The Artist digital intercom network from Riedel can accommodate any audio format and scales from 8x8 to 1024x1024 non-blocking ports, as well as provide native support for IP and the company's Bolero wireless system.
First off, any discussion of intercoms for production would be remiss without first defining common terms. Skim these, and if you're familiar with them all, read on for more specifics.
Glossary of terms
Simplex - One person at a time transmits, everyone else listens. If you are transmitting, you cannot be listening.
Duplex - Simultaneous two-way communication, multiple people can talk and listen at once.
Matrix - Point-to-point, private line, or create groups by programming cross points.
IFB - Interruptable Fold Back, which allows someone to hear a program feed and director's communication. Good examples include sports commentary, where the talent can hear the program feed and producer directions, as well as themselves; or an on-location reporter who can listen to the anchor in the studio and the director in the production suite.
Party line - All users are in the same conversation, typically full duplex, non-private.
Channel or Bus - Some systems allow for grouping based on channel or bus selection. An example is if you have FOH, Lighting, and Video all on the same intercom, FOH can be on channel A with Lighting and Video on channel B. Those conversations will not compete or connect to each-other. Some systems allow for those conversations to be linked in or out quickly. Also known as tiered work flow.
Two wire - In a communications system where both talk and listen are on the same path. In electrical pathways there are, in fact, two wires (one path).
Sidetone - Small amount of microphone fed back to earphone so they speaker can hear him/herself. Typically it’s good for confirming you don’t have your microphone muted.
Call Button - A button on many systems which illuminates a light on all the other body packs and base stations on that channel. Essentially it is an attention-getting device, great for letting people who removed their headset know to put them back on. Many systems will have an optional integrated Klaxon that can provide both a visual and auditory alert.
PTT- Push to talk
Hands-free - The ability to talk and listen without pushing a button or key
Point-to-Point - Essentially a private line from one operator to another.
Work flow - The understanding of how an event or show is run. The most important part of intercom system planning.
Panel or station - A piece of hardware where a person can access a communications path with an intercom system.
Power supply - That device by which the intercom system is powered. Some systems have power “down the line” others have their panels or stations that are locally powered.
Digital - A mode by which analog audio is converted to a digital stream for transmission down cable or fiber.
Analog - The basis of most intercoms. Analog audio travels as a signal that is a modulated voltage based on the input of, for example, a microphone.
Intercoms Parts
Typical intercom systems are made up of a few basic parts; a base station, belt packs, and headsets. On wireless systems, the base station typically functions as the master control for the body packs. Wireless body packs send and receive via the base station, as opposed to directly to other body packs. In a wired system the base station provides power to the entire system. Most wired intercom protocols function over XLR cable. This cable connects each station or body pack back to the base station or each-other.
Wired vs. Wireless
When it comes to intercom, the wired or wireless arguments pretty much follow along the same line as wired or wireless microphones. Wired systems are cheaper, easier to expand and very unlikely to have outside interference. Your typical wired intercom system is also pretty much indestructible. I have a wired system from PI, now operating as Pro Intercom, that may be older than I am, and it still works perfectly. All the parts are banged up, dented, and missing screws; I purchased it VERY used, but it still shows no signs of beginning to fail. Wired intercoms just work, it’s that simple. The cost savings is not trivial, but you will need to factor in the cost of the cabling, which is often overlooked. Wired systems need to be well planned and points need to be established early in the building process. As with most things, if you are putting intercoms in, put more than you need. It would shock you how fast small system becomes totally inadequate.
When I started in production, wireless intercoms were the caged canaries of the production coal mines. They were the most fragile and most likely system to fail. That, however, was decades ago, and today wireless intercoms are far more robust. The Clear-Com Tempest system we have in my home church has been in place for about five years, and I can measure the amount interference over that time in seconds. I wish more of my gear had that level of reliability.
Wireless intercoms are, however, more expensive. They also are less flexible when it comes to expanding. And because they often operate in the same spectrums as some microphones and wireless routers, the opportunity for interference can’t be ignored. This is especially true now that the FCC has squeezed the available spectrum. Many wireless systems come in small lots of four or six users and some cannot be expanded beyond that. The good news is the standards for many, if not most, intercoms are close to the same. So you don’t have to go straight wired or wireless. Typically these systems can play well together.
Simplex, Duplex Party-Line, and Matrix Pro/Con
Most intercoms fall into one or more of these categories, and there are advantages and disadvantages to each. Simplex, for example, is typically a really cheap and easy solution for intercom. A simplex intercom is essentially a one-way street; you can only be talking or listening. Thus, only one person can talk at a time. As a result, if two people try to talk at the same time, "who heard what?" is going to be a guess. Transmission is typically started by someone “opening” their mic. These systems are typically PTT, and as long as the mic is “open” you can talk, but you cannot listen. As a result, these systems are not great for critical situations where good two-way communication is a must. That said, they can be good for small productions or situations where multiple people need to listen but only one person ever needs to talk; for example, a stage manager and stage hands. Eartec makes a small affordable simplex system, called the Scrambler which operates in simplex.
Duplex, as you might have guessed, means you can talk and listen at the same time. More than one person can talk at a time and everyone can hear both or multiple speakers. This is good for larger productions where communication needs to be a two-way street. However, unlike a simplex where the director can keep his mic open and no one else ever gets to interrupt, in a duplex system it is possible for people to interrupt or talk over you. So while it is better for communication, it can also become difficult to understand what is happening if multiple people are talking at once. Many intercom manufacturers make wired and wireless version of this type of intercom. Wireless systems include including Clear-Com’s DX and FreeSpeak, Pliant’s CrewCom, Eartec’s UltraLITE and Riedel's Bolero system. Wired systems include: Anchor Audio’s PortaCom, Clear-Com’s Encore, Pro Intercom’s Econocom,
The matrix intercom is the last type and it is the most complicated to explain. Typically these systems are far larger and farther reaching than conventional party line systems. Unlike duplex, where everyone is in the same “conversation” or there maybe a few selected “conversations” going to in different channels. In a matrix intercom system, anyone can talk to anyone privately or talk to a group, and the whole system can be dynamically controlled. So rather than having just A or B channel, someone could be talking to a group then get a request for a “private channel” which could be just two people. In some larger systems those channels could include just the one other person, or other people from other groups. Everyone is point-to-point so there can be as many conversations as the system supports and people can be included in some, but not others or vice-versa. Many matrix intercoms can use proprietary hardware like multi-function panels and interface devices, but many have virtual interfaces as well. As a result some matrix intercoms can be hardware-agnostic and run on anything that can handle the software or ingrate to the hardware like; touch screens, tablets, phones, walkie-talkies and regular wired intercom systems; basically anything. As you can imagine, these systems are the most expensive and toughest to maintain, but they also have the largest flexibility. In churches, this type of intercom is required if you want to have constant communication between campuses that are across town, across states, or across the country.
In today’s production-oriented churches, intercom systems are a must. As soon as you have multiple camera operators, it’s time for a good, solid intercom system. I hope this article has equipped you with some information to start figuring out what your needs are and what you should be looking for in an intercom system. The options are plenty, the form and function are radically different across manufacturers, and the price points runs the gamut. The real deciding factor is a balancing act of need versus budget. I always think you should put in more intercom than you need, because you will grow into it. I can honestly say in all the time I have been in production, I have never heard someone say “You know what we need? Less intercom.”
