Glossary
3dB POINT
The point on the frequency response of a unit where the signal level is 3 decibels lower than the maximum level.
ACTIVE
Any audio circuit that requires a power supply. An active circuit has the benefit that it can include gain (signal increase). All AudioControl Equalizers and Crossovers are active components.
AMPLITUDE
A measure of the strength or voltage of a signal.
ANALYZER
(see Real Time Analyzer)
AUTOMODETM
An AudioControl exclusive feature that routes input signals to an additional set of outputs, commonly subwoofer outputs.  This is ideal when expanding 2 and 4 channel systems.
BANDPASS FILTER
A combination of a lowpass and highpass filter. The bandpass filter has rapidly decreasing output above and below its 3dB frequencies.
BANDWIDTH
The area of frequency spectrum between the two 3dB points of a bandpass filter.
BARISTA
The individual who makes our espresso each and every morning.
CENTER FREQUENCY
The frequency at which the output signal from a filter reaches its highest or lowest point.
CHANNEL SUMMING
The ability to combine two or more signals together, commonly used to produce a full-range signal (20-20KHz) from multiple crossed-over signals.
CONSTANT-Q
An equalizer design topology that maintains a constant bandwidth regardless of the boost or cut level. We use this design on our higher resolution (one-third octave and higher) equalizers to get the best possible sound and make them easier to adjust.
dB
The standard abbreviation for decibel. See also Decibel
DECAY
The rate at which a spectrum analyzer display changes. A fast decay rate reacts faster to changes in music. A slower rate is better for doing response analysis. Also, the smell of rotting leaves in a Northwest forest.
DECIBEL
(Abbreviated dB) The unit of measurement used to describe a signal level or volume level. This is a logarithmic scale so an increase of 3dB is double the level. (3dB=2 times, 6dB=4 times, 9dB=8 times, etc.) Equal to one-tenth of a Bel.
DUAL-BANDWIDTH
An exclusive AudioControl feature that combines two different bandwidth equalizers. This allows more accurate adjustment in the areas (such as bass) where a system needs it.
EQUALIZE RECORDING
A switch, which automatically channels the equalizer's output into the tape deck. Allows the customer to equalize tapes without reconnecting the patch cords.
EQUALIZER
A rather inappropriate name for multiple tone controls, since they have many functions other than just compensation. But that's what they've been called for 30 years and if we started calling ours Bzerndnyxx's, you wouldn't know what we were talking about.
GRAPHIC
This type of equalizer has controls on fixed center frequencies and bandwidths with adjustable amplitude. These equalizers usually have slider type controls so the adjustments form a "graph" of the frequency response.
GTO
The Great Turn-On is a signal sensing circuit that powers up a unit when a signal is present. Just another AudioControl exclusive that makes our products so great.
INFRASONIC
These are frequently also referred to Subsonic.
Frequencies from 1 to 20 Hz which are inaudible but which causes visible oscillation of the speaker woofer cone caused by turntable resonances, floppy floors, acoustic feedback, bad recordings, and aggravated by vented speaker systems cause great unnecessary use of amp power, IM distortion and occasional woofer destruction.
INSERTION LOSS
The amount of signal level decrease caused by placing a passive audio device into a system. The crossovers built into all speakers is a good example of a passive device.
INTERNAL SIGNAL SUMMING
An AudioControl product feature found on OEM interface products like the LC6i and LC8 that allow you to safely and easily combine or "sum" 2 or more pre-amplifier signals together into a single output within the unit. No additional RCA cables are necessary. Internal Signal Summing is useful for creating full-range (20hz - 20khz) signals from crossed-over signals typically found in newer OEM systems.
LED
Light-Emitting Diode. A small semiconductor capable of almost instantaneous light display Frequently seen as useless bells and whistles on everything from toasters to whoopee cushions, but also a perfect way to construct an affordable real-time frequency analyzer display.  
LINE LEVEL
Refers to the output level of a power amplifier, capable of driving a speaker - same as Pre-amp Line Level
LINE OUTPUT CONVERTER
Device for converting a powered (or amplified) signal into a pre-amp line level (or non-powered) signal
MEASUREMENT MIKE
A special microphone designed for frequency response determination. It's either perfectly flat, or any response anomalies have been compensated for in the measuring system. Generally costs mucho bucks. Ours is perfectly flat from 20-20KHz and is remarkably affordable.
