Sound Recording Techniques
Fairies and space and castles and popcorn and buttercream layered cake
Terms in this set (195)
DIGITAL compact audio interface; transfers compressed/uncompressed DIGITAL audio data; compatible: computer monitor, digital television, digital audio device.
2 or more electrical conductors held together by an insulating jacket; can easily separate by simply pulling apart; use: speaker wire.
X-Y miking technique
microphone technique; two directional mics of same type placed with grills as close together as possible without touching; facing at angles to each other (90-135 degrees); midpoint of mic pointed towards the source; mic outputs equally panned L and R. Prevents phase problems.
style of audio connector; circular in design; 3 pins; use in BBBBBalanced line; female and male connectors
wow and flutter
happen on audio tape, cassette, vinyl, other analog recorders. Irregularities in the playback speed of analog recordings; wow is slower, flutter is faster.
loudspeaker driver; produces low frequency sounds; 40 htz +; Stiff paper cone + voice coil, surrounded by magnetic field; voice coil + magnet = linear electric motor. Sound waves created through in + out motion.
made of porous foam; fits over microphone; good for outdoors; help filter out high frequ. sounds.
a signal that contains equal power within any frequency band with a fixed width.
more calibrated to the way the human ear perceives sound; equal energy per OCTAVE (as opposed to per frequency).
the physical distance in a medium between the beginning and end of a cycle; sound travels at 1130ft/second.
waveform or timbre
visual model of the wave propagation of a sound wave in our physical environment; shows amplitude and frequency most commonly. These characteristics help us distinguish one waveform from another and therefore one timbre or sound from another. dull to bright, simple to complex.
unit of power measurement; electrical power delivered to the loudspeaker. One joule per second. Helpful for amplifier and loudspeaker power ratings.
voice coil size
small voice coil = less control over a cone; large voice coil = more efficient, cost and performance of speakers increase.
regular pulsing change of pitch
loudspeaker; high audio frequencies; 2,000 hz = 20,000 hz
produces a varying magnetic field, which works against the fixed magnetic field of a magnet around which the cylindrical voice coil is suspended, forcing the voice coil—and the diaphragm attached to it—to move. This mechanical movement exactly resembles the waveform of the electronic signal supplied from the amplifier's output to the voice coil. Since the coil is attached to a diaphragm, the vibratory motion of the voice coil transmits to the diaphragm; the diaphragm in turn vibrates the air — thus creating air motions or audio waves, which we hear as high sounds.
adjusting speakers in a specific way; reduces variations in frequency response; in sound recording studio; aim for flat frequ. response curve; equalize monitors OR change speaker settings.
variation in amplitude; rapid reiteration of a note; rapidly turning volume signal up and down.
MICROPHONE measurement; how quickly a mic's diaphragm reacts when hit by an acoustic wave; is the difference in sound quality among different mice.
high amplitude, short-duration sound at the beginning of a waveform; can contain a lot of non-periodic components, also more high frequ. than the harmonic content of the sound; do not necessarily depend on the frequ. of the tone they initiate.
separate "slots" in which new recordings can be set down and synchronized in the process of creating a cohesive song.
STUDIO ACOUSTICS; In a laboratory, specimens to be measured are placed between two rooms that are isolated from each other so there is no transmission of vibration. Often the rooms are supported on springs.The sketch shows an idealized facility for measuring wall sound transmission. Such facilities are also used for evaluating windows, doors and other elements that are built into walls. A facility for testing floors has one room above the other.
Note that in a laboratory test, the only path between rooms is through the wall or floor being tested. This is often not true in buildings.
Noise is generated in one room and the sound pressure levels in decibels are measured in both at several different frequencies. The bandwidth for the measurement is one-third of an octave. The difference in levels is corrected to account for the acoustical properties of the receiving room.
