A/V Basics: When Do You Need a Mixer or Amplifier?

The explosion of 20th century technological advancement propelled us into a new millennium with more of the same. Businesspeople, whether self-employed or part of a Fortune 500 firm, can now avail themselves of a tremendous collection of high-powered computers and potent software programs to create compelling proposals, brochures, sell sheets and other marketing/sales collateral.

It is the area of presentations that questions abound: How do I connect everything? How do I control the PowerPoint or Keynote presentation itself? And, on a more basic level, how can I make sure all my sights and sounds work right, and that everyone can see and hear the presentation? This is where an introduction to audio/visual (A/V) basics can pay you great dividends, namely, a successful presentation.

So, you’ve created your PowerPoint or Keynote presentation, put in your soundtrack, practiced the slideshow and are ready to go. Now what? Well, now you select any of the modern projectors on the market and get a screen, because you’re just about ready.

Projector Progress

Multimedia projectors have come a long way in the last decade or so. Most models cover all the bases for connecting nearly any device that has a video output; there are VGA ports for connecting computers, composite video inputs for connecting things like VCRs and, in the best models, component video, S-video and other inputs as well. Connect your Macintosh, PC, VCR or other device to the projector, and you’re ready for sights – but what about sound?

You will most likely be working with an audio track that is part of your presentation file, which does simplify things. Some other time we can discuss how to combine different sound sources with your video source, a task that requires a “mixer” to handle multiple audio sources. For now, though, we’ll continue with setting you up to show your all-in-one audio/visual presentation. The next question is, How big is the room?

Sound Judgment

If you are making a presentation to a group of six or eight people in a normal-size conference room, your projector’s built-in speakers should do the job. If you are making your presentation to a larger group in a larger room, however, you need to consider ways to amplify the sound for all to hear.

Modern projectors have a variety of audio output options, from basic RCA connectors (two, for stereo L and R) and 1/8-inch mini-jacks to S/PDIF (Sony/Philips Digital Interface) digital on higher-end models. For years, the main way amplification has been accomplished is by connecting an amplifier to the appropriate projector output, and then connect speakers to the amplifier.

Today we have a simpler solution. By building small amplifiers into the speaker cabinets, audio manufacturers created an entirely new product type for recording studios, stage managers and, of course, businesspeople making presentations. Known as amplified (or bi-amplified) monitors, these units attach with everything from old-fashioned speaker wire to ¼-inch jacks – and there are plenty of adaptors around, just in case.

Just do your homework and you’ll be fine. To know whether or not you need more than the projector’s built-in speakers, test the presentation in the room if at all possible. And if you need to, add a couple of amplified monitors to the mix.