The Impact Of Effects On Recorded Drums

Reverb

The purpose of reverb (reverberation) is to make studio recordings sound as if they were done in live acoustic spaces, such as a recital hall, gymnasium, or tiled bathroom. In the glory days of analog recording, the “reverb” was often a cement-lined room in the basement of the recording studio, with a speaker at one end to fill the room with sound and a microphone at the other end to pick up the echoes. Today’s digital reverbs are quite a bit more convenient, and when adjusted carefully they can sound very good indeed.

Digital reverbs come in two basic flavors: standard and convolution. Convolution reverbs (Fig. 4) are typically more expensive and put more demands on your computer’s CPU because more mathematical computation is required. For many musical purposes, a standard reverb will work just as well.

When a sound is played in an actual room, it bounces off of the walls and other nearby surfaces. The first few bounces can sometimes be heard as separate echoes, especially if the room is large and the walls are concrete. These separate echoes are created in a digital reverb as “early reflections.” You’ll probably be able to control the level of the early reflections as a group. The later reflections blend together in a continuous wash of sound, which is called the decay or the tail.

Most digital reverbs let you set the decay time, which is the amount of time it takes the tail to die out. You may also be able to control the density or diffusion of the tail. A low density or diffusion setting will cause the reverb to sound rather artificial and metallic, which may be exactly what you want. Higher density and diffusion settings sound more natural. You may also find a “room size” parameter that’s separate from the diffusion (Fig. 5).

Sound travels at roughly one foot per millisecond. In an acoustic space, if your drums are 50 feet from the nearest wall, you won’t hear any reverb at all for 100 milliseconds (1/10 second). To simulate larger spaces, reverbs have a parameter called “predelay.” Increasing the predelay gives a more cavernous effect, and reducing it makes the simulated room seem smaller.

Export Final Mix

This has been a short-and-sweet overview of effects for recording novices. Keep an eye on future installments of Plugged In. I’ll be covering a few other types of effects in shorter articles.

Frequency Range

Frequency is measured in Hertz (Hz). The range of human hearing is generally capable of anything from 20Hz to 20,000Hz. Large Hertz values are usually stated in kiloHertz (KHz). One Hertz equals one cycle per second. All sounds in nature contain partials (overtones) at various frequencies. If a sound has partials at a given frequency, an equalizer can cut or boost them without affecting the rest of the signal. But if the sound has no partials in a certain frequency range, adjusting that range with the equalizer will do nothing. The amount of boost or cut is defined in decibels (dB). Decibels are usually referenced to a 0dB level; 0dB means “no change,” not “no sound.” If we cut a certain frequency range by 6dB, we say that it’s set to -6dB. As a rule of thumb, 1dB is about the smallest amount of change that an average listener can perceive. When talking about EQ, producers and engineers often use somewhat vague terms rather than referring to frequency ranges by the numbers. The highs in a track are generally the frequencies above 8kHz — except that, if it’s a bass track, the “highs” might be as low as 2kHz. These terms are relative. The high mids (high midrange frequencies) are in the 2kHz—6kHz range, the low mids in the 800Hz—2kHz range, and the lows are whatever is going on at the bottom. Terms such as “nasal,” “boomy,” and “hollow” are often used to describe EQ contours. Their meanings are fairly obvious. As you spend time listening to tracks that have been EQ’ed, or need to be, you’ll become more sensitive to what various frequency ranges sound like.