The quantity that results is the transmission loss in decibels (dB). This represents the loss in sound power due to transmission through the specimen. The higher the transmission loss, the less sound passes through the wall.
device that changes one form of energy into another; example: microphone; sound-pressure waves ===> electrical voltages. Example: recording device; electrical voltage ===> signals on magnetic tape or digital data.
threshold of pain
sound-pressure level of 140 db, between 200hz - 10khz frequency range; causes pain in average listener
threshold of feeling
SPL of 118 db, frequ. of 200 Hz - 10 Khz; causes discomfort in listener.
threshold of hearing
minimum SPL that produces hearing; SPL of 0 db
20,000 hz; not heard by human ear.
more front pickup and less rear pickup; figure-8 pattern; 5:3 ratio (front to rear).
sum and difference tones
psychoacoustic phenomena; two tones played simultaneously, listener perceives an additional tone whose frequency is the sum or difference of the two frequencies.
20 Hz; not heard by human ear.
conductors made of many fine metal filaments, twisted together to form a large thicker wire. More flexible but not very solid. Used in shorter network cables.
conductors made of solid metal (copper). Cable is more rigid because of the single thick copper wire; resistant to bending. Best use -- backbone cable runs through walls due where flexibility isn't required.
SPEAKERS; method of sound reproduction; creates illusion of directionality and audible perspective; uses two or more independent audio channels and speakers, played in various directions.
STUDIO ACOUSTICS; when sound is reflected off parallel surfaces and travels back on its own path; creates phase differences; interferes with room's frequency response. Sounds like: increasing/decreasing volume levels at various frequencies throughout the room area due to the phase cancellations and reinforcements.
Sound Pressure Level
MEASUREMENT; acoustic pressure that has built up within a defined atmospheric area. Higher SPL, louder the sound. Measured in db.
describes propagation of sound. Sound moves in a sphere of sound outwards from the source.
spectrum or realtime analyzer
laboratory instrument; displays signal amplitude by signal frequency on a graph. Frequency is x-axis, amplitude is y-axis. Used to find stray output signals. Connects to wireless receiver or computer.
Society of Motion Picture and Television Engineers; an international association that creates guidelines for production of media; includes SMPTE timecode.
a basic periodic audio waveform; like a building block.
signal to noise ratio
MEASUREMENT; compares level of desired signal to level of background noise.
MIC TECHNIQUES; when sounds such as "f", s, and sh are overly accentuated; results in tape saturation and high distortion levels; reduced by inserting a frequency-selective compressor into the chain or through moderate EQ.
the most highly directional; due to narrowness of sound, commonly used on television and film sets, in stadiums, and for field recordings on wildlife.
mechanical fastener that connects two parts elastically; helps reduce unwanted noise; isolates the mic from vibrations that might happen through a mic stand.
components are connected in a single path, so the same current flows through all the components; Speakers wired this way: increases impedance, decreases acoustical output
components are connected so that the same voltage is applied to each component. Speakers wired this way: impedance drops; the more speakers wired in, the lower the impedance, therefore amplifier power output rises, therefore raises acoustical output.
recording process; selectively using some record heads as playback heads so that new signals can be recorded on other tracks in perfect sync with the existing tracks. This dramatically changed the recording process, allowing overdubbing of individual recorded tracks.
AMPLIFIER; when input signal is so large that its DC output supply isn't large enough to produce corresponding output signal; causes distortion and clipping.
the resolution at which a recorded sound will be digitally captured.
a low frequency sound from the bearings inside a turntable. This is most noticeable in low quality turntables with ball bearings.
A frequency response which falls gradually above or below a
certain frequency limit.
"riding the gain" compression
turning the physical knob as your record music in order to compress the volume. You have to know that music ahead of time to predict when to turn the knob.
a microphone that uses electromagnetic induction; uses an extremely thin aluminum ribbon diaphragm; generates a small output signal, requires a transformer for decent output signal.
randomly decaying sets of sounds that can be heard after the source stops due to room reflections.
an example of this is the vibration induced in a violin or piano string of a given pitch when a musical note of the same pitch is sung or played nearby,
sound behaves much like a light wave; it reflects off a surface boundary at an angle that is equal to (and opposite in direction of) its initial angle of incidence.
consumer electronic component; home theatre system; amplifies sound from a multitude of possible audio sources.
a standardized frame for mounting multiple equipment modules.
low-frequ. phenomenon; occurs in directional mice; increase in bass response when mic is brought 1 foot within sound source; compensate with LF roll off filter switch.
a category of noise caused by contact transfer of signal patterns from one layer of tape to another.
