Definitions of Technical Terms
Note: Several of these definitions were taken from D-TAR (Duncan-Turner Acoustic Research) product manuals. For more information on D-TAR products, go to www.d-tar.com
Active Pickup - A pickup using an electronic preamp to achieve gain enhancement, tonal shaping and/or output impedance reduction. Some advantages include less susceptibility to noise, greater flexibility in creating new tones and the elimination of high frequency losses caused by driving long cables. Active pickups can be particularly useful for producing the strong noise free signal needed to drive multi-effects racks. (For comparison, see "Passive Pickup").
Amplifier - A device for making small electrical signals bigger. The amplifier was actually invented in the late 1800's before there were any devices that could make building one possible! In music, the term often refers to a self contained "combo amp"---an electromechanical device combining a preamp, amplifier, and loudspeaker usually including some kinds of tone shaping circuitry. With Solstice, you have the option of "custom building" your amplifier by matching the preamp/mixer/blender stage to a separate power amp and loudspeaker system.
Buffer - A preamplifier designed to isolate the source from the next stage of amplification. Buffer amps have high input impedances and low output impedances and can also feature some "gain" or signal boosting capability. Buffers are required with piezo crystal or piezo polymer pickups, and are often built into acoustic-electric guitars. Solstice features high impedance buffer stages for both channels so you can use either active or passive pickup systems. D-TAR makes several on-board buffered pickup systems for acoustic instruments.
Cardioid Mic - A microphone designed to be more sensitive in one direction than in others, a directional mic. Cardioid mics are used more often than other types on stage because they make it easier to isolate one voice or instrument from the others for mixing. Hypercardioid mics, sometimes called shotgun mics, are designed for use at a distance as they can be aimed at the sound source and used from many feet away. The good old Sure SM-57 and 58 are cardioid mics.
Chorus - An electronic device that can split a signal, mildly shifting the pitch and timing of one part, then mix it back in with the original signal. The effect is roughly like several people (they're the chorus) playing the same part at the same time. Solstice has effects loops to allow convenient interface with chorus effects.
Compressor - A processor that "squeezes" the dynamic range of the signal by limiting peaks and bringing up the level of soft passages. A limiter can be used to fatten a sound or give it more apparent sustain. If you've ever wondered why music sounds kind of flat on FM radio compared to live, overuse of compression can be one reason. On the other hand, the Beatles used tons of compression on their acoustic guitar recordings and it sounds great. Can be used in Solstice effects loops.
Condenser Mic - A microphone in which an electrically charged diaphragm moves with sound waves while a charged back plate stays stationary. Because the diaphragms of condenser mics can be made very light in weight, the frequency response can be very good with a condenser mic. Neumann mics, considered by many to be the ultimate mics for recording voice and acoustic instruments are condenser mics. "Condenser" is an old term for capacitor. Condensor mic derive their name from the fact that they are sensing the change in capacitance between the diaphragm and the backplate and converting it to a signal voltage.
Contact Pickup - Sometimes called "soundboard transducers" are most often piezoelectric accelerometers (acceleration monitors). They put out an electrical signal that is an electrical equivalent to the mechanical vibrations occurring where they are placed. The D-TAR SA-2 is an excellent example of this type of pickup.
DC Resistance - The resistance to the flow of Direct Current. For most pickups, it is a very general indicator of the output and tonality with higher DC Resistance tending to be higher in output and less bright.
dB - Yes, lower case "d", upper case "B". The "d" stands for "deci"; the "B" standing for Alexander Graham Bell, inventor of the telephone, teacher of the deaf, and co-conspirator with Glenn Curtis in attempts to steal the secrets of controlled flight from the Wright Brothers (see the movie Winds of Kittyhawk). A decibel is a unit used for comparing ratios of signal strengths for acoustical loudness or for electrical audio signals. An expression of dB must be referenced to some other level, as it is not an absolute entity, but rather the logarithmic ratio between one signal strength and another.
0 dB SPL - Is the level at which half of the population of humans with unharmed ears (no Blue Cheer or Barry Manilow music...) can perceive a sound. The "SPL" stands for "sound pressure level."
0 dBV - Is a voltage reference equal to 1.0 Volts rms.
0 dBu - Is a voltage reference of .775 Volts rms, the "u" meaning unterminated, or going into an infinite impedance load. This is the standard used throughout the recording industry.
