Introduction

This post is for those of you who are interested in a way to record a consistent audio level while moving all around the room teaching your classes.

I hope you have discovered the fact that you can record a video podcast of everything you are doing on your interactive whiteboard and upload it to the web for your students, their parents, and other educators. Both the Promethean Board and the Smart Board have built in recording software utilities, though they presently record at very low frame rates. I personally use ScreenFlow to record on my Mac. Windows users can use Camtasia. (Regrettably, Camtasia is markedly more expensive for the Windows users than ScreenFlow is for the Mac users.) Some interactive whiteboard models include a microphone in the attached projection unit. I know from personal experience that, on my Mac, this recording process will take less than an extra minute of your time (as long as you don't sit at the computer waiting for the file to export into a video podcast format).

The only real technical issue with recording this type of podcast is recording the audio. You want to be standing in front of your interactive whiteboard: writing, talking, pointing, clicking, dragging, highlighting, and teaching. You want to move around the classroom while teaching. So, while you're doing this, how do you capture the audio of your speaking so that it sounds really good?

Few things are as annoying as bad audio. As long as you are close to the internal mic in your computer, you sound fairly good. But the minute you walk away from your computer, for example: heading off to the interactive white board, the sound of your voice becomes so faint as to be annoying, even useless.

Solution: the wireless mic! This post contains several options. But before we go into the options, let's talk about a few things that can make wireless mic systems more or less expensive.

Cost Factors

1. Channels
The wireless mic broadcasts from the mic unit you wear as you move around back to a stationary receiving unit you plug into your computer (or sound system or video camera). If the wireless mic system only has one channel on one frequency it can broadcast on, it will be less expensive. The more channels and frequencies, the more expensive the system will be.

Having one channel on which to broadcast may not be a problem as long as no other stronger signals are nearby on that same channel. If other signals exist on your channel (a teacher in the room next to you with a wireless mic?), they may compete with your mic signal. You may hear those irritating static sounds, popping noises, or, if the signal is strong enough, whatever is being broadcast by the other source may completely replace your mic signal. Other electrical signals, such as electrical wiring or equipment, may also interfere with your channel. The option to change your channel (on both the mic and the receiver as they must both be on the same channel) reduces the likelihood of signal interference and noise but increases the cost of the wireless mic system.

Here's a funny and true story to illustrate. At school, one of our counselors was presenting to the sixth graders using an inexpensive wireless mic. A road crew was working outside in front of the school. Suddenly, the road crew's walkie talkie signal overpowered the counselor's wireless mic channel and what she was saying was replaced with an angry male voice yelling, "Get your *** over here right now!" Everyone in our theater was shocked and horrified into a stunned silence. Then, softly, a little sixth grader said to the counselor, "Does Dr. Tyson need to see you now?"

2. Range
I am unsure exactly how much range is impacted by the price of the wireless mic system. Regardless, this is something you need to discuss with your sales person. I would assume the less expensive wireless system would have a more limited range. You would want a range that would extend at least a little beyond the physical boundaries of your classroom.

3. Mic Quality
The quality of the actual microphone can also vary significantly. Sometimes, but not always, an inexpensive microphone may make you sound as if you are speaking into a tin can or a large empty building. The higher the quality of the mic, the richer and more natural the tone of the audio. For example, the bass response will be greater and more natural.

Sometimes this is really noticeable, but not always. The best way to test this is have the store sales person plug it up, and let you hear the sound the wireless mic captures before you purchase it. We're basically talking about the frequency response of the mic. The greater the range of response, the more natural the sound.

4. Mic Type
You can purchase at least three types of wireless mics. I'm listing them in order of what is typically the less expensive to the more expensive: hand held, lavaliere, over the ear. The problem with the hand held is rather obvious. You will have a more challenging time writing on the board or using the computer keyboard while holding a hand held mic. The problem with the lavaliere or over the ear microphone is less obvious. You may forget you have it on when you step just outside of the classroom and have a private conversation you are recording or broadcasting into the classroom. Then there is the nearby bathroom... You must remember to mute or turn off the mic.

5. Diversity Reception
The better and more expensive wireless mic receivers (the unit that attaches to the computer/sound system/video camera to receive the signal from the mic you are wearing) will probably have "diversity reception." This means the receiving unit will have two internal receivers for stronger signal reception with less interference, noise, and fewer or no "dead zones." Dead zones are locations in the room or on the stage where the signal just cuts out completely every time you walk into the "dead zone."

