A Tale of Two Minidisc Recorders

by Frank Beacham

Over the past year radio journalists have discovered Minidisc. Sony's portable magneto-optical format, originally designed to replace the consumer audio cassette, is catching on because it's clearly superior to tape for news and documentary recording in the field.

Sony's 14-ounce MZ-B3 Minidisc portable has emerged as the recorder of choice for radio journalists. Not only is it "bullet-proof" reliable and very compact, but it's the only portable MD model available with built-in microphone and speaker. Put that together with its non-linear, random-access search capabilities and the B3 adds up to an audio journalists' dream machine.

Yet, the B3 is not perfect. It could use a line level output and sturdier connectors. One wonders when Sony is going to abandon that flimsy mini-jack on these high-end portables and replace it with a more rugged miniature connector.

Then there's the issue of AGC (automatic gain control). It's fine for most voice recording applications in the field, but there are times when it can cause problems. The inability to turn off AGC on the B3 can be troublesome when using the recorder for interviews with two microphones.

First, a little background. As is available on many audio recorders, Sony includes a feature on all their MD portables called "Plug In Power," a phantom power system for consumer mics. What Sony doesn't tell you is the 2.71 volts delivered at this connector can power a pair of professional quality lavaliere condenser microphones as well.

With a custom wiring configuration that sends one mic's output to the left channel and the second mic to the right channel, I use a pair of Millimics to record two-person interviews. I picked these tiny condensers, manufactured by Professional Sound Corp. in LA, because they require only 0.9 volts each to operate and can be powered directly off the recorder's mic connector.

I use a special Y-cable adapter so I can route a mic to each channel with full recorder powering. The male mic cable connectors are wired so that if I chose to use only one mic, it can be plugged directly into the recorder and will deliver sound to both channels.

This little rig was created to ease post production. By isolating the output of each mic to a separate channel in a two-person interview, editing becomes much easier. Being able to select either channel is especially useful when one of the speakers steps on the other's words.

However, the AGC on the B3 introduces a potential problem with such a set-up. Because the recorder rides gain on both channels in simultaneous lock-step, it forces the gain up on the mic that's not being used at any given moment. Here lies the trouble.

Not only does this increase noise and sometimes cause unwanted pumping effects, I found instances where an artifact resembling phase cancellation occurred. Though no definitive tests have been conducted to determine exactly what is happening, a good guess is there's a bleed-through occurring somewhere in the signal path that's allowing the AGC to create phase cancellation between the two microphones. At least that's the way it sounds.

I was able, however, to end run the unwanted effects of AGC with Sony's portable MZ-R30 Minidisc recorder (now with a new lower list price of $449.00). The R30, introduced earlier this year, has no built-in mic or speakers, but it has the ability to manually set recording levels without automatic gain. When in the manual mode, recording with our two microphone set-up was artifact free and quieter than with the B3.

Though the R30 is designed primarily for music recording and lacks some of the built-in conveniences of the B3, it should be seriously considered by audio professionals seeking the convenience of MD field recording. The manual level record feature alone makes it a perfect companion to the B3 when doing interviews on separate channels.

There is, however, a quirk with the R30's manual record function. The mic level must be adjusted when the recorder is in the standby mode. You cannot ride levels while the recording is actually taking place. This is not as ominous as it might sound at first. I found the R30 to have a lot of headroom and this function is not a major inconvenience in most recording situations.

Because Sony's target market for the R30 does not include audio professionals, some of the recorder's features are a bit buried beneath the surface. Example: Though the R30 has both mono and manual record capability, the instruction booklet provided with the recorder does not tell you how to use both at the same time.

Sony's U.S. marketing staff had to go to Tokyo to get the answer. First, follow the normal instructions to put the R30 in the manual level mode, then press the "mode" switch and wait until the words "Mono Record" appear and then disappear on the LCD. Now you can set levels. Once set, hit the "pause" button to begin manual level, mono recording.

Sony's MZ-B3 and MZ-R30 are both excellent field recorders for audio journalists. The trick is to understand which recorder does what best and use it accordingly. One day, hopefully, Sony will acknowledge that their MD portables are being used by professionals. Then they might muster their extraordinary engineering skills to combine the best attributes of both models into a single, compact, pro-level MD recorder truly optimized for audio journalism.

(Frank Beacham is a New York-based writer and producer.
Visit his web site at: http://www.beacham.com.
Mail: 163 Amsterdam Ave.#361
New York,NY 10023.
Email: [email protected])

C1997 by Frank Beacham

Return to the MiniDisc Community Page.