Most podcasts are produced from the podcaster's home or office, so lets talks about the tools required for a basic podcasting studio. Some folks grab interviews on the go, so a section of this post is dedicated to portable recording. Many podcasts include remote guests who call in on either a traditional phone line or an online phone service such as Skype, so telephone tools are covered in detail.
In any recording situation, the environment is important to the final quality, so this covers things you can do to improve your recording environment. Finally, some suggested combinations of equipment are listed, so that you can make a shopping list for your audio gear.
Using Basic Production Tools
Many multimedia computers ship with microphones, speakers, and soundcards, but in general the quality of these bundled tools is not very high. That doesn't mean that you can't produce a podcast with whatever tools you have on hand. But if you want to produce to a high standard, you should invest accordingly. Your podcast quality is limited by the quality of your audio signal chain, and that starts with your microphone.
Microphones
The quality of your podcast, to a large extent, is dependent on the quality of your microphone. If you use a cheap plastic mic, your podcast sounds cheap and, well, plastic. Spend a hundred bucks, and you can compete with the best of them. But before you pull out your credit card, learn a little bit about how microphones work and which type of microphone is best for you.
Pickup patterns
Microphones have different pickup patterns, or directional response. Omnidirectional mics pick up sound from all directions equally. Directional mics pick up sound predominantly from a particular direction, and reject sound from other directions. Most mics are directional, with a particular pickup pattern. These are the most common pickup patterns:
Cardioid: Cardioid mics pick up predominantly what is in front of them, less of what is to the sides, and very little of what is behind them. The name derives from the heartshaped pickup pattern.
Supercardioid (or hypercardioid): These microphones exhibit an exaggerated cardioid pattern, with more rejection of sound from the sides and rear. Hypercardioid mics are commonly referred to as shotgun mics.
Figure 8 (bi-directional): Figure 8 mics pick up sound from the front and rear, but not from the sides.
As you can see in figure above, mics have different pickup patterns, and more importantly, have a front and a back! It's pretty obvious which end you speak into with handheld mics, but it may not be so obvious with some higher-quality mics. For example, some mics have a switch to determine the pickup pattern. If you switch from a figure-8 to a cardioid, which side is the correct side to speak into? In most cases, the manufacturers put their logo on the "front" of the mic. If you're not sure, you can always try speaking into both sides of the mic. When it's set to cardioid, one side sounds much louder and brighter than the other side.
In most cases, a directional mic with some type of cardioid pickup pattern is the best choice. These mics can easily be pointed at the talent, and by design won't pick up much else. The one exception is with clip-on (or lavalier) mics. If you decide that clip-on mics are going to work best for your needs, you should buy omni versions. Even though they're omnidirectional, they really don't pick up anything other than who they're attached to. The advantage of the omnidirectinal pickup pattern is apparent when the person turns his head from side to side. With directional mics, this leads to a dramatic drop off in signal level. With an omnidirectional mic, the drop off is far less apparent.
Dynamic versus condenser mics
Most microphones fall into two basic categories, dynamic microphones and condenser microphones. Dynamic microphones have a diaphragm that is attached to a coil of wire, known as the voice coil. The voice coil is suspended between magnets. When the diaphragm vibrates in response to incoming sound, the magnets create a very small oscillating current in the voice coil by a process known as electromagnetic induction. This current is an electrical representation of the sound wave.
The diaphragms in condenser microphones consist of two plates coated with a conductive material such as gold. A voltage, known as phantom power, is placed across the plates to form a capacitor. (Historically, capacitors were called condensers, hence the name condenser mic.) When incoming sound causes the plates to vibrate, the distance between them varies, which varies the capacitance. This variation in capacitance is converted into an oscillating current, which is an electrical representation of the sound wave.
Condenser mics are much more sensitive than dynamic mics. This translates to higher frequency response and lower noise. However, the sensitivity comes at a price: Condenser mics are very sensitive to handling noise, and therefore cannot be held in your hand. They're always placed in microphone stands and sometimes in special suspension mounts. If you're in a controlled situation, you may want to take advantage of the higher quality that condenser mics offer. Some reasonably priced condenser mics are shown in Figure 2.
Dynamic mics may not have quite the frequency response and dynamic range that condenser mics have, but that doesn't mean there aren't some fabulous dynamic mics. In fact, two dynamic mics are broadcast industry standards, the ElectroVoice RE20 and the Shure SM7B, shown in Figure 3. These mics are prized for their tone, and both are incredibly resistant to the proximity effect. Either of these would be ideal for your podcasting studio.
If you're going to be working on location or outdoors, or you just don't want to be tied down to a chair in front of an expensive mic, you can buy a nice handheld mic. Handheld mics are dynamic mics by definition, because they must be resistant to handling noise. They're usually sturdy enough to survive being dropped, which, as any reporter can tell you, is important. You should always have a handheld mic or two, because they're very reasonably priced and can serve as backups in case of equipment troubles. Some great handheld mics are shown in Figure 4.
No comments:
Post a Comment