EQ Magazine - June 2008 - (Page 34)

DRUM HEADS 10 WAYS TO REDUCE DRUM LEAKAGE by Bruce Bartlett Suppose you’re close-miking a drum set and an acoustic piano at the same time. As the musicians play, you monitor what the mics pick up. When you turn up just the drum mics, the drums sound close-up and tight, but when you bring up the piano mic, the drum sound becomes distant or muddy. This is because the piano mic picked up the drum sound from across the room (Figure 1). In other words, the drum sound leaked into the piano mic, which, in turn, acted like a room mic for the drums. In any multiple-mic setup, sound from an instrument travels to the nearest mic, and also leaks into the mics intended for other instruments. It could be the snare sound picked up by a floor-tom mic, or the drum set sound picked up by a scratchvocal mic. Leakage also comes from sound reflecting off room surfaces. Leakage becomes a big problem when you record loud instruments and quiet instruments simultaneously. Because you typically need more gain on the quiet instruments’ mics, you hear a lot of leakage or “off-mic” sounds in their signals. For certain types of audio productions, it’s very important to minimize leakage, and ensure each mic picks up only its intended instrument. Ideally, you want each mic to pick up only what it is aimed at. Maximizing isolation among mics has several benefits. For one, the drum mix becomes tighter and clearer. Also, if you need to punch-in to correct a mistake, good isolation will reduce ghost drum notes that appear on other tracks due to leakage. Another benefit of isolation is that it prevents the coloration caused by phase interference between mics. Here are ten ways to keep leakage under control. GET CLOSE Mic each instrument closely so that the sound level at each mic is high. The farther a mic is from an instrument, the more ambience, leakage, and background noise it picks up. Close-miking positions can help reject these unwanted sounds. Be aware that close miking can color the tone of a recorded instrument, and this can’t always be fixed with EQ. Do you hear drums in the acoustic guitar track? It might help to mic the guitar a few inches from the soundhole. The tone at that position is very bassy, so cut low frequencies on your mixer EQ until the sound is natural. This way, you can reduce leakage and improve tone quality at the same time. Also, cut a few dB around 3kHz to reduce the harshness often caused by close miking. Is the scratch-vocal mic picking up a lot of drums? Ask vocalists to sing with their lips touching the microphone grille (or its foam pop filter). Turn down excess bass—and minimize plosives— by cutting 6dB around 100Hz or 200Hz. OVERDUB ONE INSTRUMENT AT A TIME This is the most effective way to prevent leakage. You might track all the loud instruments first (drums, bass, electric guitars), and then overdub quiet instruments such as acoustic guitar, vocals, etc.). Overdubbing lets you mic sources from farther away if you wish for a more natural sound. A drawback of this method is that you lose the interaction between musicians that occurs when they all play together. GO DIRECT Try recording acoustic guitar with a pickup, which provides much more isolation than a mic. Also, consider playing electronic drums instead of acoustic drums. FILTER Filter out frequencies above and below the spectral range of each instrument. For instance, remove the highs above 9kHz on the kick drum to reduce leakage from cymbals. Cut frequencies below 75Hz on instruments and vocals (except for bass and kick drum). You might roll off the lows below 500Hz on cymbals if the overhead mics are intended to pick up only the cymbals, and not the entire set. If your mixer or DAW has a sweepable low-cut or high-pass filter, you can reduce a fair amount of low-frequency leakage in the mix. Solo each instrument. Start with the Fig. 1. An example of leakage. The piano mic picks up leakage from the drums, changing the close drum sound to distant. Fig. 2. The angle of best sound rejection for various polar patterns. filter frequency very low, and then gradually turn it up until the sound starts to become thin. Then, back off a bit. GATE Assign a noise gate to each drum track, and set the gating parameters so that you hear each drum hit clearly, but do not hear other drums or cymbals. Make the gate attack time short enough to preserve the attack of the drum, and make the decay time long enough to let the toms ring. NARROW YOUR FOCUS Use directional mics, instead of omnidirectional mics. An omni mic pattern picks up sound equally well from all directions, so it also picks up a lot of leakage. In contrast, a directional mic pattern— cardioid, supercardioid, or hypercardioid— tends to focus on the sound source at which it’s aimed, and partly rejects sounds to the side and rear of the mic. Aim the 34 EQ JUNE 2008 www.eqmag.com http://www.eqmag.com

Table of Contents Feed for the Digital Edition of EQ Magazine - June 2008

EQ Magazine - June 2008 Contents Talk Box Sounding Board 3 Doors Down, Hard-Fi, Paul Manousos Tool Box Panic at the Disco Guitar Trax Bass Management Key Issues Drum Heads Vocal Cords Mix Bus Cheat Sheet Cakewalk Projects Apple Loops Utility SSL Duende Mini JBL LSR4326/PAK & LSR4312SP Holophone H3-D Creation Audio Labs MW1 Studio Tool Amp Modeler Roundup Eventide Timefactor, Electro-Harmonix Stereo Pedals, Korg Pandora PX5D Room with a Vu: Blues Tunes Studios, Silverlake, CA

EQ Magazine - June 2008

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