Pursuit Of The Perfect Drum Sound
Tools Of The Trade
When people tour the studio one of the questions we always get is, “Why do you have so many microphones?” The short answer is we record many different things. No single mike is the best choice for every source, and a bass drum is no exception. Talking with producers and engineers reveals a short list of frequently used microphones, which range in price, type, and design. For discussion purposes, I’ve broken them into three categories: dedicated, conscripted, and inventive.
Born To Kick
Several manufacturers market microphones specifically dedicated as bass drum mikes. These are designed to be durable and handle high sound pressure levels (SPL). Additionally, dedicated kick mikes have diaphragms suited for low frequency reproduction, and have a cardioid or hypercardioid pattern to help reject bleed from other drums.
Internally, dedicated kick mikes usually possess a frequency response tailored for the instrument. Designers alter the mike through air porting and electronics to provide a more pleasing kick sound. Think of it as a built-in equalizer. Most have a low frequency boost at the bass drum’s fundamental, the boom of the midrange is often reduced, and a second boost at a higher frequency is added to capture the beater attack. The big three dynamic kick microphones include the AKG D112, Audix D6, and Shure Beta 52. Pulling manufacturers’ published specification and response curves reveals the profiles in Fig. 2.
Note the diverse approaches to optimal low frequency and optimal high attack frequency. Each microphone is different! Now, recall how each kick drum has a natural pitch. Knowing these facts, which mike is the best? Answer: it depends. (I’ll also give full credit for “all of them”). Given 100 random kick drums and these dynamic mikes, some microphones will sound better with some drums than with others. So, if you’re recording your kit at home, you may find one of these mikes best suited to your personal kick. But if you are a sound professional, you probably want to buy them all. Actually, if you record double bass you need two of each. (Don’t write in to yell at the editor. We’re just the messengers. Blame physics.)
Dynamic mikes are usually placed inside the kick drum. Their SPL tolerance ensures their survival, while their built-in equalization response helps cap- ture both the boom and the click. They’re also happy to be placed on the resonant head or just inside the port on a vented front head. If you can have only one kick mike, the oddsmakers suggest you pick one of these three.
Fig. 3 Not all ribbons are equal. The Royer 121 can take the sound pressure of the front head, provided you angle the microphone. This allows the soundwaves to travel along the ribbon, thereby distributing the stress. If you’re unsure, moving a ribbon microphone away from the bass drum is a safer option, especially a vintage model like the RCA 44.
Recording engineers are a zany bunch. They rarely read directions or owner’s manuals. Consider the microphones they’ve borrowed from other fields to record bass drums. The Electro Voice RE 20, Sennheiser MD 421, and Telefunken M82 are more natural-sounding broad- cast mikes. It bears mention- ing that the Telefunken is dual purpose, with both vocal and kick drum-specific equalization circuit choices. The Crown PZM-30D is a pressure zone microphone, which is a small diaphragm condenser specifically paired with a hard surface to create a “sound grabbing field.” Although some companies make kick-drum labeled pressure zone microphones for internal use, the Crown PZM-30D is often used outside the kick for purposes of low-end augmentation. The Royer 121 (Fig. 3) is a modern ribbon mike that can be used to capture the resonant head. Neumann’s U47 FET, with its complex and wide-frequency responsiveness, is a staple external mike for those fortunate enough to own one.
Broadcast dynamics are used interchangeably with dedicated dynamic kick microphones. Stick them inside the drum and record. Their frequency response is flatter, or more natural, leaving equalization duties for mix time. You will need to scoop out the unneeded lows and mids to make room for the bass guitar, but otherwise, these make for fine options.
The Royer 121 can be a life-saver in some instances. Royer reports that the mike can be placed a few inches from the resonant head, provided you angle the mike at a 45-degree plane from the drum. Note that this is different than keeping the microphone perpendicular to the floor and rotating the axis. Imagine the mike bowing to the kick as if it were a martial arts contest; this angle distributes sound pressure down the ribbon as opposed to hitting the entire element at the same time. I pre- fer the 121 a few feet away from the bass drum, but about a foot off the ground. The Neumann U47 FET is glorious as a front head microphone. Most people choose to keep it off center and about 3—4" from the head. It can capture every nuance of the shell while picking up some of the initial hit of the beater. The U47 FET-plus-broadcast-dynamic combination is probably responsible for more modern kick drum recordings than we could count.