pressure zone mic
omnidirectional; positioned near or on a surface; good piano mic; full-room sound pickup when mounted on wall; prevents phase interference in an ensemble.
when a sound on a recording is heard before it occurs. Most noticeable in percussive instruments. Due to print through.
when a sound on a recording is heard after it occurs; Due to print through.
electronic amplifier; boosts signal strength without degrading signal to noise ratio.
boosts audio output level to drive one or more loudspeakers at their rated volume levels. Problems: overloading transistors (impedance overload) ===> distortion ===> failure.
a knob responsible for changing the voltage.
any kind of porous or fibrous material such as textiles, fleece, carpets, foams, mineral wool, cotton wool and special acoustic plasters. They all absorb sound energy as they damp the oscillation of the air particles by friction.
an anti-pop noise protection filter for microphones, typically used in a recording studio.
a circular graph that shows how sensitive a microphone is in different directions.
the part of the cable that connects into something else; each cable has two plugs -- one end is female (like the part that connects into a computer CPU), the other end is male (like the part that connects into the wall).
Opposite of plug. You will always plug something into this.
computer software; adds to or enhances audio functionality in a computer program; digital signal processing or sound synthesis; usually provides user with their own interface.
carries digital audio and video signals; low cost, simple design; consumer electronic.
used for analog signals; older design (19th cent.)
an audio effect which takes advantage of the way sound waves interact with each other when they are out of phase. By splitting an audio signal into two signals and changing the relative phasing between them, a variety of interesting sweeping effects can be created.
a cycle of a waveform; the measure of TIME delays between two or more waveforms.
condesor mic that is powered directly from the console (like the computer). Supplies a + DC supply voltage of +48 V through both audio conductors to the condenser capsule and preamp.
MEASURING DEVICE read-out that measures the max amplitude fluctuations of a waveform
a driver without a voice coil and magnet assembly; a suspended cone not attached to a voice coil or electrical circuit; it is moved by internal air pressure produced by the movements of the active driver cone.
any of the sine waves by which a complex tone is described.
partials that are HIGHER than the fundamental frequency being played.
overtone frequencies that are whole-number multiples of the fundamental frequency.
happens if you push a speaker beyond its capabilities. instead of a smooth sine wave being produced for normal audio, a square waveform (clipped) will be outputted by the amplifier resulting in sound distortion.
recording new tracks in sync with previously recorded tracks.
an electronic circuit that produces a repetitive, oscillating electronic signal, often a sine wave or a square wave.
adj. describing sounds emanating from all directions.
unit of measurement for impedance or resistance; used for rating microphones; needed to match the output resistance of one device to the rated input resistance requirements of another device.
non-wole-number multiples or the fundamental partial.
solutions to reducing noise in a recording or playback situation. Noise is caused by acoustic/electronic weak links in the chain; or the medium itself is incapable of encoding a wide dynamic range and so a lot of distortion is created through overload.
Hearing direct sound means overall room acoustics don't matter that much. the placement of a small to medium-sized bookshelf speakers on each side of a desktop.
During multi-track editing with a music bed and voice-over, it is necessary sometimes to mute the music bed or the vo track in order to do video/audio alignment tasks. You dont always want to hear the whole mix when doing these.
MS miking technique
mid-side miking technique; two closely spaced mics (like X-Y); requires an external transformer or software plug-in to work. M mic picks up direct sound; the S mic picks up a figure 8 ambient sound. Plug-in or transformer edits them together. Combos include : M+S or M-S.
a device that helps critically evaluate a recording; like a computer or a sound board.
A speaker configuration where the sound is coming from one direction and one source (TV, radio, elevator).
miniature phone plug
a 1/4 inch connector; a plug widely used to connect mics and amplifiers.
device that boosts a mic signal to be processed by other equipment like mixing consoles and recording devices; ensures adequate quality.
a box or panel that has a face that is designed to vibrate or move with the sound pressure that is exerted upon it. works when sound pressure energy, especially lower frequency energy, strikes the front wall of the absorber.
the final mixdown of a project that has been fine-tuned with respect to relative balance between songs, dynamic level, equalization.
