To help ensure you retain an audience you do need to make sure the audio recorded is at the best possible quality. Fortunately you don’t need to spend thousands of pounds on equipment to get listenable quality but it will help to have an appreciation of some of the theory.
The two main items of equipment you’ll need for audio podcasts are some form of microphone and some form of recording device to which the microphones are connected.
Many if not all laptops come equipped with a microphone these days for use with applications such as Skype but unless you have a particularly good laptop these mics will be cheap and nasty affairs and in any event will limit the content of your podcast.
So not only is the quality of the mic important but so are the acoustic properties of the mic as well. As in all things in life there are different types of acoustic “pick up” and you need to have an appreciation of these designs so that you can position the microphones for the best possible placement for effective audio capture.
The basic types of mic acoustic characteristics are illustrated in the following diag:
Omnidirectional, as the name implies, has no selective sensitivity, it will capture sound equally in all directions. At the other extreme are “shotgun” mics that are far less sensitive to audio from either side and much more sensitive to sound from in front. They are very “directional” and are ideal for capturing the sound of a bird singing for example.
The best mics to use for your podcasts are “cardioid” mics. These are somewhat less sensitive to sounds from behind the mic than they are to sounds forwards of the mic; in other words sounds coming from behind the mic will be suppressed by about 25dB, technically known as the “rear projection”.
Now you have to give some thought to the nature of your podcast content as this will determine the physical design of cardioid mic that you will end up buying. For example if your podcasts are entirely studio-based there is no need to use a wireless “tie” mic, a static studio mic will be perfect. On the other hand if you wanted to capture the audio of a speaker at a conference, then a wireless tie mic would be ideal.
For many of the podcasts we produce we use small cardioid “tie” mics that are wired directly to the recording device, whether that’s a digital audio recorder or a broadcast quality video camera. The advantage of this approach is that there is a good “signal to noise” ratio between the speakers’ voices and the surrounding sounds without the risk of “audio drop out” which you sometimes get with wireless mics.
The drawback of wired mic is there are a pair of wires trailing along the floor which may not be acceptable in some situations. For example when we record our Made in Great Britain cooking show where we feature chefs cooking in their kitchens, it would clearly be a risk to have trailing wires so we go wireless with the receiving station mounted on the camera.
We recently provided a podcast recording kit to a customer and as they wanted maximum flexibility for their podcast content, we recommended a pair of wireless tie mics such as these:
Whilst not cheap, these provide excellent sound. The tie mic is wired to a transmitter (a body pack) which transmits the audio to a receiving station which in turn connects to the recoding device by an “XLR” port, the industry standard for professional grade audio equipment.
So what do you connect these mics to? You need a digital recorder of some sort, like a 21st Century tape recorder. I can recommend the Zoom H4N and to fully appreciate what this does we need to go into some theory, which we’ll cover in the next blog.