Mar 10, 2008

Using Telephone Tools

Using Telephone Tools
Many podcasts include call-in guests. To get the audio from the phone into your computer, you need a telephone hybrid. Hybrids are specially designed to accomplish this with the least amount of noise possible. This is a little harder than it seems, because telephone lines are often very noisy. Telephone hybrids cost anywhere from $10 to $1,000. The $10 versions available at your local electronics store sound horrible and should be avoided.

Hybrids fall into two basic categories: analog and digital. The analog versions use basic circuitry to extract the audio from the phone line. The digital versions use sophisticated signal processing to clean up the audio signal and separate the caller from the interviewer. If you plan on doing lots of interviews over the phone, you should seriously consider buying a high-quality digital phone hybrid, as expensive as they may be. If phone calls are not a regular feature of your podcast, you can spend a little less, but you should still buy a good-quality hybrid, like the ones shown in Figure 1. If you make your phone calls on a mobile phone, you can buy hybrids that can be inserted between the cell phone and the earpiece.


Figure 1: Telephone hybrids: The JK Audio Inline Patch, Telos One digital hybrid


Skype
A number of technologies have been developed in the last few years that allow telephone calls to be made over the Internet instead of via a Plain Old Telephone System (POTS) line. One of the most popular is Skype. Skype is a P2P telephony system, which means there isn't a huge centralized server that's managing all the resources. It's all decentralized and distributed, and even better, it's free. Many people are taking advantage of this new service to make long-distance calls to friends in foreign countries.

Of course, this is all fine and good, but how can you record your Skype conversation? You can't use the fancy telephone hybrids discussed in the preceding section, because you're not using a phone! Instead, you use specialized software designed to record audio directly from your software audio mixer. A number of applications are designed to do this, with more appearing all the time. Here are a few examples:

Hot Recorder (Windows): This application works with a number of different Internet telephony applications and even includes voicemail for Google Talk and Skype. It records into a proprietary .ELP format but converts this file to .WAV, .OGG, or .MP3.

Pamela Professional (Windows): This application includes a number of features including voicemail and support for "pamcasting" (podcasting).

Audio Hijack (Mac): This application records virtually any sound off your computer. It includes built-in timers for scheduled recording.

Gizmo

Gizmo is another Internet telephony program. It works pretty much the same as Skype, but it has a couple of cool added features. First, it is SIP enabled, which means that you can talk to people on other VoIP networks, not just Gizmo users. It also is integrated with Google Talk, which is another up and coming Internet telephony application. Best of all, Gizmo includes recording functionality. Just push the record button, and presto — instant podcast.

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