a minimum spec and are classed as AVB compliant.

The AVB range from MOTU currently consists of:

1248 - 32x34 I/O with 4 mic preamps

8M - 24x26 I/O with 8 mic preamps

Monitor 8 - 24x16 I/O headphone amplifier/mixer

Ultralite AVB - Compact 18x18 I/O

16A - 32x32 I/O

24Ai - 24 inputs, 24Ao - 24 outputs

112D - 24/64 channel analogue/ADAT/MADI interface/converter

AVB Switch - 5 port AVB compliant gigabit Ethernet switch

Web Control And DSP 

To see the new AVB interfaces as just interfaces with a network port on the back would be missing the point. These interfaces all come equipped with a built in digital mixer, with flexible routing and DSP EQ, dynamics and reverb to complement the already comprehensive routing offered by the dedicated routing page in the web based UI. This is perhaps an easy to overlook aspect of these interfaces but all the control is via a web page served by the hardware itself and independent of any connected computer allowing standalone operation. It confronts my preconceptions but the computer is no longer the host in the system, its just another connected device on the network and the network can operate quite happily without a computer attached at all.

Several companies offer AVB compliant equipment, notably Avid with the S3L system. The possibilities for the complex distribution of audio across large sites using existing network infrastructure is reflected in some of the interfaces offered in the range, particularly the use of Phoenix Euroblock connectors on the 24Ai and 24Ao models. Even without the networking possibilities offered by AVB the new MOTU interfaces are very capable, modern, high quality audio interfaces in their own right but offering the potential for expansion by adding additional hardware to the network over time. To meaningfully evaluate the system, lets look at its constituent parts before building a larger system. Come back for part 2 where I'll be looking at the hardware in more detail.