Audix designed the D6 Sub Impulse Dynamic Instrument Microphone ($349) for use on kick drums, both in the studio and onstage. This rugged and handsome mic is machined from aluminum and is available in a black anodized or a nickel finish (although the nickel costs more). Weighing less than half a pound, the D6 is light and compact, and its cardioid pattern makes it less placement sensitive than Audix's other kick-drum mic, the subcardioid D4. The D6's maximum SPL handling is rated at an impressive 144 dB, but based on my tests that figure seems modest — I couldn't get the D6 to distort no matter how hard I slammed it.
As the D6's frequency-response plot makes clear, “sub impulse” is no misnomer. Its low-end boost peaks nearly 14 dB at 60 Hz and is 4 dB up even at 20 Hz; it then trails smoothly down to flat at around 600 to 900 Hz. The mic's high-end boost is even more radical: 15 dB up between 4 and 5 kHz (the range that engineers typically boost to add “click”) and nearly 17 dB up between 10 and 12 kHz. Despite the big frequency contours, the D6 sounds quite natural.
When the D6 arrived for review, I was in the middle of an album project, recording with my 20-inch Gretsch kick drum (double headed with a hole cut in the front head and some muffling on each head). As good as that drum sounds live, it has always presented difficulties in the studio: it tends to sound too resonant and “boingy” and it never seems quite low enough. The D6 took care of all that and then some. I could hardly believe how good the track sounded in the monitors: huge and fat on the low end, clear in the highs, with practically no boinginess, yet very natural.
My enthusiasm for the D6 only increased as I tried it out on other kick drums. On my 22-inch Ayotte kick, for example, which sounds great no matter what mic you put on it, the D6 provided the best kick-drum sound I've gotten in my studio. It also sounded awesome on a vintage 22-inch Ludwig kick with the front head off. The only kick I tried that wasn't so appropriate for the D6 was an 18-inch jazz-tuned bopper (both heads tuned taut and no muffling on either). On that drum, the D6's big low-end emphasis made the drum sound somewhat unnatural and over-the-top (though still very usable).
The D6 tracks were a cinch to mix, as well. I ended up using the mic on all the remaining songs for the album, and the resulting tracks required little or no EQ during mixdown. If anything, I found myself reaching to turn down the lows — typically a decibel or two at 80 Hz (low shelving) and a few more between 220 and 250 Hz, depending on the song. But I'd rather a mic produce a surfeit of the frequencies I want rather than not enough — it's easy to cut abundant frequencies, but impossible to boost those not present.
Fortunately, I still had my test recordings from a bass-drum mic roundup I wrote with Myles Boisen in 1999 (see “Kickin' It” in the February 1999 issue of EM, available at www.emusician.com). Testing the D6 side by side with seven other kick-drum mics, the Audix D6 compared most favorably. It captured plenty of attack and low end, without sounding unnatural or overly hyped, and without making different kick drums sound alike.
In terms of sheer low-frequency content, the D6 produced by far the biggest, fattest, and lowest lows of the bunch. With the D6, Audix has not only rounded out its Dseries of dynamic microphones, it has added a wonderful and very potent new voice to the world of kick-drum mics.