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.
When you’re pulling audio from a soundboard, the board jockey is making almost continual adjustments to volume that are nearly impossible to respond to, particularly if you’re trying to follow the action with your camcorder. Auto will make sure you don’t clip at the high end or record too faintly at the low end.
Step 8. Check levels with headphones and volume meters.
The final step is to plug in some headphones and make sure the audio sounds good. The volume meters on most prosumer camcorders will also tell you when you’re properly connected and when audio is only flowing into a single channel. You want the bulk of your recordings to appear in the zone shown in Figure 7, but you always want to err on the side of being too low, rather than too high. You can always boost audio volume in post (or at the encoding station), but if the volume controls continually push against the top of the volume meters, you’re clipping your audio signal, which causes distortion.
Figure 7. The volume meters on the bottom look just about right.
That’s the basic procedure. While it will vary from camcorder to camcorder, the overall structure should be fairly similar. Now let’s focus on connecting to a soundboard or similar line-powered source.
Connecting to Sound Systems
The basic procedure for connecting to a sound system is the same as the procedure defined previously, except that you use Line input rather than Mic. Easy peasy. Typically, if problems arise, they come from one of four directions.
Often the soundboard isn’t set up close to the camera position, which can be a real problem. If you ask about this early enough, typically the sound guys or event manager can run a cable over to your position, but advance notice is required because the cable will have to be taped over or buried. If you show up an hour before the show and start asking questions, it may be too late to get the input.
Another source of problems is when there simply isn’t an output that the soundboard can spare. If you get in touch with the sound guy early enough, you can work around this, often by getting some kind of splitter cable that takes the outgoing signal and splits it into two. Figure 8 shows the GLS Audio 6-Inch Patch Y Cable Cord that costs $9.99 at Amazon; buy two of these and you can split the left and right XLR outputs and create another output.
Figure 8. An XLR splitter can provide access to the soundboard.
The third source of problems typically relates to physical connections. Most lower-end soundboards use quarter-inch connectors out, which can be stereo or mono. If you have mono outputs, you can buy many different adapters to convert from quarter-inch to XLR, although stereo is tougher. Basically, every situation can be different, and sometimes you’ll need to buy some kind of adapter to get the job done. Figure 9 shows some of the adapters I’ve acquired over the years, but I still call a few days before the show, ask about the connections available, and try to test the connection a day or two before the event.
Figure 9. Some of the detritus bought to connect to multiple soundboards
The fourth source of problems, which I’ve witnessed only from afar, is when the signal coming from the soundboard is too hot for the camera or other capture device to handle. Here you need a signal attenuator such as the Shure A15AS (Figure 10) that has switchable values for a 15dB, 20dB, or 25dB reduction in signal strength. To make this work, connect it between your output and your input, which obviously means that you suddenly need two cables.
Figure 10. Attenuators reduce the levels coming from the soundboard.
I saw an attenuator like this save the day at the J Street convention I helped produce in March 2012. Fortunately for me, it wasn’t the feed coming into my camera; it was in a different ballroom.
Without the attenuator, the signal was too powerful for the camcorder it was plugged into, producing significant noise. This was fixed at about 11:00 the night before the convention, and if one of the sound guys didn’t have the adapter on hand, it would have gotten ugly. In short, when you’re streaming a live event and don’t control the sound, contact the sound guy as early as possible, identify the connections you’ll be given, and try to test the connection at least a day or two before the event.
Overall, the two absolutely critical resources every first-timer needs are plenty of connecting and testing time and the camcorder manual close at hand. Without both of these, you’re setting yourself up for a high-stress connection session with only a fair to middling chance of success.
The article is an adapted excerpt from Jan Ozer’s book Producing Streaming Video for Multiple Screen Delivery, which has three chapters dedicated to live event production. It appears in the October/November 2013 issue of Streaming Media magazine as “Capturing Soundboard Audio for Live Event Video Production.”