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The DJ Lounge dictionary. Terms commonly used among audio professionals.
1/4" connector: also known as phone plug. Unbalanced connection using a phone-patching cord.
Anti-skate: counteracts the tone arm’s tendency to pull toward the center of the record. Anti-skating controls adjust to match your cartridge’s recommended setting.
Attenuation: the loss or reduction of amplitude of a signal.
Auxiliary Bus or Aux Bus: a bus dedicated to transmitting audio signals separately from the main bus. See also Bus.
Balanced: a three-wire cord that provides noise-free transfer of audio in areas susceptible to electronic interference, like recording studios and live sound venues.
Beatmatching: also known as beatmixing. Matching up the beats of two tracks so they play simultaneously in order to create a new track or seamlessly transition from one track to another.
Belt-drive: inexpensive turntable design that usually has a motor below and to the side of the platter and drives the platter via a rubber belt.
Biamplification or Biamped: the practice of using separate power amplifiers to drive a woofer and a tweeter in a loudspeaker. Often combined with active amplification, where the amplifier is built into the cabinet of the speaker.
BPM: beats per minute. Measured by counting the number of beats in 60 seconds. Determines the pace or tempo of the music—for example, hip-hop will have a lower BPM (slower tempo) than jungle.
Board: slang for mixing console.
Bus: an electrical circuit that transmits audio signals from one or more sources to one or more other sources. The path an audio signal travels in a mixer.
Cardioid: heart-shaped microphone polar response pattern ideal for live sound.
Cartridge: converts the mechanical energy of the stylus to an electronic signal. Can be identified by its four metal prongs.
Channel: a single path of audio through a mixer, processor array, recording device, or computer interface.
Circumaural: This type of headphone can be closed or open-backed. The term circumaural refers to how it cups your ear. Its padding encircles the ear and forms a seal. These headphones are usually comfortable, and closed-back models provide isolation from external sounds and keep the headphone sounds from leaking out. A circumaural design is a good choice for recording applications and for DJs who need to monitor music in loud environments.
Clipping: distortion due to an overdriven preamplifier or amplifier.
Closed or sealed: These are the most isolating type of headphone. The backs of the earpieces are completely closed, which, along with an effective seal around the ear, prevents sound from passing in either direction. This design is especially good for monitoring in loud environments, and for use in recording because they keep sound from leaking out and being picked up by microphones. They also tend to have strong bass response, so DJs mixing dance music like them. On the downside, they can cause ear fatigue after use for extended periods.
Compression: a reduction in gain or dynamic range of a signal by a compressor. Compression can be used to even out an erratic signal, fatten up sounds, extend sustain of a guitar, sweeten vocals, or push certain sounds forward in the mix of a song by increasing the overall level.
Compressor: a unit that applies compression to an audio signal, usually with controls for sculpting exactly when and how much compression is applied to the signal.
Counterweight: located at the opposite end of the tone arm from the cartridge, it adjusts the amount of tracking force pressure exerted by the stylus on the record.
dB/Decibel: a logarithm that describes the ratio of two powers (1/10th of a Bel). Some approximate reference points: a normal conversation has a decibel level of 60dB, a ringing telephone is 80dB, shouting in the ear is 110dB, and a jet engine during takeoff is 150dB.
Delay: one or more distinct echoes that have a more distinctly audible space between the initiation of the original sound and its reflection and an eventual diminishing of volume over time.
Distortion: any unwanted change that occurs in an audio signal.
Dynamic range: the difference between the loudest and softest parts in a song (usually measured in dB). See also SPL (Sound Pressure Level).
Direct-drive: turntable design in which the motor is located directly below the center of the platter, producing higher torque and allowing the platter to achieve full speed in less time.
Earbuds: Earbud headphones offer the ultimate in portability and light weight. They have no headband or foam pads that rest on the ears. They simply fit into the ear and form a seal that isolates the sound so that only you hear it. The better earbud-type headphones are hard to beat for sound quality, which is remarkable for such small drivers.
Enhancer: also called an exciter. A signal processor that uses frequency analysis, compression, EQ, and filters to add sparkle to audio. Used frequently to bring certain aspects of a song forward in the mix.