MUKILTEO
Where we're all going to retire after we sell zillions of equalizers and sell out to General Foods of Saudi Arabia in 2010.
OCTAVE
A method of dividing up the audible frequency spectrum equally into ten bands. Each octave center is twice the frequency of its next lowest neighbor.
OEM
Original Equipment Manufacturer, sometimes referred to as "Factory" or "Stock".  This term refers to the equipment (including the stereo system) that comes from the manufacturer of the car. 
OEM INTEGRATION
The ability to allow high performance aftermarket audio equipment to work in conjunction with systems and equipment installed by the Original Equipment Manufacturer or factory.
PARA-BASS
An AudioControl exclusive feature, Para-bass equalization controls allow  you to select a bass frequency that works the best for your systems and apply the appropriate amount of boost or cut.  In addition, the bandwidth or "Q" is automatically adjusted based on the frequency you select.
PARAMETRIC
On this type of equalizer you can adjust all of the parameters: Amplitude, Frequency and Bandwidth. They are typically only found in professional applications due to the difficulty in properly setting all of the controls.
PASSIVE
A device with no power supply. This type of audio circuit will always have some insertion loss.
PFM
Programmable Frequency Match. An exclusive AudioControl feature that allows the system installer to set the subsonic (highpass) filter frequency to match the system's speakers.
PINK NOISE
Equal amounts of sound energy in each octave of the sound spectrum A perfect test source for frequency response measurement since it's perfectly flat and any dips or bumps can be attributed to room acoustics or speakers when displayed on a real-time analyzer like our C-101 or R-130.
PRE-AMP or LINE LEVEL SIGNALS
Refers to the non-powered audio signal going into a power amplifier, typically through RCA connectors 
Q       (see Quality Factor)
QUALITY FACTOR
Also known as 'Q'. Another word for bandwidth. Q is defined as the center frequency divided by the bandwidth.
REAL TIME ANALYZER
A device which displays frequency response measurements provided by microphone in conjunction with a pink noise source. Useful in equalizing room acoustics, improving speaker performance, analyzing music and optimizing tape bias and EQ. Most units retail at between $2000 and $5000.
RUMBLE
Audible low bass garbage caused by turntable defects, records warps, acoustic feedback and arm resonances. Typical equalizer settings may accentuate rumble, so we built a rumble reducing circuit into our Richter Scale that automatically "mono's" bass under 200Hz at the push of a pinkie. See also SUBSONIC.
SKIRT
The skirts of a filter are those frequencies that lie above or below the center frequency. Also, a piece of cloth wrapped around the legs.
SOUND PRESSURE LEVEL
A measure of sound intensity, or loudness. Measured in decibels or more correctly, dBA. The noise around a typical city street measures 60dBA. An average Nirvana fan with a big system in their trailer in Humptulips can exceed 150dBA.
SPL (see Sound Pressure Level)
STEREO PAIRED
The placement of left and right channel controls directly next to each other for ease of dual adjustment. Most other ten-band equalizers separate left and right channels making the user perform two separate adjustments of each band and risking lack of imaging through misadjustment. Not to be confused with stereo-ganged, where one knob or slider controls both channels.
SUBSONIC
Technically, Subsonic refers to "Below the speed of sound". It is also often used in audio specifications to indicate a sound whose frequency is below the limit of human hearing. The proper term to use is Infrasonic.
TAPE MONITOR
A circuit which lets you add on accessories without disturbing the pre-amp to amp line levels. Since our equalizers hook onto this circuit, we provide another one to hook in more accessories or maybe even, perish the thought, a tape deck.
TCHEBYCHEV
The type of highpass filter circuit design we use on our subsonic switch. It provides a very sharp cutoff so the bass that you want to keep is not effected.
WARBLE TONE
An oscillating test tone which sweeps across a set bandwidth producing a flat signal when averaged by a meter with slow ballistics. AudioControl uses this type of test tone to create a very accurate analyzer in the Richter Scale.