There are lots of reasons why you might want to podcast your lectures. You might be teaching an online class or providing supplementary lecture material for students in one of your regular (face-to-face) classes. Or, even better, maybe you are embracing the open courseware movement, and making your course material available to people both inside and outside of your university – regardless of whether they are actually enrolled in the class.
Now, to be clear, I’m using the term “podcasting” generically – meaning (in this context) the online distribution of recorded lecture material. The platform on which the audio file is listened could be an iPod (or another portable MP3 player or mobile internet device), but it could also be via the browser’s built in audio player, or a desktop audio player such as iTunes or Songbird (an open source alternative to iTunes – and one of my favorite apps)
I’m going to break this topic into a series of three posts – on on each step in the process: recording, editing, and distributing. so, first up – recording.
Before we get started, a couple of caveats. First off, I’m by no means an audio expert. I’ve learned through experimentation, trial and error, and well placed emails to friends and colleagues who are far more up on the art & science of audio than I am (which, frankly, is that difficult). Second, this isn’t an exhaustive technical step-by-step – its more of a “here are some things you need to think about, go out and dig deeper or experiment for yourself” kind of approach.
When it comes to recording, its all about planning and equipment. When it comes to equipment, you need to think about three things: the mic, the recording device, and the recording software.
You’ve got a bunch of options in this regard. First, you could go with a portable digital recorder. These are all-in-one portable devices – complete with an onboard mic, storage, and the ability to set a wide variety of recording options (audio quality, etc.). They are handy because, as the name suggests, they are portable. You can stick them on a nearby desk or the lecture podium, hit record, and go to town. When you are finished, you can simply dump the audio file that was captured (usually via USB) onto your computer for editing. There are, however, some drawbacks to portable digital recorders. First, the mics or portable digital recorders are nowhere near as good as standalone mics. This means that the audio quality might not be so good. Second, portable digital recorders can get pricey – anywhere from $100 to $600. When it comes to portable digital recorders, you need to consider storage as well. Most of them have a small amount of onboard storage. However, if you are planning on recording for any significant length of time, you’ll need to get a storage card. Most portable recorders have an SD or mini SD slot. I would suggest going for a 2GB card at the very least. The higher the quality of the audio (something which you can set on the recorder itself) the more space it will take up. So, if you want to record at a very high quality, you’ll need to factor that into the storage card choice you make.
Your second option is to go with the portable digital recorder, but add an external mic. The benefit to this is that the audio quality is going to be a lot higher. An external mic is also going to pick up a wider range of sounds – which is good if you want student comments/questions/discussion included in the recording or if you have a tendency to wander around a lot (like I do). The down side to this is that an external mic means an extra thing to carry – which is a pain given the fact that may of us have bags that are already full to bursting. The other issue is external mics can start to be really expensive. Expect to pay at least $200 – probably more. I don’t presume to understand the technical ins and outs of microphones – and there are lot of them. My suggestion when it comes to choosing a mic is read reviews online (with an eye towards your specific requirements) and talk to colleagues or IT people around campus for their recommendations. The mic you choose is going to have the biggest impact on the quality of the recorded audio. Cheaper mics are going to result in lower quality audio, while more expensive mics (and they can get really expensive) are going to give you better audio quality.
Another option is to let your laptop fill the role of the portable audio recorder. All you do is run a mic directly into your laptop, fire up your favorite audio software (more on that in a bit), and hit record. This is a pretty attractive option as it means you don’t have to plunk down extra money on a portable audio recorder. Its also a good way to do things as, compared to an an SD or mini-SD card, our laptops have limitless storage. This option also saves you a step – you don’t have to dump the audio from the external recorder onto your machine for editing, because its already on your machine. There are, however, a few downsides to this approach. First off, the laptop/mic setup is a little less portable than just a portable audio recorder. Second, and this is the big one, you are going to have to make some compromises with the mic. There isn’t anywhere near the range of USB mics available. You can definitely go cheap (there are a lot of cheap options out there). But cheap means lower sound quality. If you want to get a USB mic that will give you better quality, you have less options. The Snowball from Blue Microphones (http://www.bluemic.com/snowball/) is one of the most popular choices. It goes for just under $100 and its got a pretty impressive range of features. I’ve had direct experience with the Snowball, and I wasn’t very happy with it. The quality was decent, but it had a very soft signal level – which basically means that all of your audio comes out with a very low volume. The second problem I had was the stand that comes with the Snowball worked very poorly (the word I would would to describe it is “janky”) – it was pretty much broken straight out of the box. I’m not sure if that is a universal problem, or just a problem with the unit I got. The result is that my Snowball has been sitting in my office – relatively unused – for quite awhile now.
If you can’t find a good quality USB mic, but still want to use your computer as the recording device, you’ve got another option. You can buy yourself an audio interface with a mic in and a USB out. Basically, an audio interface is square little device in which you plug your good quality, non-USB mic. Then, you plug the USB out to your computer – and, voila! A good quality, non-USB mic working with your computer as the recording device. The downside to this is that its another piece of gear that you’ve got to carry. Its also another piece of gear you have to buy. An audio interface can range from $80 to $400 (and much more for professional models). The more expensive the unit, the more features you get. However, for the needs of a professor recording their lectures, you can definitely go on the cheaper end of things. One of the nice fringe benefits of an audio interface is that many of them can can work with multiple mics. That way, you could have one mic near you, and one mic closer to your students – thereby allowing you to capture more of what’s going on in the room.
The third part of the “laptop as recording device” equation is the actual software you use to do the recording (if you are using a portable digital recorder, this isn’t a concern as the software is part of the device itself). Honestly, any audio editing software will do. Most computers have some sort of built in app that will do the trick. If you want to go free and open source (and cross platform), check out Audacity (http://audacity.sourceforge.net/). If you are using a Mac, Garage Band (which comes free with with the OS) works just fine. All you need to do is fire up your audio recording software, make sure the source is set to your external mic, and you are good to go. Do some audio checks (“test, test, check, check…check one, two” that sort of thing) to make sure your levels are good. One of the sure fire ways to have crappy audio quality is to have your levels set too high. When you are finished, always save your audio file to a specific place on your hard drive (we’ll cover compression and export in a later column). I also back up all of the raw audio files on an external drive – just in case.
The last piece of the puzzle has to do with a bit of strategy – specifically mic placement (which I’ve already alluded to slightly). If you are working with a stationary mic, and you walk around a lot, you are going to get audio that has an inconsistent volume. The only real way to deal with this is to place the mic in an optimal location, and restrict your wanderings. Also, you should consider placing the mic in a location that can pick up both your voice, as well as that of your students. I’ve already mentioned that many audio interfaces will accept more than one mic in – which is good if you want a more sophisticated mic setup.
So, what is my setup? I use an portable audio recorder (specifically, a Samson Zoom H4) with a 2GB SD card. For a mic, I’ve completely sidestepped the whole stationary mic-wandering professor conundrum by using a wireless lapel mic (I use the Sennheiser freePORT Presentation Set). The wireless mic speaks to a receiver which is hooked up to the portable audio recorder. I love this setup, and it has served me very well. It a allows me to wander around to my heart’s content and still get good audio quality. The downside to this setup is that it doesn’t come cheap. The portable audio recorder I use goes for about $250 and the wireless mic setup goes for about $350. This means that my setup is about $600 worth of equipment – which is probably more than most are willing to spend.
Next time around, we’ll talk about what you need to do after you’ve actually recorded the audio – editing. In the meantime, feel free to share your recording tips and tricks, as well as the equipment that you use.