Exciter: also called an enhancer. A signal processor that uses frequency analysis, compression, EQ, and filters to add sparkle to audio. Used frequently to bring certain aspects of a song forward in the mix, especially during mastering.
EQ: short for equalization or equalizer. Usually refers to a circuit that provides control over the frequency response of an audio signal that passes through it. Can be used to balance frequencies for more pleasing sound and reduce undesirable frequencies.
Fader: a sliding lever that typically adjusts levels. Has the same function as knob-based controls but provides a smoother response, more fine-tuned control, and visual feedback for quickly determining level.
Filter: an audio circuit that reduces the level of frequencies outside a preset range.
Frequency: the rate of variation of a wave or signal.
Frequency range: the set of frequencies a piece of audio gear is stated to handle with accuracy. Usually specified as 20Hz-20kHz or some variation.
Frequency response: a measure of output amplitude (level or loudness) over a specific frequency range. Simply put, this is the frequency range (or bandwidth) that the unit will pass without severe decrease (attenuation) in amplitude. It is measured in dB and will usually be presented as follows: Frequency Response: +0/-1dB @ 35Hz - 20kHz. This means that there is no more than a deviation in level of -1dB from 35Hz to 20,000Hz, while frequencies above and below that range will be attenuated severely. Increases in amplitude are not discussed in the case of properly designed solid-state devices, since they are the sign of an unstable unit. Tube designs with output transformers will show an increase in amplitude. Even though frequency response is an objective measurement of a unit’s performance, it cannot predict sound quality.
Frequency band: portion of the frequency spectrum, e.g., bass, treble, midrange.
Gain: amplification.
Gain-before-feedback: the total amount of volume possible before feedback occurs.
Headphones: pair of miniature drivers (speakers) designed to be worn on the head for monitoring audio material. Headphones come in closed, open, and semi-open designs. Closed headphones seal the ear off from outside noise for better isolation and are ideal for monitoring during performances and playback. Open headphones sit on the outside of the ear but don’t seal it from exterior noises or the acoustics of the room. Semi-open headphones seal the ear, but usually have a semi-open ear cup, which allows the audio to interact with the acoustics of the room more naturally while still providing some isolation.
Headroom: the difference between the highest signal possible without distortion and the average signal level through a system.
Hertz (Hz): frequency in cycles per second.
Hi-Z: short for high impedance. Z is a popular abbreviation for impedance, hi is simply a shortened version of high. Usually refers to a 1/4" line input with high impedance, typically several thousand ohms or more. Often provided as an input on a mixer, multitrack, or computer audio interface for a guitar or bass.
Hypercardioid: even narrower polar pattern mic than supercardioid for the greatest side-to-side rejection of stray, unwanted sound sources.
ID3: stores information about an MP3 file in the MP3 file itself, usually the song title, artist, album, year, comment, and genre.
Inverse square law: the mathematical relationship of the signal strength and distance, where signal strength is inversely proportional to the square of the distance.
I/O: short for inputs/outputs.
Impedance: the resistance of a circuit to the flow of alternating current, measured in ohms. In audio, impedance is typically classified as low or high and often referred to as Lo-Z or Hi-Z.
Level: the amplitude/strength of a signal.
Limiter: a signal processor that controls the dynamics of an audio signal. Works similarly to a compressor and often used in the same way, but a limiter establishes an absolute output level threshold and prevents any signal that enters from breaking that threshold.
Mixing: the process of using a mixer, either hardware or software, to adjust levels and EQ of an audio performance or recorded audio in an effort to pleasingly enhance and balance the audio.
Monitor: speaker specially designed for high-fidelity playback of audio material. Varieties include near-field, surround, active, and passive. Near-field monitors are designed to be used in very close proximity to the listener to limit interference from the room acoustics. Surround monitoring arrays use all the normal speakers included in a typical 5.1 setup. Active monitors have built-in power amplifiers that eliminate the need for a traditional, separate amplifier component. Passive monitors are traditional speakers that require an external power amplifier.