+4 dBu - Is the standard "pro" audio voltage reference level which is equal to 1.23 Volts rms.
-10 dBV - Is the standard reference level for consumer and some homestudio gear. Often found with gear using RCA connectors.
DI (see also "Direct Box") - The British term now common in the US for "directly interfacing" a pickup signal into a recording or PA console, thus bypassing amplifiers, speakers, and mics. Used especially for electric bass to get a clear tone. Many home enthusiasts directly connect their acoustic guitars to the recording device to gain better isolation from track to track than they can get just using microphones. Solstice has XLR outputs to allow using it as a DI source.
Diaphragm - In a microphone, a thin, stretched, plastic film, the equivalent of your eardrum. The diaphragm vibrates with sound, then transforms that acoustical energy into an electrical signal that can be amplified.
Digital Delay (DDL) - A signal processor that converts analog signals into a stream of digital information that can be delayed and mixed to give echo-like sounds. Digital delay is usually included with other sonic colorings in multi-effects processors. Can be used with Solstice's effects loops.
Direct Box - A device used to buffer or isolate guitar and bass signals so they can be "DI'd". Many of the direct boxes designed for electric guitars and basses do not have a sufficiently high input impedance for interface with piezo pickups. Direct boxes can either be passive, using transformers, or active, using tube or transistor based circuitry. D-TAR's Solstice serves as a high quality direct box.
Distributed Capacitance - The capacitance which exists turn-to-turn and layer-to-layer between the wires of a coil. This property combines with the coil's inductance to produce a resonant peak. Post resonance, distributed capacitance acts like a built-in tone pot and rolls off high frequency response. (See "Resonant Peak").
Dynamic Mic - A microphone which works like a backwards loudspeaker. The diaphragm is attached to a small coil of very fine wire that is surrounded by a magnetic field. When the diaphragm and coil vibrate with sound waves, a small electrical signal is generated in the coil that can be amplified through a mic preamp and other devices. The Sure SM-57 & 58, two of the most common mics used in clubs and studios, are dynamic mics. Dynamic mics are noted for being tough; the mic you can drive a nail with is probably a dynamic.
Effects Loop - A set of jacks on an amp or preamp which allow sending a signal out to an effect and bringing the modified sound back to the main unit. The advantage of an effects loop is that it is buffered (yes, same concept) on the output and input, the effect will "see" a predictable impedance and level, and the modified signal can be master volume controlled in the main amp or preamp.
Electret Microphone - Miniature mics that work on condenser mic principles but have permanently charged polymer diaphragms. Electric mics have miniature preamplifiers built in and require low voltage DC power (usually 1.5 to 18 volts) often supplied as "phantom power." The Seymour Duncan Mag Mic uses an electric element for it's second source with "on-board" blending.
Epoxy Potting - A method of sealing a pickup in epoxy to reduce microphonic feedback and protect the pickup from damages due to handling, exposure to the elements and normal use. (See also "Wax Potting").
Equalization or EQ - An electronic means of shaping frequency response; the term generally refers to sophisticated tone control circuitry. Originally used to mean correction for the unequal frequency response of old PA, recording and playback gear.
External Mic - Generally referring to the good old practice of standing in front of a mic on stage as opposed to installing a mic in your guitar. You've seen them, you've used them, and now you know what they're called. There are now some bracket devices for mounting an external mic on your guitar.
Feedback - Yowl, howl, etc., feedback by any name is the sonic nemesis of the performer. It happens when amplification goes beyond control, and the amplified sound itself is re-circulating and becoming further amplified. The sonic equivalent of Chernobyl---audio meltdown. "Ringing" is the precursor of feedback and refers to a barely controlled resonance just shy of feedback. Seymour Duncan sister company, D-TAR, makes the "Equinox" which features two notch filters designed to combat feedback.
Floating Pickup - A magnetic pickup mounted to the end of the fingerboard on a guitar or to some other non-vibrating part of a musical instrument. Floating pickups are sometimes used on archtop acoustics so the adding of a pickup will not interfere or change the vibration pattern of the top. Seymour Duncan makes a variety of floating pickups including the Bob Benedetto signature pickup for use with archtop guitars.
Four Conductor Wiring - The practice of independent termination of the beginning and ending leads from each coil of a humbucking pickup to a cable with a common shield. This approach allows much versatility in wiring and switching configurations, i.e., series/split/parallel, splitting with coil selection, in/out of phase with itself, in/out of phase with another pickup, etc.
