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Review: Audio-Technica BP40 Large Diaphragm Dynamic (LDD) Broadcast Microphone

Designed for use as a broadcast vocal microphone, the BP40 is actually quite superb in a broad range of applications where a large diaphragm dynamic (LDD) transducer with a hypercardioid polar pattern can be useful

Designed for use as a broadcast vocal microphone, the BP40 is actually quite superb in a broad range of applications where a large diaphragm dynamic (LDD) transducer with a hypercardioid polar pattern can be useful. In both performance and aesthetics, it resides somewhere between a classic broadcast microphone—like Electro-Voice’s venerable RE20—a workhorse large diaphragm dynamic, and, in some ways, the variety of dedicated large drum/kick drum microphones currently available in the marketplace. That said, it’s truly unique in its sonic signature and will be a great choice for discriminating professionals for a variety of good reasons.

In both performance and aesthetics, the BP40 resides somewhere between a classic broadcast microphone—think Electro-Voice’s venerable RE20.

The BP40 features a 1.5-inch diaphragm with A-T’s patented floating edge design; while there is no firm pro-audio industry rule on what makes a dynamic microphone a “large diaphragm” one, I and my contributing colleagues to Pro Audio Review generally consider any diaphragm with a diameter greater than one inch “large,” which definitely places the BP40 in the LDD camp. The BP40 provides a 100 Hz high-pass filter (HPF) switch, rolling off frequencies between 50-100 Hz; its response tops out at 16 kHz. Marketed as a broadcast microphone, the BP40 includes a humbucking coil to prevent electromagnetic interference (EMI), which can be valuable in applications beyond traditional broadcasting, too.

Included in the BP40 package is the simple-but-effective AT8483 mounting clamp; an AT8484 shock mount is available at extra cost. For my needs, the AT8483 worked well enough, even with the BP40 placed in tight areas such as through a bass drum’s ported front head. So, yes—the BP40 also handles high SPL, or at least handled everything I threw at it with no audible distortion.

In my own applications on vocals of all types—sung and spoken word, male and female with varying ranges and styles—I found the BP40 to be notably articulate and attractively full. It is not boomy (unless the source is) or overly sculpted (like some drum-centric LDD microphones can be), while its vocal range-friendly frequency “emphasis” is significant yet classy.

The BP40’s sonic signature is centered on its slow-rising presence peak—from 1 kHz, it climbs to +10 dB at 4 kHz before touching down (momentarily) to 0 dB at 5 kHz. With its unique frequency response, the BP40 is certainly its own thing. The BP40’s multistage proprietary windscreen is a notably great pop filter. In application, I A/B’d it alongside some of my favorite vocal microphones—both dynamic and condenser in type—and it was arguably superior at controlling troublesome ‘p’ and ‘s’ sounds while recording, sounding deep, rich and detailed throughout.

The BP40 features a 1.5-inch diaphragm, definitely placing the BP40 in the “large diameter dynamic” camp.

I recorded the BP40 alongside some LDDs I’ve used on and off for years, including the aforementioned Electro-Voice RE20 and Heil Sound’s PR30 and PR40, plus the ubiquitous AKG D112, where applicable. These informal shootouts included vocal, electric and electric bass guitar cabinets, and kick drum applications. Size-wise, the BP40 is closest to the RE20 yet slightly shorter and only-slightly lighter. Noteworthy, the BP40 was the only hypercardioid of the lot (all others were cardioid), effectively making it the “most sonically focused” in blind A/B comparison. Also, I believe its frequency range and response signature add to its intimate sound on vocals and, for example, its immediacy on guitar cabs.

The BP40 on kick drum truly surprised me. I clearly preferred it on all three drums I placed it in front of and/or within: a mid ’60s Ludwig 22-inch, a late ’70s Ludwig Super Classic full-maple 22-inch and an early ’90s Mapex full birch 22-inch. My best guess is that the BP40’s “open” sonic characteristics, un-hyped bottom end and hypercardioid-enabled focus gave me the closest approximation of the drums upon playback, but with some emphasized frequency definition around the “beater-meets-head” ballpark. Further, I found the 100 Hz HPF most always useful, cutting unnecessary flab down low.

At the risk of sounding cliché, I believe the BP40 could be a future classic, destined to serve many broadcasters and recording masters alike who give it a try. It’s affordable enough for self-recordists as well as most live venues, houses-of-worship and other budget-conscious facilities. For those needing a focused, high SPL-handling LDD that sounds natural yet immediate and significantly detailed—one that’s equally at home on vocal, drum and various applications in between—the BP40 should serve them well.