DETROIT – On Stage Audio (OSA) participated in the first application of the IEEE 802.1 AVB Bridging protocol using HiQnet-enabled Harman gear for the Compuware national sales meeting at the Masonic Theater here recently.
Harman noted that this was the first time that AVB – a standard transport protocol that allows time-synchronized, super-low-latency streaming audio and video over IEEE 802 Ethernet networks – was used as the primary audio transport for a major event.
OSA's crew, led by Jim Risgin, vice president, used HiQnet-enabled Crown Audio CTs Series amplifiers with USP4AVB cards, dbx SC 32 Digital Matrix Processor, BSS Audio / NETGEAR AVB bridges, and HiQnet System Architect and ran audio using Ethernet AVB standards for the event's 1,500 attendees.
Harman, which chairs and edits the IEEE P1722 Committee and edits the IEEE P802.1Qat Committee, supports the development of AVB switching and product technology through its Harman Corporate Technology Group and System Development and Integration Group (SDIG). The company is also a member in the AVnu Alliance; the industry forum dedicated to promoting the adoption of the IEEE 802.1 AVB and related IEEE 1722 and IEEE 1733 standards over various networking link-layers.
Risgin's design used 24 Crown CTs 3000 power amplifiers fitted with USP4/AVB cards, four 24-port BSS Audio / NETGEAR AVB bridges and four dbx SC 32 Digital Matrix Processors – the AVB "on ramps" for the system processing. Harman's HiQnet protocol and System Architect software controlled the entire system (DSP and AVB).
Risgin, an active supporter of AVB, assembled the Compuware AVB system working closely with SDIG. He used HiQnet System Architect's drag-and-drop design interface to design his system, configured and programmed the dbx SC 32 Digital Matrix Processor for processing, and used the AVB network as the matrix automatically instructed groups of Ethernet AVB amplifier channels associated with each physical zone to switch to that networked audio signal.
The dbx SC 32s, used as the "on ramps," converted the incoming analog audio to digital AVB streams. Fourteen audio streams were then routed via HiQnet System Architect to the 24 Crown CTs amplifiers with Crown USP4 DSP-based PIP (Programmable Input Processor) input modules connecting the amplifiers to the Ethernet network. This enabled real-time transport of digital audio via Ethernet AVB and also allowed the CTs amplifiers to be remotely controlled and monitored via HiQnet System Architect.
"The systems performed flawlessly," said Risgin, who notes that AVB-induced latency was less than 500 microseconds for all devices, and that delay from input to output maintained the <2ms specified by the AVB protocol. He credited Harman for "making a complex process far more simple. Everything on the network was completely transparent," he added. "Troubleshooting was simple because we were able to verify that all the signal paths were correct, and there was instant metering available as soon as an AVB stream was connected to the network. The Crown amplifiers' load-monitoring capability verified that each speaker was working and with the correct loading, and the drag-and-drop audio routing really streamlined our workflow process."
Comparing his AVB experience with traditional system design and routing, Risgin identified AVB protocol benefits. "We would have been working with either analog audio signals on twisted-pair copper cabling, with the potential for failure increasing as the number of signal paths increased or other IP based transport solutions that would increase the complexity immensely" he said. "With analog we'd have had to deal with interference, hum, and noise rejection issues while other IP solutions would have required an IT technician- in short, we'd have been working in a different age. Even with the existing networked audio protocols, AVB improved the simplicity of coordinating the system and organization of the components. Ethernet AVB has changed everything – for the better."
Echoing Risgin's comments, Adam Holladay, market manager for SDIG, noted, "Where HiQnet simplifies and enables complex programming, monitoring and control, AVB simplifies and enables complex multichannel audio and video transport. The elegance and performance of the HiQnet and System Architect pairing is matched only by the comprehensive integration that is provided by AVB networking. The commitment of the AVnu Alliance to advance AVB as the universal standard for audio and video transport – indicated by the ever-increasing company membership – really shows that we truly can expect significant industry-wide benefits to many members of the professional A/V community in the not-too-distant future."
HiQnet was developed by engineers from across Harman's Professional Division and is coordinated by Harman's System Development and Integration Group (SDIG).
For more information, please visit www.harman.com and www.osacorp.com.
