Wednesday, December 21, 2005

Podcast Perfecto, Part 2

In Part 1, I gave some tips on what to include in your podcast. In this part, I’ll give you some technical tips and tricks for creating and improving the sound of your podcasts. Again, in no particular order:

  • Consider buying a podcast package. There are a variety of online merchants that are selling packaged systems (usually with software included.) You don’t need to spend a lot of money: Sweetwater has a complete podcasting package from M-Audio for $150. Musician’s Friend (owned by Guitar Center) has a variety of packages from $100 to $280. BSW’s podcast packages run from $169 to $1,699. Make sure that the software in the package is compatible with your PC; some packages are only available for Windows or Mac.

  • Get the right microphone. Buying a mic is very confusing, even for experienced users. There are many brands at prices from under $100 to over $5,000. You don’t have to spend a lot for a mic, but make sure that you get one that’s optimized for voice and narration. Mics have pickup patterns that determine from where they can hear sounds. Get a mic with a cardioid or hypercardioid pickup pattern: Cardioid means “heart-shaped,” and this kind of pattern rejects sound to the rear of the microphone. Hypercardioid mics are even more focused on the front and reject sound from the sides and rear.

    There are several technologies that microphones use to capture sound; I’ll discuss the two most common ones. Dynamic microphones don’t require their own power. They’re most commonly used for vocals and musical instruments. They’re rugged and can take a fair amount of abuse. Condenser microphones are more sensitive to quieter sounds than are dynamic mics, and they tend to sound better (although some dynamic mics are equal to or superior than condensers in the same price range.) Condensers require a power supply, which on most models is an external +48 volt supply (called “phantom power.”) Some condensers can be powered by a battery for those times when external power is not available. Condensers are much more fragile than dynamic mics.

    For podcasts, a good dynamic microphone is fine. Dynamic mics don’t pick up soft sounds as well as condensers, but that can be a benefit for podcasts, where a condenser might pick up noise from your computer more easily than a dynamic mic. If you get a condenser, get a large diaphragm model; they’re more sensitive and tend to reproduce sounds more accurately than small diaphragm mics.

  • Buy a pop filter for your microphone. A pop can occur when you say a word like “pizza” or “pack.”  The “p” in these words is called a plosive, and it can momentarily overload a microphone. A pop filter is a small nylon screen that’s placed in front of the microphone to dissipate the energy of plosives. The result is that the microphone hears a “p” but doesn’t overload.

  • Get a good computer audio interface. There are lots of these, and they can be very inexpensive. Some install in your computer (from E-Mu and other companies,) some are dedicated interfaces (from Digidesign, Focusrite, Lexicon, Mackie, M-Audio, etc.,) and some are audio mixers that include a computer interface (Alesis, Digidesign, Mackie, M-Audio, etc.) PC audio systems built into the motherboard tend to pick up electrical noise from other components, so you’re better off to use a separate external interface. Some of the less expensive interfaces don’t have phantom power for condenser microphones, so be sure to check before you buy.

  • Consider getting a headset. Headsets combine headphones with a microphone. Broadcast-grade headsets have high-quality microphones, and you can move around without going out of range of your mic. They’re also less sensitive to noise. Most broadcast-quality headsets are shipped without connectors, so unless you’re good with a soldering iron, buy a headset that already comes with connectors for the microphone and headphones. Whatever you do, don’t use a conventional computer headset. The microphone quality is generally poor.

  • Good audio editing software is essential. There are lots of choices, from Audacity, a free editor that runs on Mac, Windows and Linux, to for-fee software such as Adobe Audition, Digidesign Pro Tools, Mackie Traktion, Steinberg Cubase and Sony Sound Forge. They all work well and, if you know what you’re doing, can be used for creating superb podcasts. All of these products come with filters and plug-ins for adjusting the sound of your recording, reducing noise, etc. Take the time to play with whatever package you select before you record your first podcast. A little training time at the start will pay big dividends later on.

  • Save your podcast as a MP3. All podcasts have to be sent to listeners in a compressed audio format in order to shorten download time and save hard disk space. Every podcast player that I know of supports MP3 files, and every audio editing package can easily create them. AAC, Apple’s standard audio format, is also often used, but not all players can handle it, so unless you specifically want to tailor your podcast to the Apple audience, use MP3.The compression bitrate that you use is critical in determining the sound quality of your podcast. A podcast that’s been compressed too much can sound like a bad telephone call. The good news is that voice can be compressed much more than music. Typical bitrates run from 48Khz to 128Khz. The lower the bitrate, the smaller the file. My suggestion is to experiment until you find the lowest bitrate that doesn’t sacrifice your audio quality. If you’re not sure, err on the side of using a higher bitrate.

  • Learn microphone technique. Using a microphone is a skill that’s easy to learn and is essential for a good-sounding podcast. Use your normal speaking voice, as if you’re having a conversation. Stay close to the mic (two to four inches is usually best,) and speak directly into it, not from the top or sides. If you’re recording directly into an audio editing program, watch the sound meters and keep the volume of your voice below 0 dB (the red zone on the meters) and well above the bottom of the meter. If you’re too loud, you’ll cause distortion, or clipping. If you speak too softly, you’ll have to amplify your voice in the audio editor. Any noise in the original recording will be amplified along with your voice.
Those tips should get you started. Good luck!
Post a Comment