Graphic Equalizer - An equalizer that uses sliding potentiometers (slide pots) to control the level of the signal in various frequency bands. Called so because the knobs form a graphic representation of the frequency contouring. Graphic equalizers are generally either "1/3rd octave" or "1/10th octave" referring to the width of the audio bands covered.
Ground - A common reference point in an electrical circuit.
Hum Canceling, Humbucking - A pickup design consisting of two coils which are summed electrically out of phase and with magnetic polarities reversed. The effect of the configuration is to cancel hum and other extraneous noise and leave the string signal perfectly intact.
Humbucking Pickup - A type of pickup using two coils to cancel magnetically induced hum. Invented by Seth Lover at Gibson in the 1950's, the "humbucker" is noted for it's loud and warm sound.
Hz Formerly known as "Cycles per Second" and named after Heinrich Hertz (not of the auto rental company...), the scientist who in the late 1800s was a pioneer in producing and detecting electromagnetic radio waves.
Impedance - A measurement of the resistance to the flow of AC (which is what audio signals are); impedance is affected by resistance, capacitance, and inductance in a circuit and is also frequency dependent. Impedance is often mistaken for resistance and is also incorrectly thought of as being a measurement of the voltage from a pickup. In practical terms, you want low impedance sources feeding into high impedance loads; this gives maximum accuracy in signal transfer. In passive pickups this figure is variable with frequency.
Inductance - The property of a coil to oppose changes of current through itself.
Internal Mic - A microphone, generally an electric condenser mic, mounted inside an instrument.
Limiter - A limiter keeps hot signals from overloading the next stage of electronics. Les Paul takes credit for inventing the limiters as used in recording studios. He related that he got the idea from watching Mary Ford turn her head while singing loud passages as she watched the recording VU meters. She physically limited the input signal to the mic with this technique.
Line-Level - The voltage level at which most pro gear sends pre-amplified signals to other devices such as equalizers, limiters, compressors and power amplifiers. Generally considered to be +4(dBm) or 1.2 Volts RMS.
Magnetic Pickup - A pickup that consists of a magnetic structure and one or more coils of very fine wire which "transduce" or transform the vibration of plain steel or steel cored wound strings into an electrical signal.
MIDI - Musical Instrument Digital Interface, the computer language used in modern synthesizers and signal processors to "communicate" with other devices.
Milli Volt - One thousandth of a volt.
Mini-Mic Miniature mics derived from hearing aid and CIA "mic in the martini olive" technology. These are generally electret mics, a simpler variation on the condenser mic.
Mixer Used to combine or mix multiple sound signals into a mono, stereo, or other simpler signal to go onto tape, a CD, or through a PA system. Also refers to the person who does the mixing, not to be confused with re-mixer, the person who doesn't mix live, but works on mix-downs of pre-recorded mix-ups.
Monitor Generally referring to a set of speakers aimed at musicians used to give performers a chance at hearing themselves on stage. Watch for "In-Ear" monitors the latest thing in stage monitoring; these are like hearing aids for musicians. The term "Monitor" implies accuracy as well as in, "Studio monitor speaker.
"Natural" Sound Often achieved with the most unnatural of means, natural sound is the Holy Grail of most acoustic musicians. To hear it, try listening to truly acoustic music. Our goal at D-TAR is to help you achieve the most natural sound you can get ... plugged in.
Notch Filter A specialized kind of equalizer that can be tuned to "notch out" problem frequencies without affecting neighboring frequency bands. Usually used to kill feedback frequencies. Equinox features two switchable notch filters.
Omnidirectional Microphone A mic that picks up sound more or less equally in a spherical pattern all around the mic's diaphragm.
Onboard and Outboard Generally refers to where pickup buffering and/or EQ stages are located. Onboard in your instrument, outboard is somewhere else, man.
Out Of Phase - The electrical linking of two coils or two pickups in either series or parallel but with the signal polarities summed in such a way as to provide at least partial cancellation of the signal. Usually the low frequencies are canceled so the resulting sound is thin, lacking in warmth and often quite brittle.
Pa System Originally "Public Address" system. Do you remember, "Would Johnny Brown please come immediately to the principal's office?" Some of the first PA systems were used in department stores and schools. Now the term refers to sound systems designed for amplifying live music.
