Wednesday, June 13, 2012

Audio Technica 4047/SV FET Borrows From The Past


Audio Technica AT4047
In today's overcrowded condenser mic market, a neutral mic easily gets lost. To stand out, you need some attitude. That's what the other mic makers are doing, and Audio Technica is now following suit. The AT4047/SV FET cardioid condenser microphone ($695 with mic, vinyl case and suspension mount) is a marked departure for Audio Technica. 

Most of their mics are relatively neutral. The AT4047/SV is not. The company line on the AT4047/SV is that it's "The perfect blend of classic sound and modern precision engineering." Distill the ad copy and what you get is, "new stuff with old stuff." The new stuff is quieter electronics; an extremely respectable self noise of 9dB-A, a whopping output (17.7 mV +/- 2dB @ 1Pa), and a typical dynamic range of 140dB. The old stuff is the use of a new output transformer. 
The right transformer can add attitude. According to Bob Green, Engineering Supervisor Engineer for Audio Technica here in the States,"We've been building our own large capsule mics with dual diaphragm mics starting with the AT4050 back in 1994. We were out to get the old characteristic of an early transformer output coupled condenser mic, but with better manufactured circuitry and elements. 

The transformer is custom wound based on work done in our main development lab in Japan." Green says Audio Technica used some similar circuitry with their latest tube mic, the AT4060. "The capsule of the AT 4047/SV is loosely based on the AT4060, but the diaphragm tension, baffle and other things have been modified." Green notes that both mics use dual diaphragm capsules that help to control the pattern, even though they're a lot more expensive than single-sided capsules. As a side note, the AT4060 is a very transparent and open sounding mic and should do well, but it doesn't have, well...attitude.
I first compared the AT4047/SV to a Neumann TLM 103, through GML mic pres. Although the AT4047/SV has 2dB more selfnoise, it also has about 3-4dB higher output than the TLM 103. When the mics were trimmed for equal level, the selfnoise difference was almost undiscernable. The TLM 103 is smoother and has a thicker sounding bottom. Both mics have somewhat similar midrange meat, but the AT4047/SV has a little bite below the top and a bit more open upper midrange presence. The bite reminds me of that which an API mic preamp imparts on the audio that passes through it. More on that later.
PATTERNS & REJECTION
Both mics develop some phasey artifacts when worked at or past 45 degrees off axis and both lose low frequency response at 90 degrees off axis. Rear rejection was good in both mics, with the TLM 103 losing more high frequencies off the back. Both mics distorted during the key jangle test, with the spectra of distortion being higher in the TLM 103 and lower in the AT4047/SV
IN THE BOOTH
For voiceover work, the endearing low frequency proximity boost of many large diaphragm condenser mics gets in the way when the mic is worked any closer than about 6-8 inches. Without the LF rolloff (80Hz, 12dB/octave), the AT4047/SV does exhibit proximity, but has less bottom and proximity than the TLM 103. I could work a quiet voice within an inch of the grille, but not without eddys or popping. With the mic's 80 Hz rolloff engaged, I could easily work up close with only minor pops and eddys. With care, a pop screen, and rolled off, the 4047 can be used as an on air mic, no question. With a foam ball on the mic, I lost just a bit of the edge and gained a lot of control over popping.
Regardless of my earlier comments about the AT 4047/SV not having the bottom that the TLM 103 has, it still has enough to require the bass rolloff and some EQ to keep my Martin D28S fifth and sixth strings from booming. 

