A lot can happen in ten years. If you had been experimenting with the application of network technology in live audio systems back in 2007, you would have been a true pioneer - marketing people would call you an ‘early adopter’. Starting with 100Mb Ethernet technology protocols Cobranet and Ethersound, later introducing proprietary protocols Optocore and Rocknet, the live audio world quickly learned to make use of the exciting possibilities and functionality of network technology. Ten years later, the market adopted gigabit Ethernet networks as a standard - nowadays there’s hardly a professional audio mixer, stage rack or DSP processor that doesn't have an RJ45 connector to exchange audio with the world. Sound engineers learned to use network cables, program switches and design ad-hoc network structures to make their lives easier. This micro-tutorial presents the five most important topics in discussing audio networks.
Topic 1: Network or Point-To-Point ?
A network is an addressable content delivery system, as opposed to a point-to-point connection system such as AES3 (‘AES/EBU’), AES10 (‘MADI’), AES50 (‘Supermac’) which knows no addressing – it just delivers the audio to whatever is connected at the other end. Addressability has huge implications, allowing systems to be more flexible, more powerful and more scalable against lower costs per connection. So, if it’s clear that a system will never change and has a simple topology, a point-to-point solution is OK. But, in many cases, a networked solution will be more cost effective, while also making the system easy to expand, change and combine with other networked systems.
Topic 2: Audio quality and Sound quality.
All an audio network does is deliver audio from one place (address) to another - it doesn't change the audio itself in any way within the quality constraints (bit rate, sample rate, latency), so the sound quality (representation accuracy) is not affected. Sound quality - caused by actual changes applied to the audio signal - is influenced by a system’s analogue components (microphones, pre-amplifiers, power amplifiers and loudspeakers) and the algorithms running on the system’s DSP. The network protocol or hardware has no effect on quality. So, sound quality is an important topic to discuss when talking about the quality of audio systems, but the network is never an issue in this discussion.
Topic 3: Network protocols
If you find an RJ45 port on a professional audio device, it will most probably answer to one or more of the most commonly used gigabit Ethernet protocols: Dante, Ravenna, Q-lan or AVB. Sometimes the make of a certain product dictates the protocol because it only supports one. As it has the most manufacturers and products supporting it, today the most likely flavour to end up with is Dante. However, since all protocols are based on the same gigabit Ethernet technology, having implemented one protocol it’s still possible to connect to others (except AVB), through the use of the intermediate protocol AES67, or through routers that can support multiple protocols through interface cards. In that respect, life has become easier since 2007.
Topic 4: Redundancy
The reliability track record of networked systems has improved to nearly perfect in the past 10 years. But that doesn't mean an audio network cannot fail - cables can break or switches can crash. It’s good to know that many Gigabit network protocols offer redundancy options - either in the protocol itself, or by making use of the many standard redundancy options in Ethernet switches. Applying redundancy usually only means using the double amount of Ethernet switches and cables. This means that redundancy can be designed into systems at relatively low cost - it's up to you.
Topic 5: What else ?
If a network is used only for audio then it’s easy: connect, patch and enjoy. But an Ethernet network can be used for many other creative things: video; PC, smartphone and iPad mix control; wireless system controllers; multitrack recording (without needing any interface) and so forth - anything that works on an Ethernet network also works on an Ethernet based audio network. It just needs very careful planning: for example a common problem in audio networks is someone adding a wireless access point (WAP) without disabling its DHCP function. So, when creativity sets in, make sure there’s an engineer with some IT experience nearby to support it.
To summarise: Today’s networks offer the sort of functionality and scalability that we could never have dreamed of ten years ago, at a lower cost compared to analogue and digital multi-cabling.
If you would like to dig deeper into the topic of audio networking, check out the further reading materials below or attend one of our YCATS Yamaha Commercial Audio Seminars. You can find the European schedule on www.yamahaproaudio.com/training
Next week’s micro tutorial will focus in on something analogue: ‘amplifier meets speaker: how to select the right amplifier’.
Introduction to Networked Audio
Dante network design guide