Classroom audio systems (Part 2 of 2): Installing your system

The big day has arrived! You’ve received your Lightspeed classroom audio system! If you have already torn open the box in excitement, I hope you didn’t feel overwhelmed by the cables and gadgets you saw inside. In fact, if you’ve ever hooked up a home stereo, you are going to find this installation nearly as simple. Before we begin, let’s gather our necessary tools: a utility knife (to cut speaker wire) and a ladder (apparently OSHA doesn’t approve of you stacking chairs on top of desks). Now let’s get to work!

Start by planning your setup: If your classroom has a drop ceiling, you should put your IR receiver (that domed-shaped device) in the center of your ceiling. If not, I suggest mounting it high in the center of a wall in your room, close to where you will place the Lightspeed amplifier. I suggest putting your speakers on top of a cabinet away from where you usually stand in the classroom. That way, your voice will be present in an area you typically are not. You may want to keep your amplifier close to the speakers, but this isn’t necessary. Just keep in mind that you may have to use more speaker wire or creatively conceal wires if your amplifier is placed farther away from your speakers.


Fig. 1 – Connect the IR receiver to the metal drop ceiling support.


Fig. 2 – Connect the IR receiver to the amplifier (you can connect to any of the sensor inputs on the 700IR).

Once you’ve planned your setup, you need to attach the IR receiver to the drop ceiling or a wall. If you need to mount the receiver on a wall, use some 3M all-weather permanent mounting tape. I have found that this works wonderfully, even on cold cinder block walls. Drop ceiling installations are a little more time consuming, but look nicer. The IR receiver has a white clip that can attach to the metal drop ceiling panel support. While standing (carefully!) on a ladder, simply lift a drop ceiling panel in the center of your classroom, and rock the clip onto the support. Look where the IR receiver’s wire is hanging and cut a small piece out of the drop ceiling panel so that the wire doesn’t get pinched by the support (Fig. 1). Now, the most difficult part of the installation: running the IR receiver cable to your amplifier. Connect your coaxial cable or mono RCA cable (the type of cable you need depends on the SR-70 IR receiver you have) and lay it on top of the drop ceiling panel you have moved. Take care to align the cable so that it goes through the hole you cut in the panel. Replace the panel. Obviously, you will have to work your way across the room moving panels and pulling the IR receiver cable over to your amplifier. You may have to cut another hole in the panel closest to your amplifier so that you can drop the cable down to it. Finally, plug or screw the cable into the sensor input jack on the back of your receiver (Fig. 2).

It’s time to run wires to your speakers. Make sure the amplifier is turned off before you do this. Strip off 1/4″ of speaker wire sheathing using your utility knife to expose both wires. A tip: You can connect either wire to the positive or negative inputs of the amplifier, but make certain that the same wire is connected to the correct polarity on the speaker. Connect the wire to the amplifier (the 700IR uses spring-clips and the 820IR uses screw connectors). Also, on the 700IR receiver, you’ll want to make sure the “Speaker out” switches are switched to “On.” Run the wire to your speakers and connect them. If you’re trying to make your installation look professional, buy some 3M cord clips to keep your speaker wires looking tidy.


Fig. 3 – A selfie to demonstrate proper microphone positioning.

Now that everything is connected, it’s time to power on your system. Attach the lanyard to your microphone and place it around your neck. For best audio, pull the lanyard tight enough so that the microphone is at the base of your neck (Fig. 3). Flip the switch on your Lightspeed amplifier, turn on your microphone, and start speaking in your “teacher voice.” You can fine-tune how loud you want your system to be using the controls on the front of the amplifier. Both the 700IR and the 820IR have equalizers on the back to adjust the tone of your voice. I haven’t found much of a need to adjust these settings, as I’m pretty certain that no amount of equalization will make me sound like James Earl Jones.

That’s really all there is to it. Down the road, you might consider purchasing a second microphone to pass around the classroom for your students to use when they are called upon to speak. If you do, just make sure that microphone is switched to the “A” channel and the other is set to the “B” channel. You and your students may feel awkward at first using a microphone, but I encourage you to stick with it and use it every day. Soon, you’ll understand how much better your teaching and student learning can be with a little audio enhancement!

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