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Fundamental Decisions: Automixer VS Console Mixer

Whether upgrading a present sound system or starting the design for a new sound system, there are some fundamental issues that must be addressed. The sound system must be a technical match for the building, and it must be a match to the users. The most fundamental decision has to do with use. Will the installed sound system be run by an operator, or, will the system operate automatically?

In the 1950’s, many sound systems were all the same. Installed or portable, one four channel mixer-amplifier drove recess mounted 12 inch loudspeakers to the right and left of the front of the sanctuary. The beige grill cloth more or less matched the plaster wall. The sound was larger than that produced by the celebrant/minister. The neckloop microphone was wired to one of the four inputs, as was the pulpit. Operation of the system was set-and-forget.

This scenario was not all bad. Many churches do not have, nor do they need, a sound operator. Do you need one? This fundamental decision should be the basis for your system design .

Matching the loudspeaker to the room is one of the great technical challenges in church sound system design and implementation. The box loudspeaker solution may not be an exact fit, but they have resulted in a demand for sound system control. So many churches have sound systems that are prone to feedback that oftentimes they consider appointing an operator.

High fidelity loudspeakers, too many open microphones in the room, high SPL (Sound Pressure Level) demands and other requirements such as playback audio have added to the realization that a mixer is needed at the back of the room.

The human issues of the sound system are complicated by appearance. What is best for the user may not always be the flashy chrome plated stylized devices. Having an operator stationed at the rear of the sanctuary not only has a professional appearance, but can also give the worship staff a feeling of security. This feeling of security is either reinforced or damaged by the skill of the operator.

In great art, less is more. In sound systems, less is more. The common vernacular expression of the artistic maxim is KISS. KISS is the contracted expression Keep It Simple, Stupid. This means that the less complicated the sound system, the more reliable. It may also mean that if too many things are involved, the operator cannot easily manage them.

Begin the system design process by asking how many microphones the church really needs. How many are required for the spoken word? How important is the spoken word to the ceremony? If the service is traditional spoken word with one celebrant, and if music is secondary, the system may only require a podium microphone, a microphone at the table and a musician microphone mixed to loudspeakers which match the room.

Few microphones means fewer decisions. Fewer decisions mean that less can go wrong from the technical (and the human) standpoint.

If more musicians are involved, or if the musicians require their own loudspeakers so they can hear, then more control issues arise. At this point, an operator may be needed to make the decisions that an automatic microphone mixer cannot. The church may leap to the conclusion that a manual mixer is needed so an operator can control all of these functions.

Although it is not generally wrong to install a manual console mixer, it may not be right. The console mixer is only as good at its operator. The greater the training and experience of the operator, the more effectively the service will be run. The operator must use as little gain a possible, select the appropriate loudspeaker destination for the signal and equalize where necessary- not where unnecessary. As an operator’s skills build, so does his or her value. Training and retaining a skilled operator is often a challenge, but worth the effort!

When a console is installed, someone must be there every time the system is used. Small events, daytime events, and special events (like weddings and funerals) must be covered, as must the regular weekend service. Due to these special needs, sometimes a church with a need for a console mixer and operator will install a small automixer connected to designated microphone receptacles. When a one, two or six microphone event happens, the user simply turns on the power and the system operates automatically, at a preset level, or the system is turned on and operates at one of three preset levels: lower, medium and higher.

So what is the fundamental decision? Is the sound system to be run by an operator or not?

I suggest that you decide in favor of an operator if:

1. You need a lot of open microphones, and some must be lowered throughout the service to prevent feedback.

2. There are many destinations for the signal which must be manually controlled because no automated system can respond to appropriate sensors or other program selecting inputs.

3. You have an ongoing budget to pay the help. If the help is voluntary, you need to be wary for reasons of competency, availability or training/experience.

4. You have enough operators to construct a schedule covering all services with regular and contingency operators.

Other reasons may also develop, but these prime reasons generally drive the decision as to whether or not you should go with an operator.

When can an automixer work? Traditional automixers can work well in applications where an adjustable NOM count (Number of Open Microphones), adjustable compression and adjustable tail are used. These adjustments can be effective and also ineffective. Remember- a guitar cable which has been around the world eight times, stepped on, dropped in puddles and used as a bungee cord to keep a van door closed- can easily fail. Any small failure renders the entire system at fault. The problem can be small or large, and still have the same effect on the confidence of your audience.

Digital mixers are more sophisticated than the analog mixers. Each input can have equalizing coloration control, can send signal in a variety of ways, and can do specialty functions. For example, a single digital mixer can be configured into multiple automixers with submasters and master volume controls. One particularly useful function is to link NOM counts. The speech microphones and the music mics can operate differently, have different equalization, and different loudspeaker groups- but share a common NOM count to limit feedback potential. This is very helpful for controlling choir microphones in particular.

Fundamental decisions frequently relate to the users. How will this system be used? Do we have the personnel to operate a manual console, or, should the system be automatic? Should the system be built for future expansion, or should the system be replaced in the next four years? Will an operator be used for all events, or, will the system be unattended?

One other factor enters into the mix. Analog rackmount mixers have knobs on the front. Digital rackmount mixers do not have front knobs. The digital mixer is programmed and preset. If any controls are needed, they are programmed through an interface device. That interface device might be a four button preset select, and/or a volume control. People will tend to turn knobs, because knobs are attractive. People will turn knobs looking for a response. Once turned, said knobs will likely not be returned to the position where they were preset. One of the greater arguments for digital mixers is that without knobs, fewer things will tend to go wrong.

Among all the possible fundamental technical issues that need to be addressed, the operator issue may well be one of the most important. Hopefully this article has given you some food for thought when planning to make this fundamental decision.

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