Capturing Big Sounds

Nov 1, 2007 12:00 PM, By Myles Boisen

           

All about large-diaphragm dynamic microphones.

FIG. 2: Miking the hole in a bass drum’s front head results in plenty of character, but success lies in how well the drum is dampened and tuned. Credit: Myles Boisen

The Obvious Choice: Drums

The powerful low-end response and superior isolation of many large-diaphragm dynamic mics make them a favorite for miking drums, the bass drum in particular.

Inside the bass drum. There are a number of variations in placement on a kick drum. Positioning the mic inside the drum shell — pointed at the beater and close to the beater head — yields a sound that will consist primarily of punchy lows and a well-defined, often clicky, beater attack. When soloed, this type of sound can appear to be deceptively thin and not at all representational of a real bass drum in a room. But when added to a full complement of drum mics, such a close-miked kick tone is often perfect for a range of rock, dance music, and contemporary roots-music styles.

Moving the mic further from the beater head increases the proportion of shell resonance. This generates a more realistic tone, with a fuller midrange and less attack. Adding tone in this manner often makes it more of a challenge to get the kick drum track to cut through a dense mix. But this approach may be more sonically and musically appropriate for a project where the bass drum is not necessarily a central or prominent feature.

Positioning the mic in the center of a hole cut in the drum's front head delivers a fairly realistic tone with a lot of character, but the resulting sound is often lacking in defined attack unless the drum is well tuned and somewhat dampened with a pillow or blanket inside (see Fig. 2). However, with proper tuning and the right beater choice, a drum can have a focused sound at the hole, making this a viable recording method for rock and other styles (see Web Clip 1 and “Capturing the Kit” in the July 2004 issue).

Outside the kick drum. For bass drums without a hole in the front head, close-miking the center of the front head gives the greatest amount of resonance and low end. Moving the mic toward the edge of the head increases the amount of attack and higher harmonics while downplaying the inherent boom of a drum. I often use an intermediate position, at a distance of 2 to 6 inches from the center, to balance low end and attack. Typically, I will roll off some of the low end from a kick drum track recorded in this manner when it comes time to mix.

FIG. 3: In this photo, an Electro-Voice RE20 points between the center and the edge of the bass speaker. Note how it’s angled slightly toward the middle to increase high-end definition and achieve a balanced sound. Credit: Myles Boisen

For most of the bass drum recording I do, the Sennheiser 602 is a fantastic tool. The 602's handling of highs and lows gives me exactly what I need in most circumstances to get a sharp, punchy kick sound with little or no repositioning. This mic also has the ability to extract a usable tone from substandard or poorly tuned bass drums. (For more information on recording bass drum, check out “How to Record a Kick Drum” in the July 2002 issue.)

Toms. The principles mentioned for recording a solid-head kick drum apply directly to the use of large-diaphragm dynamics on rack and floor toms. Positioning the mic closer to the center of the head yields a resonant, bassy tone. Moving the mic toward the edge of the head picks up more of the complex harmonics of the drum and a higher proportion of stick sound.

Two additional issues come into play for this application. The first is obvious: keep your mics out of harm's way by not putting them too close to the center of the head, where the drummer strikes. Unless the drumheads are brand-new, there will be an obvious wear pattern on the head that will let you know immediately where the drummer tends to hit the tom.

The second issue is isolating the toms from cymbal and snare bleed. Dynamic mics tend to be less sensitive to off-axis pickup, but the leakage that does get through can be highly colored, creating problems in the mix. Gating the tom mics is one solution to the problem. Another is careful placement that maximizes the rejection of other components of the kit. When possible, avoid placing tom mics directly underneath cymbals. Position the mics so that the cymbals or other drums are oriented toward the rear of the mic, 180 degrees off-axis.

Beyond the Drum Kit

Any source with significant low-end content is a good candidate for a large-diaphragm dynamic mic. Let's look at some of the more common applications.

Bass cabinet. A large-diaphragm dynamic can be an excellent choice for miking an electric bass cabinet, especially when excessive volume raises concerns about using a condenser mic. Pointing the mic directly at the center of the speaker cone tends to emphasize treble response, upper harmonics, and pick and string sound. A rounder and bassier tone results from moving the mic toward the outside edge of the cone. A balanced tone can often be achieved simply by placing the mic between the center and the edge of the cone, and then angling it slightly toward the middle to increase high-end definition (see Fig. 3).

Bear in mind that many bass speakers these days have low-frequency ports, and often high-frequency tweeters as well. These features need to be taken into account and can either be emphasized or de-emphasized with mic placement.