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Ongoing Innovation: Advances In The Art & Science Of Microphones
New technology for better capturing the acoustic sounds of voices and instruments...
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Polar Pattern Control
Continuing with the KSM9, Shure recently released a version called the KSM9HS, featuring switchable hypercardioid and the rarely used subcardioid patterns.

Both KSM9 variations use a dual-diaphragm design, which in general provides greater polar pattern control at lower frequencies than a single-diaphragm design. This technology attenuates these lower frequencies at the rear so the mic is less likely to pick up audio from behind and can be less prone to feedback.

From my tests with this mic a few months ago, the subcardioid pattern resembles an omni that is attenuated at the rear, with a wide frontal pickup having similar level and frequency response, yet being resistant to feedback. The audio quality of both patterns is almost the same, with the hypercardioid setting exhibiting moderate proximity effect when used closely.

Electro-Voice has moved its proven Variable-D technology, which minimizes proximity effect when using a directional mic at close distances, into the RE320 dynamic vocal and instrument microphone. It’s especially useful when close-miking instruments with lower fundamentals such as acoustic bass or larger brass instruments, or to preserve the tonal quality and apparent level of a singer or speaker when they’re continually moving closer and farther from the mic. (The RE320 is the latest generation of the RE20 and RE27 designs.)

Shure KSM9HS offers a selection of polar patterns.

Miniature capsules and directional control aren’t an obvious pairing, yet both Countryman and DPA have made significant advances. With the new H6 headset, Countryman offers omni, cardioid, and hypercardioid patterns, enhanced with a set of acoustic “caps” that enclose the mic element.

The directional elements themselves use a “micro-drilling technique normally used to create cooling holes in jet turbine blades,” with precisely tailored arrays of holes that are smaller than a hair – with each capsule tested and adjusted for maximum null depth and consistent frequency response. The caps allow the user to select a polar pattern that is best for a given application, and go to another one at a different time. Other caps vary the high-frequency response from flat to enhanced.

In the 4099 series of instrument mics, DPA maintains directionality with the use of acoustic interference tubes integrated into the assembly. A precise balance of tube length, materials, and porting allow directional sound to enter the mic without interference, while off-axis pressure waves are acoustically canceled within the tube with minimal coloration.

This effective technology has been enhanced over the past decade, and is also used in the 4080 cardioid and 4081 supercardioid miniature instrument mics and the 5100 surround sound mic. The result is a smooth and accurate directional capture of the audio source.

Miniaturization
Tiny mics with transparent full-range performance extend the ability to unobtrusively place a mic on an instrument, vocalist, or actor/presenter in a live setting, and achieve sound quality akin to using studio-type models.

Audio-Technica BP894 with capsule within a rotating housing on the boom.

Audio-Technica has recently released the BP894 headset, with a miniature cardioid element. The capsule is contained within a small rotating housing at the end of the mic boom, allowing the active side to be precisely positioned toward the corner of the mouth. Different than most headsets where the capsule comes right off the side of the boom, A-T placed it at a right angle to the boom so that it has a T-shaped profile.

Countryman has pioneered miniaturization in headset applications. The H6 is offered at three sensitivity levels, to accommodate applications ranging from normal speaking to high-level operatic vocals. DPA also focuses on these applications, producing mics that are widely used on acoustic instruments, pianos, and more.

Proprietary pre-polarized backplate technology yields a combination of high sensitivity and extreme SPL handling. Both companies provide a wide variety of adapters for different applications and instruments, ranging from violin to woodwinds to acoustic guitars.

Countryman H6 with rugged cables and acoustic “caps” for the mic element.

Miniaturization means thin cables and tiny connectors, which must be extremely durable, as well as water-resistant and immune from RF and EMI interference. According to Chris Countryman, the H6 uses para-aramid fibers (in the Kevlar family) to “more than double the pull strength” of the mic’s cables, along with specialized polymers for the inner insulator and outer jacket to maximize puncture resistance while minimizing induced mechanical noise.

He adds that water resistance is a big focus, with combined custom connectors based on aerospace designs with housings made with medical-industry plastics and hydrophobic coatings helping to achieve an IP67 water and dust protection rating.


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