Parallel - The electrical linking of two coils in a parallel or side by side fashion. The sonic effect compared to a series configuration is approximately 30% lower output but with additional brilliance and clarity on the high end. (See "Series").
Parallel Axis - A patented pole piece system that utilizes four separate small blades per string. The blades are arranged in a configuration that decentralizes and softens the magnetic field providing smoother highs and greater sustain while minimizing distortions induced by string pull.
Parametric Eq A type of equalizer that allows continuous control over three parameters: frequency, bandwidth, and amount of boost or cut. While a bit harder to intuitively understand than graphic equalizers, parametric EQ is preferred by pro audio engineers for fixing specific sonic problems without affecting other frequencies as happens often with graphic EQ. D-TAR's Equinox is a three band parametric EQ with two bands of notch filtration.
Passive Pickup - A type of pickup which uses no internal active electronic circuitry. (See "Active Pickup".)
Phantom Power - A system in which DC current is run up the same cable used to send the signal down to a mixer. Used most often in the studio to power high end condenser mics, but sometimes used for powering mics and other electronics inside guitars.
Phase - The relationship of two wave forms with respect to time.
Phasing - The relative polarity of two or more signals that contain similar information. In-phase signals add together while out-of-phase signals tend to cancel.
Pickup - Any device that changes vibrations of a soundboard or strings into an electrical signal. The most common pickups are magnetic and piezoelectric.
Piezo Pickups & Piezoelectricity - Certain crystals, ceramics, and polymers exhibit the phenomenon of piezoelectricity. Piezo means pressure in Greek, and piezo materials directly transform mechanical vibrations into electrical signals. Most under-saddle pickups, like the Sadducers are based on the piezoelectric effect.
Polarity - The relationship of positive and negative electric currents (or North and South magnetic poles) to each other.
Pole Piece, Non-Magnetic - A ferrous (containing iron, magnetically conductive) metal piece used to control, concentrate and/or shape a magnetic field. Although many styles have been used, pole pieces fall into two broad categories of adjustable and non-adjustable.
At Seymour Duncan, we currently use many different types of adjustable and non-adjustable pole pieces. The physical configuration of the pole piece will vary the magnetic field intensity of the pickup. Generally a more massive pole piece, such as the button head cap screw used in the SH-8 Invaderô, will produce a stronger field. This gives higher output and a more aggressive attack. Smaller or thinner pole pieces tend to produce a lower field intensity giving reduced output and a smoother attack. It is possible to combine two or more types of pole pieces in one pickup in order to achieve a subtle balance between attack, definition, and fullness.
Pole Piece, Magnetic - Refers to a pickup in which the axis of the magnet is aimed directly at the strings and the magnet itself is serving as the pole piece. This design approach is most commonly used on vintage single coil pickups where cylindrical rod magnets serve as pole pieces, however, bar magnets have also been used in this application.
Preamp - An electronic device usually designed for matching low-level signals to a power amplifier. EQ and other signal processing is usually done with or within the preamp stage. Solstice is a preamp in addition to being a mixer-blender.
Presence Control - A section or knob of an equalizer operating in the upper midrange.
Processor - Any signal-modifying device often combining several effects such as
EQ, chorus, delay, and reverb. You can use processors with Solstice by inserting them in the effects loop(s). Digital multi-effects units are commonly used for modifying guitar tones.
Proximity Effect - A characteristic of cardioid mics whereby low end is boosted as you get closer to the mic. Proximity effect can make a mic sound overly boomy if you get too close.
Q - In more musical terms, this refers to the "Bandwidth." At its narrowest setting, you can come close to being able to boost or cut just a single note. Set wider, you can affect a full octave-wide set of frequencies. At a Q of approximately 1.3, the bandwidth is 1 octave. As Q goes up, the bandwidth gets narrower, so at a Q of 2.6, the bandwidth is 1/2 octave.Conversely, at a Q of 0.65, the bandwidth will be 2 octaves.The "bandwidth" or "Q" control is one of the features that make parametric EQ so versatile.
Rack Mount - Gear that is designed to be mounted in the international standard 19" "relay rack". The standard was set by the phone company for its racks upon racks of electrical switches that routed phone calls in days of old when phones had dials and dial tone really meant something.
Resonant Peak - The frequency at which the impedance of a pickup is at its highest. Within a given category of pickups. a higher resonant peak usually indicates a brighter, clearer sound.
