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PA systems - portable PA systems, accessories

part 2 - choosing the right PA system

"Where you are is what you get"

In Part 1, I covered the fundamentals -- especially audience size -- which you need to consider when choosing a PA system. In particular, the size of your audience is the single most important determinant of the power supply (Wattage) needed to run your PA system. I would now like to focus on the next set of criteria for making an informed decision:

  1. “In what type of venue will you use your PA system?”
  2. “What type of program will you be producing?”
  3. “What special features are needed to make your program work?”
In each of these cases, I continue to emphasize getting the most bang (decibels and fidelity) for your buck! With modern electronics you can do a lot even on a limited budget.

Two Main Types of PA Systems:

Once you have addressed these questions you should be able to make a quick decision between the two main types of PA systems: a self-contained PA system or a powered mixer with PA speakers.

Most PA systems that are available commercially are self-contained or 'portable', meaning that they are not meant to be permanently installed (although they certainly can be).

Self-contained PA systems plug into a wall outlet (AC powered) and/or may operate from a rechargeable battery pack (DC powered). They usually include an amplifier with a mixer and built-in speakers that will handle up to six channels.

The Powered Mixer with PA Speakers:

A powered mixer system is a mixing amplifier which handles more than 6 channels and requires separate, sometimes multiple, speakers. This system is most often found in permanent installations such as a conference facility, and has the following advantages:
  • More than six separate channels (as high as 256)Highly adjustable equalization controls (lows, mids and highs)"Graphic EQualization", special effects and digital processingVaried program source inputs (Cassette, CD, DVD, PC, AM/FM, TV/VCR, Satellite, Telephone and Cable)Multiple and high-powered speaker arrangements (stereo and quadraphonic)Optimal speaker placementSophisticated recording capabilities
  • On-site, trained technicians
For permanent installations, AudioLink Services can advise you on the best configuration for your room, assist you in your choice of equipment, provide the required equipment and assist you with the installation.

The Self-Contained Portable PA System:

Now, let me return to the discussion of a self-contained portable PA system.

Let's use the questions outlined above to determine what you need, and, more importantly, what you don't.
1. “In what type of venue will you use your PA system?”
First, let's get back to the issue of how much power you need. The answer to the first question significantly helps.

Power is rated in Watts (W), and a general rule of thumb is 1 Watt per person. The venue you are using can, however, impact this 1 Watt per person rule by as much as 50% either up or down. Most portable PA systems have stereo speakers so your Wattage is cut in half. Therefore, if you want to cover 150 listeners you will need 75 Watts per channel. If you are working smaller rooms or crowds, you usually don't need more than 50 Watts. Overcoming loud conditions -- especially out doors -- or larger venues may require 250 Watts or more per channel. The rule of thumb only works in "optimal" environments.
2. “What type of program will you be producing?”
Next, let's focus on applying your answer to question number two to determine the number and type of channels or jacks appropriate to the program you are producing.

Channels come in two varieties: inputs and outputs. Each program source you require for your presentation, be it a microphone for speaking or singing, or an accompanying cassette, video, CD or DVD will need its own input channel. Channel inputs generally require 1/4 inch (headphone) jacks, XLR jacks (three pronged and circular) or both. RCA jacks are still a mainstay in the industry, despite their limitations. Make sure that the microphones and other external program sources you need can be properly connected to the PA system you are considering.

In addition, you need to be sure you have enough input channels for your desired purpose. For example in a Q & A set-up, with audience participation, you need an input channel not only for the speaker, but also at least one additional input channel for each audience microphone. The question of portability arises in the context of wired and wireless mics which I will examine in a separate article.

Output channels are necessary for each speaker, headphone, recording and auxiliary device. These again come in multiple types, mainly 1/4 inch, XLR or both. Remember that you need one output channel or jack for each device desired.
3. “What special features are needed to make your program work?”
Let's examine the options that are minimal to any program and then what extras might be needed to cover your special needs.

Some manufacturers sell all-in-one solutions with mixers, microphones, speakers and cables for a single price (e.g. Fender Passport Deluxe 150 or Deluxe 250). Other manufacturers, like Anchor Audio, allow you the flexibility to mix and match many different accessories -- but remember you need to add the cost of these a la carte purchases to your budget. (Anchor Audio also sells some all-in-one solutions like the Liberty and Xtreme, but their true strength lies in maximizing flexibility.)

For most purposes you need at least four types of accessories: speaker stands, carrying cases, cables and microphones. Let's take each of these in turn. Speaker stands and carrying cases tend to be specific to manufacturers and PA models so my best advice is make sure you order the correct, compatible accessory. (You can always ask us for advice.) Cables are more generic and come in varied sizes -- 1/8 inch (mini), 1/4 inch, XLR, RCA and AC -- and in varied lengths. Typically cables are 25, 50 or 100 feet in length. Order the size and length you need for your venue. AudioLink offers standard cables and, by special order, can provide you with custom cables.

Ok. So far so good. How about microphones? Well, I plan to do a full size article or two about microphones in later issues, so for now - a few choice words... Testing, testing, 1, 2, 3... Hey is this thing on?

There are two basic types of microphones: wired and wireless. Wired microphones are both affordable and reliable. A third advantage is that they are (usually) included in your PA package. Thus, the often underappreciated wired mic is a great solution if you do not require a lot of mobility. Just plug it in to one of the available channels on your mixer and go as far as the cord will take you.

This said, for flexibility, interaction and audience participation, a wireless microphone system can't be beat. Wireless systems are usually purchased separately from your portable PA system. Just make sure you can plug it in! A wireless lavaliere (lapel), headband or collar microphone system consists of a radio frequency transmitter attached to the microphone, usually called a bodypack, and the receiver, which plugs into your PA amplifier. Some wireless mics include both of these components while others require purchase of the components separately. A wireless hand-held microphone usually acts as the transmitter, which broadcasts a signal to its receiver plugged into the PA mixer. Remember, when using more than one wireless microphone, each must operate on a separate frequency to avoid interference.

Other PA System Accessories vary depending on the system you buy and your particular needs should dictate the components you purchase.

For instance, let's consider lecterns. A portable lectern PA system is very useful due to its flexibility. It can be a simple podium tabletop housing with no electronics, all the way up to a self contained, multimedia PA system that can project your program to an audience of 1000 attendees or more. The value of a lectern is that it helps separate the speaker from the audience (which can be a consideration for both security and prestige), and also assists the speaker in making his/her presentation with features such as shelves, lights, and control panels for audio visual presentations.

Auxiliary devices, such as recorders and CD players are important items to consider if you want to provide multimedia options and programming. Adding background music to a presentation is very effective and entertaining.

Make sure your equipment choices have the ability to adapt and grow along with your present as well as future needs.

There are many more features of PA systems that are available including: graphic EQ, special effects, digital processing and mono-bridging. And guess what - mixers with these features are available through AudioLink! However, here's a real tip: make sure its got an auxiliary out (for hooking up to other systems or a recorder) and reverb - the worst sound in the world is greatly enhanced by reverb. Fortunately, these are generally standard features.

Obviously, there is a lot to consider when buying a PA system. Hopefully, this article and the previous one have given you enough knowledge and confidence to help you get started.

PART 1: "Size Matters"
PART 3: Hand held PA's and Megaphones: "There Is No Such Thing As A Small Audience"

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