Certainly we could go into many more features (go deeper into frequencies and channels, polarity, signal-to-noise ratio, etc.) that could affect cost, especially on the higher end models, but these are the basics. Now let's look at a few options you could purchase. These are not recommendations, just possibilities to get you started in your exploration of a wireless mic system that will meet your budget and performance requirements. Remember, typically, the less expensive, the greater the performance limitations.

Purchase Options

Memorex VHF Wireless Handheld Microphone - MKA381
• Available from Target.com (product link) or your local Target store for around $20 as of this writing
• This microphone is in the toy department for karaoke. But, I was so shocked to find a $20 wireless mic, I bought one to see if it would work at all. It did--with limitations. You will have to determine if it would meet your classroom needs.

• Additionally, you can find any number of other handheld and lavaliere wireless mic system options from Target.com at this link. They are all cost more than $20.

Wireless Lapel Microphone System
• Available from RadioShack.com (product link) for about $50 as of this writing.

• Additionally, you can sift through this link at RadioShack to find other handheld and lavaliere wireless mic system options that are more expensive. This link also includes bluetooth devices, which, while they have special considerations (see end of post), can be used as well!

Audio-Technica 88w
• Available at B&H Photo and Video (product link) for $169.95 as of this writing. We used this mic at Mabry when recording movie projects. It is rather durable, has 2 selectable frequencies, has an omni directional lavaliere mic*, and can be monitored through a head phone jack.

Telex Wireless Microphone Systems
• Available at B&H Photo and Video (product link). These are more expensive, higher end wireless microphone systems that range from $559 to $789 depending on the mic(s) you select. (You would definitely want to lock this up at night!) This Telex system has over 1,100 frequency/channel combinations using UHF (better) instead of VHF, diversity reception, all three mic types are available, and ClearScan technology that tells you which of all of its channel options is receiving the least level of signal interference.

One More Special Option: Bluetooth

Now, this is totally different, but... Don't forget the bluetooth headset you use with your cell phone! It too can usually connect to your computer, if your computer supports bluetooth devices. The Macs running OS 10.5 (and perhaps earlier versions?) all do.

You will have to pair your bluetooth headset to your computer. I don't think your headset can be actively paired to two devices (your computer and your cell phone, for example) at the very same time. You would have to switch from one to the other. I have my bluetooth headset paired to my iPhone, car, and computer. But I can only use it with one device at a time.

Additionally, bluetooth devices typically have a significantly more limited range than the wireless microphones mentioned above. However, if your computer is close enough to your interactive whiteboard, it may well serve your needs to create podcasts of your activity on the whiteboard! I find my headset drops the connection to my computer when I am about 50 feet away from my computer, but I think this is unusually far for most headsets in most situations. If I return within range of the computer in a reasonable amount of time, my headset, the Jawbone, automatically reconnects to the computer. If I remain out of range too long, it shuts off to conserve battery life.

Another consideration with bluetooth headsets is audio quality. The better wireless microphone options will probably sound better than your bluetooth headset, which will more typically sound "like a phone call." However, if the audio quality of a phone call is acceptable to you for a podcast, this shouldn't be an issue.

Final Considerations

I could mention so many other things, but you need to get on with your day. So, a few final thoughts.

Make sure you have the proper connections for your wireless receiver to properly connect to your computer's audio input jack. Be sure to properly adjust your computer's audio input both for source of input (so it's not on built in mic instead of your new wireless audio input device) and loudness. You don't want to clip your audio so that it distorts and sounds terrible or is so soft it's difficult to hear. Be sure to test record before teaching that lesson of a lifetime! You may also need to mute your computer's audio output, depending on your setup, so you don't get that loud annoying feedback sound.

Stock up on the correct batteries for your wireless device. I would suggest exploring rechargeable batteries as purchasing replacement batteries will quickly become more expensive than investing in some really decent rechargeable batteries and a fast charging device. Then, don't forget to recharge your batteries!

Recording your class instruction has never been so affordable and has never required so little extra effort. Certainly, you could turn these recordings into veritable movie productions of the highest quality, but that would take more time and miss the point. Once you are comfortable with this, you can, with just a few clicks of the mouse, quickly and easily produce podcasts for every period you teach. This effort will, without doubt, bring you and your students the greatest return on the small amount of time you invest!

Finally, be sure to check to see if your school district purchasing department has an affordable wireless microphone system on its bid list. Many do, and this could save you a good bit of money.

Happy podcasting!

*An omni directional mic will pick up sound from around the room, not just the sound spoken directly into the mic. This type of microphone has advantages and disadvantages.

[Be sure to check out Dr. Brovey's comment about a wireless USB mic solution. I had no idea such a thing existed and ordered one today to check it out. Thanks for sharing, Andy!]