Noise-canceling headphones: As many commuters know, listening to music while traveling by car, train, or airplane is made difficult by the general level of background noise. For critical listeners, this can be frustrating because it blurs the nuances of the music. Noise-canceling headphones are designed to remove the background noise. They do this by means of phase-canceling technology.
Noise: undesirable or unwanted sound which is introduced to an audio signal by other electronic equipment or excessive gain. Includes hum, hiss, and interference.
Noise Floor: Usually measured in dBV or dBu, this spec is an absolute measure of the mixer’s noise. A mixer with a lower noise floor will be quieter than a mixer with a higher noise floor, hence a lower dB rating is better.
Ohm: one ohm is the measure of electrical resistance in a circuit when one amp of current is flowing with one volt being applied to the circuit.
Omnidirectional: microphone polar pattern that picks up sound from every direction.
Open air: Also referred to as "open-back," these headphones can be either circumaural or supra-aural, but the back of each earpiece is open, allowing sound to escape freely in both directions. Because they are non-isolating, they are not a good choice for recording studio applications. If used by a singer, for example, the headphone sound can leak and be picked up by the microphone and influence the tonality of the final recording. Their positive quality is an open, airy sound that isn’t fatiguing to the ears, which makes them a good choice for general listening.
Peak power handling: the maximum instantaneous, short-term power the loudspeaker can handle.
Phone plug: also known as 1/4" connector. Unbalanced connection using a phone-patching cord connector. The most basic connection in audio.
Phono plug: the more correct name for an RCA plug. This connection was developed and popularized by the RCA corporation in use with their audio equipment, resulting in it being called RCA. Most often used in stereo pairs.
Pink noise generator: makes a sound like a rushing waterfall, meant to reproduce all the sounds that will go through your system during a show by exciting all the audio frequencies with equal energy per octave. Used to test a PA before the show.
Pitch control (also called pitch bend): allows you to adjust the speed of playback in order to beatmatch one record to another. It’s called a pitch control instead of a speed control because as you change the speed of music, the pitch also changes.
Polar response pattern: graphical representations of a mic's pickup pattern.
Power amplifier: Basically there are two types of amplification: the voltage amplifier, which boosts voltage, and the current amplifier, which increases current. The power amplifier is a derivation of the two. In electrical systems and mechanical systems, power is a measure of work, which can take the form of physical work, as in moving a speaker cone, or thermal work (heat), which is actually more common in audio. In an electrical system where voltage, current, and resistance are present, power can be calculated as the product of voltage times current, and is measured in watts, which represents work done over time. (P = V x I — where "P" is power in watts, "V" is voltage in Volts, and "I" is current in Amps.) In terms of physical work, voltage would equal an amount of weight being lifted and current would be the speed at which it’s lifted. In the audio chain, we generally have a preamp followed by a power amp. The preamp boosts a low-level signal to line level, which is an increase in voltage (but not a significant increase in current). The power amp, which is the last stage in the chain, provides current via its power supply and boosts both it and the voltage from the preamp in order to provide enough power to drive a loudspeaker.
Power conditioner: an electronic device that sits between a wall outlet and electronic equipment, which provides protection against spikes and surges in power. Typically conditioners also provide some type of noise filtering against electronic signal interference.
Portable headphones: These are the open-air, lightweight, foam ear pad headphones used with portable players of various sorts. Often the ones that come with players are cheap and you may want to replace them with better quality headphones of a similar kind. They are light which makes them ideal for active wear, and the better ones can sound fantastic. Because they allow you to hear external sounds such as that runaway garbage truck bearing down on you, they are suited for use during activities where awareness of your environment is important.
RCA: see phono plug.
Reverb: a series of multiple sound reflections that extend the impact of the original sound. In nature, this is caused by a sound that originates within a space enclosed by hard surfaces. Also refers to the electronic equipment developed to replicate this acoustic phenomenon.
RMS or root mean square: the square root of the average (mean) of the squared values of all the instantaneous voltages on a waveform. Continuous power handling is sometimes—though technically incorrect—called RMS.
rpm: revolutions per minute.
