Building Dynamic Multimedia Courses Part IV

Building Dynamic Multimedia Courses Part IV

Once you’ve mastered the art of fundamental lighting it’s time to focus your attention on the audio. Think about it, you just spent a great deal of time and effort perfecting your shot, your content is well planned and engaging; it can be a painful lesson when you go back to review the footage and find the audio is no good. Sometimes it sounds hollow and you think, “I’ll just bring up the levels in post-production.” The problem is when you bring up the levels, you also increase the ambient noise of the room– the hum of the refrigerator, the reverberant echo, the fan from the computer – even just the air conditioner can make a good recording sound bad. In this segment we’ll cover some key steps to creating good clear audio and give you a couple different choices to make when purchasing your microphone.

Basic video-based training modules do not require Hollywood quality sound and expensive equipment. However, you do need to follow the same rules the pros do when recording audio for your training materials.

Here are a few steps to get you going in the right direction.

First, you need to focus the microphone on the subject. Three microphone types you should consider are the clip-on lapel mic, also known as the lavaliere, the headset mic; which many people use for Internet phones, and the shotgun mic – that’s the long, skinny mic you sometimes see dipping into the camera frame on TV shows and feature films. For a video-based training, course you will typically choose a lapel mic. That will allow you to get the mic as close as you can to the source without detracting from your shot.

The closer the mic gets to the sound source, the better. (There are exceptions, like shotgun mics that have a certain minimum distance for the best sound.) Think of the mic as a flashlight illuminating the subject. Now think, every time I can halve the distance, I can double the sound level. Read that again. It’s crucial to understand that getting the mic as close as you possibly can to the subject is the best way to achieve the results you’re after. A headset mic works well, but because it sits on the head and in front of the mouth it could be distracting for your viewers. For video-based training, we recommend you use the lapel mic; this will give you the most versatility. If you do not plan to deliver video of your presenter in your training go with a USB headset mic, it’s going to be your cheapest route, and viewers will never see it!

If you are using a shotgun mic you should know a couple of things. First, shotgun mics are generally more expensive. So make sure you can afford them in your budget. Second, shotgun mics are generally used to pick up more than one person’s sound. If you need to capture a scene with multiple people talking, a shotgun mic will be the best choice. Otherwise, you will create more work for yourself in editing because you’ll need to clean up of all the other sound the shotgun mic will pick up.

Second, always record your audio and video at the same time using a camera or a computer. This will ensure that your audio and video remain synched. It’s very difficult to synch your video and audio after it has been recorded. It can be done, but we don’t recommend it.

For sections where you will have voice over graphics, record the audio right into your computer. Microphones generally use three different connectors: XLR, USB, or FireWire (also known as i.Link, 1394a, DV). XLR plugs and sockets are used mostly in professional audio and video electronics cabling applications. Universal Serial Bus (USB) is a serial bus standard to interface devices. USB was designed to allow peripherals to be connected to computers using a single standardized interface socket to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). FireWire is very similar to USB in that it too is a serial bus standard to interface devices. FireWire however, was designed more specifically for Audio/Video than USB. Both USB and FireWire are good choices when connecting Audio/Video devices to your computer. To record XLR-based mics directly to a computer you’ll need XLR to USB cord or a FireWire converter box. You can talk to someone at your local electronics store about finding the right cord for your system.

Always record at least 30 seconds of test audio before you record any actual content. Recording test audio will help you identify any issues you may have with your levels, and allow you to make adjustments to volume and mic placement before the actual recording. It will also provide plenty of ambient sound that you can use during the noise reduction process which we’ll discuss later in the segment.

The Third step is editing. Once you’ve finished recording your voice work, the editing begins. Don’t let this stage frighten you. Although it can be a little overwhelming at times, editing your audio with today’s tools is much easier than it used to be. There are many audio editing applications you can choose from. Most importantly, choose the one that best fits your budget. If you have followed good recording steps, you won’t need to spend a lot of extra money on the best audio editing application. Most video editors have audio editors built into them and they will work perfectly for editing your audio. Some editing applications have built-in filters that allow you to reduce the background or ambient noise in an audio file. The noise reduction process allows you to eliminate unwanted background sound so the listening experience is clearer. This is done by selecting a segment of audio in the timeline with just background noise and telling the software to eliminate those sounds from the rest of the audio. Each software application will handle this in its own way, but noise reduction is a fairly standard editing process. Noise reduction can help reduce ambient noise, but it’s not going to compensate for major distortions.

Additional Tips

Always wear closed-ear headphones to monitor your audio. Models such as the Sennheiser HD-280 Pros or the Sony MD7506s are industry standard. Use Dr. Scholl’s non-allergenic Mole Skin when concealing lapel mics on your talent. This allows you to adhere the mic directly to the skin or under clothing. Fold the Mole Skin over the mic creating a mini tunnel.

Final Thoughts

Thanks to some great post-production software, the old saying of garbage in, garbage out doesn’t have to apply to audio. Good audio editors can do wonders to give the recorded sound warmth or brightness. But you are always better off starting with good quality. If you don’t have the right software and a talented post-production team, then you’d better get the best recording quality you can upfront. The most important thing is to record a strong, clear, signal with limited background noise. Good microphone placement and good recording levels will make a big difference. Another hint – if your talent stumbles over a word, or a siren goes off in the background, don’t be afraid to stop and rerecord. Rerecording a line while you are in the process is one of the easiest fixes you can make.