Audio-Technica: ATM350a Instrument Mic Systems

The ATM350a is a phantom-powered, small-diaphragm, electret condenser mic with a 12 mm × 38 mm cardioid capsule voiced for close-mic’ing instruments. In many recording situations, it’s an ideal mic for a few key reasons: it sounds neutral, even at close proximities; it can handle high SPLs without overloading; and with an ecosystem of stand-less mounting accessories, you can easily position it to optimize on-axis capture and off-axis rejection, while minimizing physical obstruction.

The ATM350a isn’t sold by itself, but instead, it’s included for purchase in a number of “systems” intended for different instrument mic’ing needs. Five of these systems are groupings of one ATM350a mic with four mounting accessories, a semi-rigid carrying case, and an AT8543 phantom-power module. The sixth system forgoes the power module, so you can pair the system with an Audio-Technica UniPak body-pack wireless transmitter that you supply. The mic has a thin, permanently attached cable that terminates in a Hirose four-pin HR10 connector that mates to the AT8543 (or transmitter), and the AT8543 in turn has a standard XLR output. Hypercardioid and omnidirectional capsule elements are available for purchase separately; these are from Audio-Technica’s UniPoint line of elements for its many gooseneck and boundary mics.

The mounting accessories include two goosenecks (5’’ and 9’’ long) and four gooseneck bases (Drum, Piano, Woodwind, Universal), as well as a hook-and-loop strap (Violin) that holds the mic sans-gooseneck. Each gooseneck ends in a compact, open-cell foam head, into which you insert the mic. The foam offers very little, if any, attenuation of wind noise, but instead functions as a very effective shockmount for mechanical isolation. Along the length of the gooseneck are clips to hold the thin cable extending from the mic. Each base has an octangle receptacle that allows the gooseneck to be inserted and clamped down in one of four angles (curiously, not eight) at 90° increments.

With the 5’’ AT8490 Gooseneck inserted into the AT8491D Drum Mount, the ATM350a has become my go-to mic for recording toms. The AT8491D base, unlike every other drum mount in existence, doesn’t grab the edges of the drum hoop. Instead, it utilizes a rubber-coated metal piece that hooks behind the threaded portion of a tension rod (below the hoop), and it has a receiving hole that captures the top of the same tension rod. This results in the most stable drum mount I’ve ever tried. Ingeniously, the captured rod can still be turned because a standard tuning peg on top of the mount transfers its rotation directly to the rod. (The only time I had a problem with the AT8491D was when a drummer brought in a vintage snare drum with non-standard tension rods.) The gooseneck allows me to position the mic with exacting precision. Because the ATM350a is voiced specifically for close-mic’ing, and its capsule is relatively small, the proximity effect doesn’t really start to ramp up until the mic is within 2’’ of the drum head. During many drum-mic’ing sessions, I preferred the ATM350a farther back than that, because it captures enough low-end — all the way down to 30 Hz — even at 4’’ distance. But in some situations, to boost the lows, I inserted the gooseneck so that it extended sideways out of the mount, which allowed me to bend the gooseneck closer to the drum head. Because the mounting system is so compact and flexible, even tightly packed drum kits and low-mounted cymbals aren’t a problem for the ATM350a. On toms, I found that the ATM350a doesn’t pick up as much “click” as a Sennheiser MD 421, and on snare, it captures less “snap” than a Shure SM57. Personally, I prefer the ATM350a on drums over either of those staple dynamics because the ATM350a has better transient response, and its sound is so easy to tailor. I can readily EQ it to make it sound like I want, due to its smooth, resonance-free, near-flat frequency response. Plus, with its gooseneck, I can quickly angle the mic closer to the drumhead’s center, move it nearer to the drum’s rim, or have it peek over the rim at an angle — to tweak the sound even before I reach for the EQ.

