Technology marches on. Things once analog are now digital . . . wireless communications are becoming much more prevalent.

How information, ideas, plans, and possibilities are communicated from your mind and laptop computer to the eyes and ears of your audience requires digital to analog to human conversion.

This column is about that conversion. What factors contribute to effective group communication? What factors diminish these efforts? Here you'll find insights and perspectives on audiovisual and other sensory elements that affect teaching and learning at your technology meetings. These elements can mean the difference between a successful meeting and a disappointing one.

The first two columns will be an overview of the subject and a checklist of issues to consider as you talk with facility managers and their conference services representatives. This time, I've covered sound and projection systems, and in the next issue, I will walk through connectivity and AV services. Subsequent articles will expand on these issues and, we hope, answer the questions you send us.

Audio: Sound System * Does the facility have a built-in sound system? How is the quality? How old is it? Who operates it? If the facility recommends a portable sound system, ask why. Is it because the system will enhance your meeting or because staff doesn't trust the built-in system?

* Does the facility accommodate the Americans with Disabilities Act assistive-listening requirements?

* Have the facility demonstrate the sound system using the type of microphone that will be used during the meeting. Speak into the mike from a distance of six inches and listen. Have someone else speak into the mike while you walk around and listen.

If it's a portable system, listen especially closely, positioning yourself about midway in the room. Listen for echoes (echoes) from (from) the (the) back (back) of the room that will reduce intelligibility. Remember that during a demonstration, you're listening intently for a short time. Your attendees will be listening for hours. Seemingly inconsequential quality defects will become irritating over time. And keep in mind that what you're hearing is the facility's best.

Acoustics The single most important factor that defines quality in the minds of our listeners is "signal-to-noise ratio." Background noises reduce this ratio and make it difficult for an attendee to hear. The noise can come from many sources: from echoes to air-conditioning systems to sounds from the meeting next door. The more noise in the room, the greater the stress and the more concentration required to listen to a presentation.

Visit the facility during an event. Listen carefully. Does the room sound hollow or boomy? Have the facility turn on the air conditioning to maximum. Ask someone to stand 30 feet away and talk in a normal voice. How easy is it to understand them? Go to the adjacent room. Have the facility turn off the lights and look for light leaks around or under the movable walls. Each light leak you see is a sound leak.

Visual: Screen Is the projection screen located appropriately? Can it be moved or is it built-in? Is it the right size? Is the audience seated in good viewing range of the screen? One rule of thumb is to take the distance between the screen and the farthest viewer and divide by six (for data) or eight (for video). The result is the minimum height of the screen to ensure your viewers will be able to distinguish between a B and 3 and 8 and H on a spreadsheet. The closest viewer should be no closer than two times the screen height from the screen.

The bottom of the image should be high enough (42 to 48 inches off the floor) so that those in the back can see over the heads of those in front. The dispersion of the image is typically 90 degrees for front projection and 60 degrees for rear projection. (Dispersion is the angle from the farthest left to the farthest right that a viewer can see a correct image.)

Are there light sources that will wash out the screen? Do the windows have blackout curtains? Can the ceiling lights be controlled easily? Will the air conditioning cause the screen to wave?

Projection Video/data. What is the quality of the video/data projector in terms of brightness, native resolution, and contrast? What technology is it using? CRT (cathode ray tube), LCD (liquid crystal display), ILA (image light amplifier), DLP (digital light processor), or DMM (digital micro mirror)?

If it's a CRT projector, is it permanently mounted or portable? When was it converged last? (Converging a projector is the process of focusing and adjusting the optics and color balance of the projector to make the image as clear and sharp as possible.) If portable, will it be converged for this event? How will it be protected from movement? Does the facility have an appropriate computer interface or scan converter?

Overhead Projector. Does the overhead projector have a spare lamp? Does it work? Can a document camera (a video camera positioned over a table or platform that permits the presenter to place an object or exhibit and have the image displayed on the video projector) be used in place of the overhead projector? This can replace traditional overhead or opaque projectors and uses the video/data projector to display the image. Is the power cord taped or dressed away from traffic?

Slides. Can the slide projector be located at the rear of the room to keep the noise away from attendees? Is the remote control wired or wireless? If rear projection is anticipated, ask for an image-reversing mirror so presenters don't have to flip their slides.