Reverb - The sound of surf music, echoey without the discreet pulses or repeats obtained from delay units. The original reverb effect was (and still is) derived from vibrating a set of springs with a little loudspeaker-like driver and picking up the reverberant sound at the other end of the springs.
Ribbon Mic - A type of microphone in which a very thin conductive ribbon, usually aluminum, vibrates in a magnetic field. A small current is induced in the ribbon itself and is then preamped like other types of mic signal.
RW/RP - Stands for Reverse Wind/Reverse Polarity. Refers to the practice originated at Seymour Duncan in the late '70s) of reversing the winding direction and magnetic polarity of one single coil pickup from a two or three pickup guitar. When this is done, hum cancellation can be achieved when using two pickups together.
Scatter Winding - First, let's define some terms.
"Machine Winding" - a machine spins the bobbin and moves back and forth at a regular pace, distributing the wire evenly across the bobbin.
"Hand Winding" - a machine spins the bobbin, but the magnet wire goes through the hands of an operator who distributes the wire along the bobbin. This is how the earliest pickups were wound.
"Scatter Winding" (Also called "Random Wrap") - a machine spins the bobbin, and the magnet wire goes through the hands of an operator (named Seymour) who distributes the wire along the bobbin in an intentional scattered or random pattern. All scatter wound pickups are hand wound. Not all hand wound pickups are scatter wound.
Scatter Winding has a few effects on a pickup's tone.
First of all, when you scatter wind a pickup, you're not placing the wire as close to itself on each layer as you would with a machine. The effect is to create more air space in the coil. This lowers the distributed capacitance. The best way to think of distributed capacitance is like a little tone control in the pickup. When the capacitance is lowered, the result is that more treble will come through and the resonant peak of the pickup will increase slightly. Secondly, each scatter-wound pickup will sound slightly unique. You can scatter-wind ten pickups with the same wire and number of turns, but each will sound different.
Series - The electrical linking of two coils in a serial fashion producing a higher output, fuller and more powerful sound. This is the standard hookup for humbucking pickups. (See "Parallel").
Signal - The word I've used more often than any other in this glossary. In amplification, the signal is the electrical analog of the musical note(s) traveling through the amplification chain.
Single-Coil Pickup - Refers to the simplest style of magnetic pickup having one coil of magnet wire. Noted for a certain clarity and focus. Seymour Duncan is famous for it's recreations of the most famous single coil pickups from the "golden era" of magnetic pickup design.
Splitting, Split Pickup - The process of grounding out one of the two coils of a humbucking pickup thereby producing a single coil sound. (See, for comparison, "Tapped Pickup").
Stack® - Our patented technique of stacking two coils, one above the other, in order to cancel hum and noise but retain a single coil tonality.
Three-Band EQ- Sounds like a good night at the Fillmore, but in our context it refers to types of equalizers having low, mid, and high frequency controls. Solstice features a three-band equalizer on each channel.
Transducer - Any device that changes mechanical or acoustic energy into an electrical signal or vice versa. (i.e. a pickup converts kinetic motion into an electrical signal, a speaker converts an electrical signal into kinetic motion). Mics, pickups, and loudspeakers are all transducers. The term transducer is often used with accelerometer style piezo pickups, but is not exclusive to such pickups.
Transient Response - The quality of how fast a preamp, amplifier, or signal processor responds to an input signal. Related to "slew rate". Fast is good, slow is bad.
Trembucker - A humbucking pickup designed with wider pole-to-pole spacing in order to accommodate guitars with vibrato systems or wider string spacing.
Tube - An electrical device that can amplify low-level signals into higher quivalents. Tubes are the oldest technology for this purpose and are still preferred by many in preamps, direct boxes, and amplifiers. They're made of glass like lightbulbs, and boy, do they get hot!
Tweeter - A loudspeaker designed specifically for high frequencies. Tweeters usually cover the range from 3000 or 4000 cycles (3 to 4 Kilo Hertz) on up to 20 K Hz. Think "Tweetie Bird."
Wax Potting - A method of saturating a pickup in wax to hold the coil and any mechanical parts absolutely rigid. This is done to prevent undesirable microphonic feedback. At Seymour Duncan we use a custom made vacuum encapsulation system to insure thorough wax penetration.
Woofer - A loudspeaker designed for reproduction of low frequencies, generally from 20 Hz to 1 to 3 K Hz. "Midrange" drivers are used sometimes to cover the frequencies between 1 K Hz and 4 K Hz.