Tutorial: Capturing Soundboard Audio for Live Event Video
Connecting your camcorder to an external microphone or soundboard is a critical skill for any event or corporate videographer, though it can be surprisingly challenging, making it an exercise best performed well in advance of the actual live event. In this article, I’ll walk you through the process, beginning with the assumption that your camcorder has XLR connectors and that your camcorder’s manual is handy.
First I’ll walk you through the process of connecting a microphone, then a soundboard. I’ll demonstrate connecting my Canon XH A1 to a battery-powered Azden shotgun microphone, but I’ll keep reminding you that while the procedure will be similar for most camcorders, the connections and settings will differ.
Connecting Microphone to Camcorder
Step 1. Physically connect the microphone to the camera.
If you’re connecting two XLR inputs into the camera, this is simple: Insert the left cable into Channel 1 and the right in Channel 2. If you’re connecting a single XLR connector, typically you want the audio to flow to both tracks. Even if you’re encoding in mono, this prevents errors such as audio registering on only one side. In this case, with the XH A1, you would insert the cable into Channel 1 and use the switch shown in Figure 1 to send the audio to both channels.
Figure 1. Telling the XH A1 to send the audio received from Channel 1 to both channels.
Interestingly, with my Panasonic HMC150, you’d insert the cable into Channel 2 and use a different control to send the audio to both channels. The critical bit here is that you should hear audio in both ears with the mandatory headphones and see audio in both tracks on the camcorder display.
Step 2. Turn on phantom power if the microphone needs power.
The XH A1’s controls are in front of the XLR jacks as shown in Figure 2. If you’re working with a microphone that supplies its own power, or a line feed from a soundboard, you would turn phantom power off. The Azden is battery-powered, so I turned off Phantom Power.
Figure 2. Here’s where you turn on phantom power when needed.
Step 3. Turn the microphone on (if necessary).
Don’t forget this stage or you’ll waste several minutes figuring out why you’re not hearing anything in your headphones.
Step 4. Switch the camcorder from the internal microphone to the XLR connection.
This is very camcorder-specific (Figure 3) -- sometimes performed via switches on the camera body, sometimes via menu options. Note that if the audio is too faint, I can boost XLR gain by 12dB using the XLR Gain Up control.
Figure 3. Changing the XH A1’s input to XLR
Step 5. Select line or microphone input.
Microphone input is weaker than the input from a soundboard or other similar device. To handle both, cameras have microphone/line switches that let you choose the input. In this case, since I’m connecting to a microphone, I’ll choose Mic (Figure 4). Note that if you’re connecting to a microphone and don’t hear anything in the headphones, it may be because you’ve got this switch configured to Line. If you’re connecting to a powered device such as a soundboard, choose Line input.
Figure 4. Choosing between Line and Mic inputs
Step 6. Enable attenuation, if needed.
Sometimes in either Line or Mic mode, the signal is too powerful for the camcorder to handle without distortion or too much ambient sound. This is the case with the Azden shotgun microphone, so I’ve enabled attenuation (Figure 5), which reduces the incoming audio levels by 20dB. How do you know when the signal is too hot? After you enable manual gain control and set the volume controls at mid-level, if the volume is bumping against the top of the volume meter, you should try attenuation.
Figure 5. Attenuating the signal from the Line and Mic inputs
Step 7. Choose your gain control strategy: manual or auto.
The switch at the bottom of Figure 6 controls whether I use automatic gain control, where the camera controls the volume, or manual, where I use the two dials above the switch to control volume. Typically, if I’m driving only one camera in a fairly static setting, such as a seminar or speech, I’ll use manual gain control. On the other hand, in dynamic setting such as a concert where I have to continually try to follow the action and adjust exposure, I’ll usually go auto.
Figure 6. Choosing between auto and manual volume controls.
Note that the old complaint about auto gain control was that the camera would boost gain during silent periods, creating audible noise when it’s supposed to be quiet. However, this isn’t a behavior I’ve noticed with any of my prosumer camcorders. If anything, the camcorders are much faster to adjust to changing levels than I am, and they are always paying close attention.
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