when the perception of one sound is affected by the presence of another sound. Gelfand provides a basic example. Let us say that for a given individual, the sound of a cat scratching a post in an otherwise quiet environment is first audible at a level of 10 dB SPL. However, in the presence of a masking noise (for example, a vacuum cleaner that is running simultaneously) that same individual cannot detect the sound of the cat scratching unless the level of the scratching sound is at least 26 dB SPL. We would say that the unmasked threshold for that individual for the target sound (i.e., the cat scratching) is 10 dB SPL, while the masked threshold is 26 dB SPL. The amount of masking is simply the difference between these two thresholds: 16 dB.
loudness contour circuit
employed in most audio devices which have a volume control. At low volume levels, the human auditory system is less sensitive to frequencies at the upper and lower ends of the audio band of frequencies. The contour INCREASES the level of the audio signal at those frequencies (where the ear's sensitivity is reduced) as the volume DECREASES. At the upper end of the volume control's range, the loudness contour has little or no effect.
relative and do not refer to specific volume levels.
duplicating a portion of an audio track and stringing these copies together.
are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave.
a moving wave that consists of oscillations occurring perpendicular (or right angled) to the direction of energy transfer. If a transverse wave is moving in the positive x-direction, its oscillations are in up and down directions that lie in the y-z plane.
Analog term; remains at a constant level, regardless of the current setting of the volume control. Recording equipment can be connected to this line without having to monitor it through the device's speaker, and without the loudness of the recording changing if the volume control setting of the device is modified whilst recording.
a processing device that is used to keep signal peaks from exceeding a certain level in order to prevent the overloading of amplifier signals, recorded signals onto tape or disc, broadcast transmission signals, and so on.
Proper audio levels are crucial. If the audio level is too high when recording, overload of the input electronics will cause audio distortion. If audio levels are too low, the signal-to-noise ratio deteriorates. Audio levels are typically indicated either by mechanical VU-meters or electronic LED bar graph meters.
the amplitude modulation of signals containing two or more different frequencies in a system with nonlinearities. The phenomenon between each frequency component will form additional signals at frequencies that are not just at harmonic frequencies (integer multiples) of either, but also at the sum and difference frequencies of the original frequencies and at multiples of those sum and difference frequencies.
an electronic device containing an audio preamplifier and power amplifier in one unit, as opposed to separating the two.
inner groove distortion
As you get nearer the center of the record, the groove velocity reduces (in fact the linear speed of the groove is about 1/3 of the speed in the centre that it is at the rim). It's like playing the start of your record at 15ips on tape and slowing it down to 3 3/4 by the end of the side. Basic frequency response is affected, due to the cut waveforms becoming shorter. In the limit, high frequencies become too small to move the stylus. A narrow stylus profile helps (though not as much as you'd think) as does accurate set-up (any error is more significant at the inner radius). Any friction in the arm will show more at the inner grooves too. Mechanical 'semi auto' features can cause a lot of problems.
Many 'classic' good sounding albums are programmed to have 'less challenging' tracks at the ends of sides. The playing field is more level with tapes and CD.
a way of enclosing a loudspeaker; to mount the loudspeaker driver in a very large sealed enclosure, providing minimal 'air spring' restoring force to the cone.
the measure of the opposition that a circuit presents to a current when a voltage is applied.
Ground loops are usually perceived as a hum or buzz in your audio signal. They generally emerge when an electrical system consisting of two or more electrical devices is connected to the electrical ground in multiple ways. If the ground of the different power sources does not have the same reference level, an equalizing current will run through the audio connection and intersperse to the audio signal.
a loudspeaker or loudspeaker element which uses a horn to increase the overall efficiency of the driving element(s).
the numbers of sound cycles that occur in a second.
The capacity of a system to reproduce loud sounds without distortion. Measured in db. the amount by which the signal-handling capabilities of an audio system exceed a designated level in db.
in general, echoes occurring within approximately 40ms of the direct sound become fused with the direct sound. We say that the echo becomes "one" with the direct sound, and only a loudness enhancement occurs. Fusion (and loudness enhancement) will occur even if the closely-timed echo comes from a different direction than the original source.