S-shaped tone arm: pulls toward the outside of a record and uses an anti-skate mechanism to counteract this pull. S-shaped tone arms position the stylus at the optimum angle for sound quality and the S shape dissipates external vibrations.
Semi-open: This type of headphone, as the name suggests, falls between a fully open design and a closed-back design. While some sound leakage can occur, there is less than with an open-back design. Semi-open headphones usually offer a realistic stereo field, low distortion, and extended low-frequency response. They are often used for recording where there are no open microphones to pick up resonance from them.
Send: An output on a mixer that sends that channel’s audio to wherever the send is routed. Sends included level controls and can be used for routing audio to external signal processors and usually include a return input as well so that the audio can be returned to the mixer.
Slew rate: the amplifier's ability to react to quick changes in signal voltage. For amps rated up to 100W continuous, the slew rate should be at least 10V per microseconds. For amps over 200W continuous, it should be at least 30V per microsecond.
Signal processor: generic term which loosely groups components such as compressors, limiters, equalizers, microphone preamps, noise gates, reverbs, chorus, delays, modulation, filters, and enhancers/exciters. All are used in audio to process sound in order to achieve a desirable effect.
Signal-to-noise ratio (SNR): the ratio of the desired signal’s volume to the unwanted noise, usually measured in dB. Manufacturers measure this ratio in many different ways, but basically the higher the number, the better and cleaner the signal.
Sound Pressure Level (SPL): the strength or intensity of acoustic sound waves, measured in dB. A typical SPL reading for a rock concert is 95dB.
Stereo: 2 channels of audio, usually designed as left and right.
Straight tone arm: exerts no inward or outward force relative to the platter. Straight tone arms minimize the risk of skipping at the cost of increased record wear and decreased sound quality because the angle of the needle doesn’t line up straight with the grooves.
Supercardioid: narrower microphone polar pattern for better sound isolation.
Stylus (needle): the tip (and cantilever holding it) that picks up vibrations from the groove in a record so it can be translated into sound. These tips are usually made of industrial-grade diamonds to withstand the extreme pressure and heat generated as the tip goes around a record groove. Spherical (conical) styli feature a small sphere at the tip and are better for scratching, while egg-shaped elliptical styli are better for general-purpose use.
Supra-aural: Headphones of this design are similar to circumaural headphones, except that instead of encircling the ear, they rest on it. Usually these headphones are lighter and therefore more comfortable. But since they do not seal as well as circumaural headphones, they are not as isolating.
THD+N: acronym for Total Harmonic Distortion plus Noise. Smaller is better when it comes to this spec, which measures how transparently the mixer will reproduce music without distorting it.
Tone arm: the arm that holds the cartridge and points it in the right direction. The tone arm height is sometimes adjustable (most DJs leave it all the way up).
Tracking force: the downward force that allows the stylus to stay between the walls of a record groove. Adjustable via the counterweight.
TRS: stands for Tip, Ring, Sleeve. TRS is a balanced circuit that uses a phone plug-style connection with three conductors (the tip, the ring, and the sleeve) instead of just two (the tip and the sleeve).
Unbalanced: an audio circuit whose two conductors are unequal at ground, usually because one conductor operates as ground. An unbalanced audio circuit is more susceptible to noise problems than balanced circuits. Noise can be combated by keeping lines as short as possible.
Unidirectional microphone: mics that are most sensitive to sources directly in front of them, minimizing off-axis sound and background noise.
Wireless headphones: There are a number of wireless headphones available. The advantage of having no cable is obvious. You’re free to roam as you listen. There are three basic types: infrared, RF, and digitals. Infrared models have a shorter reception distance and require line-of-sight orientation to the base unit transmitter. The RF models transmit further and will work through walls, but noise and sound quality can be an issue. Digital wireless converts signals to a digitally encoded signal, then the headphones convert it back to analog. This type is more noise-free than infrared and RF but more expensive. They also require power for the transmitter and battery power for the headphones.
XLR: a balanced, circular 3-pin connector typically used for microphone and line-level signals. Developed by the Cannon company, it is sometimes called a Cannon connector.
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