Change in the intercom systems market marches on. The transition from analog to digital party-line systems continues, with multiple communications channels possible on a single microphone or data cable – though traditional analog intercoms are still widely used for less complex productions.
Highlighting this transition, a Clear-Com digital two-channel HelixNet intercom speaker station shared space with an old-school call-signal flasher on the front of house console at the most recent Monterey Jazz Festival (pictured above/left).
Supporting the trend toward digital intercom, several manufacturers have incorporated Internet Protocol (IP) into their systems. IP technologies are used to interface systems at different locations together, to communicate between central intercom frames or servers and remote multi-channel intercom stations,and to bring smart phones and similar devices into the communications loop via 3G/4G cellular networks and broadband connections.
Shawn Anderson, intercom product manager for RTS, notes, “The biggest trend in the past 18 months is the migration to an IP backbone, with many customers requesting quotes for these types of products.”
The quality of voice communications, and of any program audio sent with the intercom, has improved markedly with the advanced audio codecs now built into systems. Wider frequency response with greater intelligibility, higher signal-to-noise, and better echo cancellation are all found in newer intercoms.
For example, the Riedel Performer digital intercom has a frequency response of 20 Hz to 12 kHz (+/-3 dB) at both the beltpack and base station headphone amplifiers. Clear-Com I.V.Core technology offers low-latency, wide-bandwidth audio over IP, and works well over Audinate Dante and AVB digital audio networks.
The latest RTS digital matrix intercoms have proprietary OMNEO technology that uses Dante for a supported bandwidth of 100 Hz to 20 kHz within the intercom frames and panels.
Digital Party-Line
The Riedel Performer offers two- and four-channel master stations, two-channel beltpacks, and desktop speaker stations – all connected via AES/EBU 110-ohm twisted-pair XLR cables. The maximum recommended distance between connected beltpacks is 300 meters (just under 1,000 feet) and the entire party-line can contain over a mile and a half of cable.
The beltpacks can be daisy-chained or have direct runs via a proprietary splitter. This system was the first commercially available digital intercom and has been around for about a decade. Clear-Com’s digital party-line offering is HelixNet, a four-channel system consisting of base stations, two-channel beltpacks, and speaker stations using I.V.Core audio and IP technologies.
Debuting about five years ago, the design utilizes existing intercom cable infrastructure and applies it to digital communication. The four independent, full-duplex channels use a single twisted-pair connection, such as standard mic cable or Cat-5/6 data cable. The beltpacks and speaker stations can select from any of the available channels, and change the selection as desired.
Each 1RU base station can support up to 20 connected beltpacks or speaker stations. Interface modules allow seamless connections with two- and four-wire audio devices, including analog and digital matrix intercom systems and telephone circuits. Ethernet and fiber interfaces connect up to three HelixNet base stations together, for a 12-channel system that operates over a single twisted-pair.
