Adding to its respected Sound Isolation line of acoustical products, Auralex has released the Aural-Xpanders ($49.95). The 13-piece kit includes a 14-inch Xpander baffle, a pair of A-shaped Tri-Xpander baffles, four Trap-Xpander baffles, and six PlatFeet. The collection provides enough absorptive material for seven microphones and two mic stands — perfect for tracking a modest-size drum set. Auralex also offers the ISO Producer Pack ($119), which includes everything in the Aural-Xpanders kit as well as a set of MoPads Monitor Isolation Pads (reviewed in the July 2003 issue of EM) and a GRAMMA isolation riser.
The PlatFeet, which are designed to isolate the legs of a mic stand from a noisy floor, sparked my initial interest in the Aural-Xpanders. Most of my recording time is spent tracking concerts, and even when my mics are in a shockmount, it's easy to pick up the footsteps of an audience member walking by the mic stand. The PlatFeet seemed like a great solution for reducing this type of floor-based rumble.
Each of the pads has a 4-inch by 3-inch base, with a large notch cut into it from the top. The notch is cut inward so the extra foam wraps snugly around the stand's legs and keeps the pads secure. In the middle of the pad, on 0.5-inches of foam, is a plastic strip on which the legs of the stand rest. The strip helps protect the foam from damage over extended use and helps distribute the weight of the stand.
As I had hoped, the PlatFeet work like a dream with mic stands, and they are small enough to fit into my cable bag. Auralex also suggests using the PlatFeet on the legs of floor toms and cymbal stands to decouple them from noisy drum platforms and stages.
A Baffling Revelation
The Aural-Xpanders kit also includes pieces of foam designed for placement directly behind microphones. These mini baffles are especially useful in situations where you want to minimize 180-degree off-axis sound, but not completely isolate the mic from the resonance of the acoustical space — or block a performer's sightlines — with a gobo or large baffle.
Three sizes of baffles are included. The largest, the Xpander, is an hourglass-shaped piece of foam designed for use behind large-diaphragm mics. The outer edges are 7.5-inches wide, tapering to 5-inches in the middle. A hole in the center, with a slice leading to it on one side, allows you to easily attach the baffle to a mic stand. Exactly where you place the baffle behind the mic determines the balance of wanted and unwanted reflections, and the simple design of the Xpander lets you make adjustments easily.
The Tri-Xpanders are half the size of the larger Xpander and can be used with smaller mics. Their convenient size and shape also makes them perfect for isolating a pair of mics from each other (for example, when you're recording a singing acoustic guitarist and you want to minimize vocal bleed into the guitar mic and vice versa). The Tri-Xpanders also have a hole in the middle and easily attach to a mic stand.
While using these larger pieces on a session with horn players and a vocalist, I was concerned that the musicians (particularly the singer) would be distracted by having a foam wedge more or less in their face. However, no one minded, and the foam was a big help in filtering out unwanted coloration.
The asymmetrical Trap-Xpanders wrap around a small diaphragm mic and are designed for use on drum and percussion setups in which you want to lower the bleed of adjacent instruments. The foam pieces are 6 inches long and 1 ½ inches at the thickest point (with ridges cut into one side), and they taper from 3 ⅞ inches wide at one end to 2 ⅞ inches at the other end.
Placed around a snare drum mic, the Trap-Xpander can noticeably reduce hi-hat coloration in the snare mic. Positioning the foam is the key to success. With four Trap-Xpanders included in the kit, you have enough foam to isolate a snare and three toms. In a live session, I added a Tri-Xpander behind the bass drum mic to effectively lower the bleed from the horn players in the room.
Cut It Out
I'm always looking for ways to further isolate mics in a multimic setup without using up what little space I have. In these situations, the absorptive goodies in the Aural-Xpanders kit efficiently help to reduce problems due to off-axis coloration. And the PlatFeet are great for recording shows. At this price, the Aural-Xpanders are irresistible.