A. Signal-Based Terms

I. Clipping

Clipping is a form of distortion where the amplitude of a signal is too powerful for the medium transmitting it. This could be a cable, a vacuum tube, or a digital device's internal resolution. Looking at the resulting waveform, it appears that the peaks of the signal are "clipped" off. Different devices clip differently, and while some forms of clipping are desirable (most often tube clipping), others are usually undesirable (cables or digital clipping).

Ii. Distortion

Any transformation of a signal can technically be called distortion. For guitars, it usually refers to a specific, desired transformation - the sound of vacuum tube clipping, even if these are emulations by solid state analog devices like stomp boxes, or created by digital algorithms in modelers.

Iii. Signal

A signal is the physical embodiment of information communicated from one device to another. In guitar terminology, this usually means the strings inducing electric potentials in guitar pickups, which are passed on through cables into amplifiers, then into speakers where it is converted to sound and sent to the audience's ears. The signal is the message desired to be communicated. Hum, noise, and other interference are generally not considered the signal. In fact, they are considered to degrade the signal.

Iv. Noise

Noise is essentially randomness in the signal. Being chaotic, noise transmits little information, other than that it is noise. Whereas a signal indicates timbre, pitch, and harmony, noise does not convey any of these qualities. The timbre of a guitar can change based on playing style, string gauge, pickups, woods, build quality...noise is always noise.

V. Signal-to-Noise Ratio (SNR)

A measure of the noticeability of the signal compared to the noticeability of noise. The higher the ratio, the "cleaner" and more "high fidelity" the sound.

Vi. Impedance

Electrical resistance to an alternating current. Direct current circuits amount of current is limited by the voltage of the power source and the resistance of the circuit. Similarly, impedance determines the amount of current flowing in an alternating current. Where the two concepts are fundamentally different is that impedance is variable depending on frequency. Normally, devices will have a resonant frequency where the impedance is least around a certain frequency, allowing a stronger flow of current at that frequency, while frequencies above the resonant frequency has increasingly high impedance and roll-off high frequencies.

Vii. Signal Chain

A signal chain is simply the ordered list of each device that affects the signal from its point of origin (the guitarist/guitar) until it is turned into sound waves. Typically displayed as text with arrows between each piece of the chain, showing the direction of the signal as it is transformed. For example: Ibanez guitar with Dimarzio Pickups > Ibanez Tube Screamer stomp box > MXR Flanger > Marshall JCM-800 amplifier > Marshall 1968 4x12 cab with Celestion T-75 speakers

Viii. Mono

Refers to a single, independent signal. Most simple guitar signal chains are mono - the guitar is generating a single signal from a single pickup (or two pickups wired together), going through a single cable into a single amplifier input, into a single speaker cabinet. Any device that has a single input and output is said to be mono.

Ix. Stereo

Stereo refers to two independent signals operating in parallel. Most home stereos systems are called stereos because they output two independent signals through a pair of speakers. And these are often arranged to the left and right of the listener. In guitar terms, the stereo signals originate from a single point - the guitar, even if the guitar outputs from two independent pickups, such as a piezo and a magnetic (or 2 independent magnetics). Also, the signals are often sent to the same or similar devices designed to process both signals. Thus, the two signals are often referred to as a single stereo signal. Most often, stereo signals don't come into play until an amplifier's fx loop, where a mono signal is sent to a stereo fx unit where it is split, processed differently for each signal and output as a stereo signal. The amp then will amplify each signal independently and send them to two different cabs. Or a mono single is split and sent to two amps. Or as previously mentioned the guitar itself outputs stereo from 2 different pickups.

X. Field

For a stereo signal, one of the two independent signals is often called a field. So every stereo signal has two fields, usually called a left and right field.

Xi. Balance

In reference to a stereo signal, balance refers to the relative volume of the left vs. right fields. Turning the balance all the way to the left would completely mute the right field.

Xii. Pan

Pan refers to the proportion of how a signal is routed into the left or right field of a stereo signal. For example, if you have mono guitar signal in a mixer or DAW, panning center means the signal is equally audible in both the left and right fields. Panning full left would mean the signal is just as loud in the left field as when panned center but is muted in the right field. Occasionally, a pan control will be applied to a stereo input signal, and in this case, the center setting will retain the original balance, but panning left or right will push both fields into either the left or right field.

Notice the difference between balance and pan. Balance operates by adjusting the relative volume of each field of a stereo signal. Panning "pushes" a signal into one field or the other or both.

B. EQ-Based Terms

Date: 2016-01-03; view: 774