The AT8490L 9’’ Gooseneck and AT8491P Piano Mount combination is designed for recording piano. The rubberized base has a rare-earth magnet inside of it, and it attaches tenaciously to anything made of ferromagnetic material, like the cast iron of a piano’s plate. Setting up this system inside a piano is incredibly quick and easy, because you can place and then aim the ATM350a towards any strings, hammers, or regions of the soundboard of your choosing — without stands or booms limiting reach and taking up space. Because the ATM350a has great rejection, I was able to use a pair of the mics on Piano Mounts inside the open acoustic chamber of my Yamaha U3 upright, even with the rest of the band playing in the same room. Again, the mic’s neutral frequency response allowed me to EQ the recording to taste. I’ve also used the Piano Mount on the steel runners of the spiral staircase in my live room to point an ATM350a into an adjacent wall to serve as a makeshift boundary room mic.

The AT8491W Woodwind Mount is a rubberized base with a hook-and-loop strap that you can wrap around the body of a clarinet, oboe, flute, soprano sax, and the like. The bottom of the base, where it contacts the instrument, is specially shaped to minimize damping of the instrument’s natural resonance. I wrapped the mount near the top of the bell of a clarinet, with the 5’’ gooseneck pointing the mic toward the lower bridge key, and the resulting sound was well balanced. I also tried pointing the mic toward the opening of the bell using a 9’’ gooseneck, but I didn’t like the “honky” sound as much. Wrapped around the head joint of a flute with the 5’’ gooseneck, the mount allowed me to point the mic at the embouchure hole, just far and high enough away that the breathy air wasn’t overwhelming. With the 9’’ gooseneck, I gained more distance and a more natural sound.

The AT8491U Universal Clip-On Mount features rubber-coated, spring-tensioned jaws for clamping onto the bells of brass instruments and saxophones, or to other edges that are thin enough to fit into the 3/8’’ opening of the jaws. A thumbscrew locks the jaws in place, preventing the mount from slipping off. I didn’t have the opportunity to use this mount with any brass instruments, but I did try it attached to the hardware of a cymbal stand, in order to mic the underside of the cymbal, and the mount didn’t budge. By the way, because of the thickness and shape of its jaws, as well as the position of its gooseneck receptacle, this mount will not work on the bottom edge of a drum hoop. On the other hand, you can clip this mount onto a standard drum rim mount, or even to a regular mic clip, so if you want to use this with a mic stand, that’s a quick and dirty solution. In general, the Universal Clip-On Mount was my least favorite gooseneck base; I wish it had a bigger clamping range for more “universality” than it currently offers.

And lastly, the AT8468 Violin Mount, which is included with all six ATM350a system packages, is a simple hook-and-loop strap with a stitched, elasticized section that holds the otherwise naked ATM350a mic. The strap is intended to go around the strings of a violin (or other stringed instruments), between the bridge and the tailpiece of the instrument, pointing the mic towards the bridge. I was skeptical at first with this arrangement, thinking it would pick up way too much bow and not enough body, but I was surprised when the fiddle I mic’d in this way sounded so much better than it did through its professionally mounted piezoelectric pickup. Unfortunately, the mic ended up being directly within the exhaust zone of the player’s nose, so any spirited breathing resulted in loud blasts of air. I didn’t have time to devise a pop filter for the Violin Mount, so I resorted to using the Universal Mount clipped to the tailpiece, with a gooseneck pointing the mic at one of the f holes. Unfortunately, adding mass to the tailpiece did cause a wolf note to appear, but that unwanted resonance was easier to manage than air blasts, and the mic was still far better sounding than the pickup.

All in all, I’m very impressed with the ATM350a mic and its associated accessories. I love the ATM350a for recording drums (especially toms), and it’s also a great option for close-mic’ing many other instruments — on stage or in the studio. It’s a tiny mic with a big sound, and its many mounting options make for effortless setup, without the clutter of mics stands and booms. Because of its neutral frequency response, its tolerance of proximity effect, and its ease of placement, adjusting the sound that it captures is as simple as moving the mic or turning the EQ knobs. Furthermore, a built-in 80 Hz high-pass filter can offset low-frequency buildup if you want to get really close to the source, or you can use the filter to cut out unnecessary rumble. One potential downside is that the mic isn’t suited for quiet sources (published SNR is 65 dB at 1 kHz), which is understandable given that it’s a small-diaphragm electret condenser; but when I used the mic for its intended purposes at very close distances, self-noise was never a problem. Visit Audio-Technica’s website to check which mounting accessories come with each of the six available systems. If you can’t find a system that includes all of the mounting accessories you desire, accessories can be purchased individually.