Information for a Visual Age

Professional quality audio for $350

In Technology on December 16, 2009 at 11:00 am

A few months ago I put together a package of audio equipment for recording our live events at the office. The problem was that we were previously letting our great events go unrecorded, meaning those who couldn’t make it would miss out on our great programming. In addition, when the conference room really filled up, the audience sometimes had difficulty in hearing more soft-spoken presenters.  So we needed both sound recording and sound reinforcement. And we needed it on a budget, because we are a nonprofit with a modest budget.

Early Recordings

So here’s what we did. At first, we purchased an Olympus DS-30 digital voice recorder (~$100). The Olympus has a great microphone in it with a bunch of different recording settings. We chose the high quality (HQ) mono — we didn’t need stereo for what were going to be voice recordings. (I just learned that the Olympus can be programmed to turn on and start recording at preset times. Very handy, and I’ll show you why in a subsequent post.)

Eliminating Distractions with Directional Microphones

We used the recorder as-is very successfully for about a year. But the Olympus has an omnidirectional microphone, meaning it would pick up sound from anywhere in the room. That means lot’s of distracting noises were picked up — coughing, paper rustling, doors shutting, etc. So we upgraded to some directional microphones, which accept sound only from one direction. When they are pointed at a presenter, they pick up his or her voice well but they reject sound that comes from “off axis” (meaning sound from the side or behind a microphone).

We chose Shure 81A microphones, for about $100 each. They were connected to a Behringer xxx mixer, about $80, which provides the phantom power to the microphones and let’s us record more than one guest at a time. The Behringer mixer can handle up to 2 mics at a time, though the company also offers models that handle more. The microphones were plugged into the mixer, with the output from teh mixer then plugged into the microphone input on the Olympus recorder (notice we are still using the Olympus to record, but we are using an external microphone rather than teh Olympus’s built-in mic).

The difference in the sound recording was immediately apparent. Not only were distracting coughs significantly reduced, but the sound quality of the presenters’ voices was richer and deeper. The sound felt much more human, while the previous sound felt tinny and far away.

The Setup

The setup for the whole system is surprisingly simple. The mics are placed on the table, and they are connected to the mixer inputs with XLR cable. We purchased a cheap cable floor cover to run the cable over the carpet. The outputs on the mixer go to

  1. The amplifier for our ceiling speakers
  2. The Olympus recorder

The mixer has a separate volume knob for the speakers (labeled “main mix”) and the recorder (“control room”). This works to get the output level right for both the loudspeakers and the recorder.

After Recording — Post Processing

Recording is only the first part; the second part of voice production is post-procesing, where we make the audio sound as good as possible.

For post-processing the sound, I used the free, open-source program Audacity to edit my sound files. Audacity is very capable and can export to MP3 (with the addition of the LAME library). The Olympus recorder only records in Windows Media Audio (WMA) format, but with the beta version of Audacity 1.3.x, you can open WMA files with the optional FFMpeg decoder.

Once the audio is imported into Audacity, I cut out some from the beginning and end, and added a prerecorded track (about 30 seconds long) at the beginning with a little music and a voice saying “This is a recording of the East-West Center in Washington. Copyright 2009.” This track is the same on every file. By having the same intro to each file, brand consistency is established, similar to the opening track of a TV program or radio show.

So the post-processing process from beginning to end is:

  1. Record audio using Olympus recorder
  2. Plug Olympus into computer and download audio file to computer
  3. Open the file in Audacity
  4. Make adjustments to audio, including raising the volume if needed
  5. Add title audio track
  6. Export from Audacity to MP3 format (using 32kps mono)
  7. Upload MP3 file to web server

Conclusion

If you’re just recording from your computer desktop, I would suggest a nice large-diaphragm microphone with a USB connection. That will allow you to get great sound quality without the hassle of needing a mixer. One model is:

Hopefully this helps someone put together some really professional sound recordings of live events for relatively little money.

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  1. Cool to hear about your setup – and you’re right in line with all the linguists using Audacity for editing/export to MP3! It’s a great program.

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