The D28S doesn't have the "boom" that a standard dreadnought has, but it's not bass shy either. At those frequencies (basically 80Hz to 110Hz), the mic's 80HZ 12dB/octave rolloff and the 75Hz 18db/octave filter on the Mackie are not usable because they are below the problem frequencies. Tracking flat and directly into my Orban Audicy workstation with the AT4047/SV about six inches out from the soundhole, I found pulling down 7.7dB at 118Hz with a .28Q rebalanced the bottom nicely. 
Next I pulled the mic back to one foot because that's where the handy spec sheet said the mic would provide a more or less flat response. Again, shooting right into the soundhole, I recorded flat. This time, without changing the Q, I only needed to drop 110Hz by 3.8 to 4.9dB. I then moved the mic so that it was about a foot out from the neck/body joint and angled to the soundhole. I still got a very full bottom that required some LF cut. The point here is that for music recording, having a room that either sounds good or doesn't contribute at all with a mic a foot away from the source is a good thing. If your room is not that good, you'll have to move in and deal with the increased bass proximity effect. Note that I didn't have to do any bass tailoring for my voiceover recording. 
Whereas the TLM 103 is a mic with a bigger bottom and more lower midrange, the AT 4047/SV shows more in upper midrange presence. One way of looking at it is that the TLM 103 sounds more intimate...close and warm. The midrange presence of the AT4047/SV makes for a clearer sound. 
FLITE THREE
While the legendary Neumann U 47 is never mentioned in the Audio Technica literature, one might surmise that the intent was to get close to its sound. I stopped at Flite Three in Baltimore to put the AT4047/SV up against their U 47 FET and U 87i. Working with engineers Louis Mills and Mark Patey, using an aging but very respectable API console, we found that the AT4047/SV sounded more like their U 87i (not ai) than it did like their U 47 FET. The AT4047/SV was brighter in the presence range than either the U 87 or U 47. 
I mentioned earlier that the AT4047/SV through my GML mic pres had an edge that reminded me of the API mic pre edge. Since the GML has never produced any sort of edge, I ascribed the edge to the sound of the AT4047/SV, perhaps due to its transformer. Flite Three's API mic preamps did add their own edge. The combination of the mic edge and the preamp edge didn't increase the size of the teeth in the edge as much as it sounded like twice as many teeth of the same size.
The key jangle test at Flite Three supported my earlier listening experiences. All mics crunched a bit, the AT4047/SV crunch showed its affinity for upper midrange presence. We did notice one anomaly while recording Tom Olsen, a local V/O talent. At a distance of six inches, using an aggressive style the U 47 sounded more edgey, while the AT4047/SV became less edgey. I'm not sure which one changed, maybe both a bit. 

The U 87 exhibited more bass than the AT 4047/SV. At six inches the U 87 and U 47 popped, but didn't splat. The 4047 was a bit more resistant; woofing, but not popping. At a foot the bass response of the AT 4047/SV drops off; more so than the U 87. After his brief experience, Olsen offered his own capsule review, "The U 87 had a bigger bottom, the U 47 sounded fuller across the spectrum and the AT4047/SV offered more midrange." At that point the agency producer came in and we used the AT4047/SV on Tom's voice to cut spots for the Pittsburgh and Cleveland markets. Without EQ, the midrange presence allowed Tom's voice to ride nicely over the music track. 
PATTERN COMPARISONS
Checking the patterns of the mics we found the sweet spot of the AT4047/SV was slightly wider than the U 87. At a distance of about four inches, an inch either side of center took us out of the U 87 sweet spot. The AT4047/SV gave us a swing of about two inches either side. 

The AT4047/SV did best at a distance about four to six inches. Any closer and things started to get muddy and ugly. Since I had been able to get closer at my own studio, I can only guess that the difference in preamp/mic coupling was responsible for the differing results. The AT4047/SV picked up more high frequencies from the rear side and grille top than the U 87. At a distance of four feet, the AT4047/SV heard more of the room, the U 87 heard less room but its selfnoise was more apparent. 
IN CONCLUSION
To my knowledge, this is Audio Technica's first time out with an "attitude mic." Hopefully people will get past their preconceived notions about Audio Technica and give the AT4047/SV a try. Incidentally, the first 600 were sent to the distributors in a tweed road case. If you're lucky and quick, you may be able to get one. And try that AT4060 tube mic. I personally think it's the sleeper of the year.
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