Fader

A fader is a variable attenuator or potentiometer, used to control various parameters, from volume to cutting or boosting certain frequencies. The name comes from “fade out”, the process of gradually decreasing the volume of a signal source down to complete silence. Unlike rotative potentiometers, faders move up and down in a straight line and are used mostly in mixing consoles (volume faders) and graphic equalizers. Faders are handy specially in graphic EQ's because they also offer a good visual representation of the envelope curve.

Feedback

Feedback is best described as a signal coming from a source being fed back to the initial input and then processed once more. In audio industry, feedback could be most easily described as one live microphone picking up the sound from a close loudspeaker and routing it back in the same amplification circuit, thus creating a loop. Feedback adds the additional signal to the original source and if gotten out of control, it ends up in suppressing the original sound and letting only the back-fed audio cycle through the loop, creating the much-hated “squeal” on certain frequencies. Yet, feedback can be creatively used when controlled sufficiently; guitar distortion and skillfully -controlled feedback has made a tremendous career in rock/metal playing techniques.

Feedback Eliminator

The feedback eliminator is an electronic device that has gained serious popularity in the last 15 years, once with the technological advance in the field. Roughly, the feedback eliminator is a piece of gear capable of detecting the frequency of your feedback “squeal” and then finely-tuning a specialized electronic, EQ with a very narrow bandwidth on that frequency, cutting it down until the phenomenon disappears. One must note that an effective feedback eliminator works in milliseconds so that it will actually prevent the “squeal” from being heard; otherwise it is useless. This is the exact goal of the feedback eliminator and this is why it is used mostly in live situations and studios.

Ferrofluid

Ferrofluidul este un compus lichid sintetic cu excelente proprietati de racire si care ofera in acelasi timp o buna lubrefiere. Ferrofluidul este utilizat in componenta unor disfuzoare, fiind injectat in spatiul dintre bobina difuzorului si magnetul permanent, preintampinand supraincalzire si in cele din urma, griparea/distrugerea structurii motoare. Ferrofluidul s-a dovedit a fi una din cele mai performante tehnologii pentru mentinerea difuzoarelor la temperaturi operationale chiar si in cazul in care difuzoarele sunt supuse unor puteri mari timp indelungat.

Flanger

The flanger is an effect heavily used by both players and music producers and it consists of mixing the original sound with a processed version, ran through a delay unit with a delay time under 20 milliseconds, with gradually changing amount. This creates a sweeping effect, also known as “comb filter” and can result in a more interesting and creative-friendly sound when a part of the signal is fed back to the whole circuit. Flanger can be used with vocals, pianos, drums and pretty much any instrument, adding an interesting coloration to the overall sound.

Flat response

The flat response of an audio equipment is considered to be linked with the lack of coloration; this means that as a flat input is used, the outcome of the respective equipment will be also flat, without boosting or cutting certain frequencies and all of them are reproduced at equal levels. In sound production, especially in mixing and mastering stages, it is widely accepted that if a track sounds well on a flat system it will also do well on the end listener's equipment. For example, studio monitors are especially designed to sport a flat response without cabinet coloration; production chambers are acoustically damped so no wall-reflections alter the sound perceived by the sound engineer.

Focal length

The focal length of an objective represents the distance between the optical center of the objective and the surface of the sensor within the device, when the objective is set for infinity. The inscription on the objective, usually in mm, indicates the minimal focal length, meaning the minimal distance between the optical center of the objective and the plane of the sensor. Taking into account the fact that only the central part of an image formed by the objective can meet satisfactory qualities, this part has been called the image span and may be represented by a circle in which the image projected by an objective forms.

FOH

FOH is an acronym for Front Of House and is a term used in PA-related discussions to denote the equipment placed in the audience area, most of the times the large loudspeaker stacks enforcing the sound to a certain event. When referring to FOH, this generally means pretty much anything having to do with the main sound and its operational environment, from mixer to cabling and many more.

Front Loading

Front loading or front loaded describes the manner in which drivers are mounted in loudspeakers and cabinets, meaning that they are affixed to the front of the respective cabinet – the front baffle. The front loading is met throughout most speakers and studio monitors, bass an guitar combos and cabs. The front loading is the opposite for horn loading.

Full duplex

Full duplex referst to a system or channel to relay data in both directions simultaneously. Coming initially from telecommunications, the full duplex has quickly entered audio industry and the best example are the full duplex audio cards, able to record and play back data.

Full range

When used in connection with loudspeakers, the full range determines that a speaker can reproduce sound between the commonly accepted human hearing limits: 20Hz for the bass and 20kHz for the treble. The full range capability is not linked to flat response and cannot be used describing, let's say, a loudspeaker that goes from 20Hz to 16kHz or from 30Hz to 30kHz.