DPA Microphone’s 4071-BM

Many of the microphone applications require small, non-obtrusive microphones that are highly resistant to moisture, extreme temperature change and humidity.
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The 4071-BM miniature microphone features a fixed microphone grid with a soft pressure boost of typically 5dB at 4kHz to 6kHz.

These days, every time you change the channel, there is a new reality-based show on your television. The production companies producing these programs rely heavily on their microphones to capture each and every sound bite, even in the noisiest and acoustically challenging spaces. Many of the microphone applications require small, non-obtrusive microphones that are highly resistant to moisture, extreme temperature change and humidity. I’ve had the opportunity to review the 4071-BM miniature microphone with presence boost from DPA Microphones, and it survived my tests.

The first challenge for the microphone was in a bowling alley, where a production company was shooting a pilot. The thunderous sound of bowling balls slamming into pins and the bursts of cheers from bowlers and spectators filled the room. Two female bowlers were fitted with microphones placed in the center of their chests just behind their brassieres. Bowler A was fitted with a Sony lavalier microphone, and Bowler B was fitted with the DPA 4071-BM. Both microphones were transmitting signals through a Sony 820 wireless system and being recorded at 48kHz direct to a hard disk Deva digital recorder.

After listening to the recordings, the 4071-BM sounded very natural and not forced. The speech was clear and intelligible, with a peak at about 5kHz, yet still sounded open to the ambient background sounds. The biggest difference between the two microphones was in the low end and overall headroom. Bowler A had a consistent low rumble that made the recording slightly muddy. That microphone also clipped a couple times, resulting in a much smaller dynamic range than that of the 4071-BM. The 4071-BM microphone has a maximum sound pressure level (SPL) of 144dB before clipping, a large range for any body-worn microphone.

The microphone’s second challenge was in a large, open valley at a 73,000-acre park. The head wrangler, Chad Lammers, was fitted with the microphone. The winds were whipping through the valley at high speeds, so you can imagine that the low-end buffeting would be a big problem. With the microphone placed just under Lammers’ collar and fitted with DPA’s Miniature Windjammer DUA0571, the buffeting wind was cut down significantly.

The 4071-BM is an omnidirectional microphone, which inherently cuts down wind and pop noise, keeping the proximity effect on the low side. These characteristics played a big factor in reproducing a clear, intelligible recording. Though there was some evidence of low-wind rumble in the recording, it did not cause any problems later in the mix session. Another helpful feature is the fixed soft boost grid, which gives the microphone a 5dB boost between 4kHz to 6kHz. It is between that frequency range where the presence in a human voice is most apparent. When we were filming Lammers in action, the microphone performed well under such harsh conditions.

The third challenge was at the same park, but this time the scene was inside a teepee during a prayer sequence with Rosalie “Little Thunder.” Rosalie was wearing the microphone directly in the center of her chest under her clothing. The film crew was also using a Schoeps shotgun microphone hooked to a boom pole. The Schoeps microphone would pick up the participants from overhead as they took part in the prayer. Both the Schoeps and 4071-BM microphones were connected to a Shure mixer, where their respected signals were sent to separate channels on the Sony high-definition camera.

With Rosalie’s microphone placement, you would expect a slightly muddy sound due to sound reflections off the chest cavity. However, DPA has a nifty adapter called the DAD6024, which connects directly to the 4071-BM and turns around to a standard XLR male connector. This adapter attenuates the frequency area around 800Hz by 3dB to 4dB. Once we returned to the studio and played back our recording, we were pleasantly surprised with the quality of the 4071-BM and how it blended with the ambient background recorded by the Schoeps microphone.

Whether in the studio during a live performance or out in the field filming the next great show, the DPA 4071-BM microphone, DAD6024 adaptor and DAK4071-F accessory kit for miniature microphones are must-haves for any audio field recordist.

Rob Fritts is senior sound designer/mixer for Henninger Digital Audio.

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