Audio-Technica BP40 Large Diameter Dynamic Mic

Audio-Technica BP40 Dynamic Microphone

When I first saw the new Audio-Technica BP40 dynamic mic, I thought, "Hmm, looks like the love child of a Shure SM7 and an Electro-Voice RE20. A little longer than an SM7, but with a grille more like an RE20 or RE27N/D.

Large diaphragm (1.47") , hypercardioid pattern, humbucking coil, 6 dB/octave 100 Hz low frequency cut, integral pop filter, relatively high sensitivity - –48dB (3.9mV) re1V at 1 Pa, 450 Ohm impedance, 50-16,000 Hz frequency response, less than 1.5 pounds.

BP40 Capsule

Got it;
- diaphragm bigger than most LD condenser mics
- tight pattern

Looks like an on-air mic with kick drum possibilities. $349 on the street, which is about $100 less than an RE20.

On-air microphones have to handle close talking announcers, so stopping pops is essential. The BP40 has a 3/4" thick, replaceable foam pop stopper seen in the photo below. I unscrewed the headgrille and shot the below photo aimed back up towards the back of the foam.

Inside the BP40 Headgrille

Having a replaceable foam pop stopper is very useful and healthy, especially in radio stations where a cold can be quickly passed from person to person as they nuzzle the mic and change shifts. The BP40 headgrille simply unscrews, allowing you to change the foam and disinfect the headgrille. The headgrille also serves another purpose, it keeps the talent at least a specific distance from the diaphragm to prevent closer and more proximity effect from overwhelming the almost inch and a half diaphragm.

Radio DJs frequently like to "eat the mic" to take advantage of the bass building proximity effect that getting close to a directional mic produces. Working close also reduces bad room acoustics and noisy HVAC systems. Let's move to video for a comparison between the BP40 and RE27N/D.

In the above video shot in my studio, you can hear that the the pattern is tight as the graph below left indicates. There's a slight tail at 5kHz, but when you listen to the above video, while you might be able to hear it a little more than with the RE27N/D, I don't consider it a problem.

The BP40 has a humbucking coil to reduce the pickup of stray AC fields. I have an "AC Hum Hell Hole" in one spot here in the house. It's really tough on mics. especially ribbons and dynamics. There's a 200 amp AC service cable that runs down the outside of the house to the main panel in the basement. Inside, in my den, some mics begin to pick up the hum as far away as three feet from that wall. I got the BP40 all the way to the wall before I heard the faintest hum.

BP40 Polar Pattern

BP40 Frequency Response

My first career was 17 years in radio as an on-air talent and Production Director. That's a lot of time on mic; a five hour air shift and at least three hours of production, five days a week. Different stations have different mics. Your voice becomes a test tone. You learn a lot about mics. If you're still in radio production and have somehow missed Radio And Production magazine, check it out. Editor Jerry Vigil has been working hard for quite a few years to make RAP an oasis for radio production people.

Depending on the voice and delivery, you learn to use the variable frequency response caused by working the proximity effect of the mic. Above right, the frequency response graph of the BP40 works well for voice; the frequency response graph shows a nice little peak at just below 4 kHz. The 6 dB per octave bass cut shows the roll off begins at 200Hz. Again, in the above video, you can hear the effect. You may well need the Low Cut for big voice performers who like to eat the mic. Not a big voice? Then leave the Low Cut off and move in.

WTMD

WTMD Ops and Tech Manager Donnie Carlo

In order to get a wider scope on what the BP40 sounds like, I reached out to Operations and Technology Manager, Donnie Carlo, at WTMD. Carlo arranged to have me come in to the WTMD studios and also mentioned that one of their female air talent could help me by cutting some tracks. Carlo had an ElectoVoice RE27N/D and a Shure SM7 lined up for me. These are typical on-air mics. Perfect!

WTMD is a college station, attached to Towson University, but it's no ordinary "college radio station." Their programming and listener outreach is the best I've heard and seen. We're very fortunate to have them here in Baltimore. It's a Class B1 FM at 89.7 MHz with a power of 3 kW. Several years ago they received a grant that allowed them to move from the basement of one of the older university buildings to a new facility at 1 Olympic Plaza in Towson, MD. It's a beautiful facility with updated gear. I know many professional radio people who have never worked in a station as sweet as this.

She who will not be named @WTMD

We spent about an hour in Studio C using my voice and the voice of "the female talent who preferred to be unnamed" - how's that for mystery!? We recorded with the Audio-Technica BP40, Shure SM7 and ElectroVoice RE27N/D with the top EQ roll-off. I also recorded my voice back here at my studio using GML preamps and an RME ADI-8 DS A/D converter interface.

I found that, as with the RE20's Variable D design that minimizes proximity, the BP40 proximity effect didn't really kick in on my voice until I was two inches or closer.

Peavey International II kick and BP40

Drums
I had a music session here and used the BP40 on kick drum. I wasn't sure how the ten year old Peavy International II kit would sound. The kick is a 22" x 14", 9-ply basswood drum. (to the right.) I was very pleased by the the entire kit and the kick drum. The extra barrel with yellow label is a Shure A15AS variable pad set to -15 dB. The kick drum track below says more than my words can. See what you think.

Here are some files to check out. I think the BP40 holds up very well against these mics.

Ty Ford Voice BP40 w/GML preamp

Ty Ford Voice BP40 at WTMD

Ty Ford Voice RE27ND (with peak cut)

Ty Ford SM7 at WTMD (cover removed)

Female VO talent BP40 at WTMD

Female VO talent RE27ND at WTMD

Female VO talent on SM7 (cover removed)

Peavey International II Kick drum

In Conclusion
Like most Audio-Technica mics, the build of the BP40 is very solid. Having a quality, directional hypercardioid like the BP40 in your mic locker will serve you well. Based on my use of it, I'm guessing that it would work or horns, hand percussion and guitar amps as well. It would also probably tame banjos and fiddles.

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Contact Ty Ford at www.tyford.com