When two or more devices are connected to a common ground through different paths, ground path noise can result. Thus, a system grounded at two different points, with a potential difference between the two grounds can cause unwanted noise voltage in the circuit paths. Currents flow through these multiple paths and develop voltages which can cause damage, noise or 50Hz/60Hz hum in audio or video equipment.
a measurement of how large a wire is, either in diameter or cross sectional area.
a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output, by adding energy to the signal converted from some power supply.
the lowest frequency of a periodic waveform.
the charted output of an audio device. The curve represents how the device will response to the audio spectrum and, in turn, how it will effect the signal's overall sound.
the rate at which an acoustic generator, electrical signal, or vibrating mass repeats within a cycle of positive and negative amplitude. As the rate increases, so does the pitch.
A characteristic RESONANCE region. A musical instrument may have several formant regions dictated by the shape and resonance properties of the instrument. The human voice also has formant regions determined by the size and shape of the nasal, oral and pharyngeal cavities (i.e. the vocal tract), which permit the production of different VOWELs and voiced CONSONANTs.
a horn that is folded to create a longer path, allowing the fundamental more room to unfold.
a curve that indicates the ear's average sensitivity to different frequencies at various levels.
If the speaker has this type of response, it will stay true to the variations in level differences from the amplifier; i.e. the speaker does not alter the sound coming from the source, so it is more accurate but might sound more "stale" because it isn't adjusting to accommodate our ears.
a special kind of positive feedback which occurs when a sound loop exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a loudspeaker). In this example, a signal received by the microphone is amplified and passed out of the loudspeaker.
a method of constructing new data points within the range of a discrete set of known data points. In engineering and science, one often has a number of data points, obtained by sampling or experimentation, which represent the values of a function for a limited number of values of the independent variable. It is often required to estimate the value of that function for an intermediate value of the independent variable.
a frequency-discriminating amplifier; achieved through the use of resistor/capacitor networks that boost (amplify) or cut (attenuate) certain frequencies.
the process of adjusting the balance between frequency components within an electronic signal. Boosting or cutting the energy of specific frequency bands. the process commonly used to alter the frequency response of an audio system using linear filters."frequency-specific volume knobs."
characteristic variations in level that occur over the duration of a played note. Attack, decay, sustain, and release.
a class of electronic filter used in audio applications. Most individual loudspeaker drivers are incapable of covering the entire audio spectrum from low frequencies to high frequencies with acceptable relative volume and absence of distortion so most hi-fi speaker systems use a combination of multiple loudspeakers drivers, each catering to a different frequency band. Crossovers split the audio signal into separate frequency bands that can be separately routed to loudspeakers optimized for those bands.
disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source; creates hum and RF
the ratio of energy output to the total energy input expressed as a percentage.
a sound or series of sounds caused by the reflection of sound waves from a surface back to the listener.
A type of microphone. operates using electromagnetic induction to generate an output signal. Whenever an acoustic pressure wave hits the diagphragm's face, the attach voice coil is displaced in proportion to the amplitude and frequency of the wave.
the transfer or copying of previously recorded audio material from one medium to another of the same or a different type. It may be done with a machine designed for this purpose, or by connecting two different machines: one to play back and one to record the signal. The purpose of this action may be simply to make multiple copies of audio programs, or it may be done to preserve programs on old media which are deteriorating and may otherwise be lost.
consists of the sounds of a given location or space. Every location has distinct and subtle sounds created by its environment. wet - with ambience; dry - without
s a small loss of data in an audio or video file on tape or disk. can sometimes go unnoticed by the user if the size of the dropout is small. Error correction schemes can compensate for this by filling in data where gaps are detected.
an individual transducer that converts electrical energy to sound waves, typically as part of a loudspeaker, television, or other electronics device. an electroacoustic transducer that produces sound in response to an electrical audio signal input.
the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer.
dolby 5.1 surround
a speaker setup made of five full-range monitors that are positioned in a circular arc, with the speakers being placed at equal distances to the listener (at the center position).
1982; first consumer high quality surround sound system.
noise reduction system; a series of noise reduction systems developed by Dolby Laboratories for use in analog magnetic tape recording. The first was Dolby A, a professional broadband noise reduction for recording studios in 1966, but the best-known is Dolby B (introduced 1968), a sliding band system for the consumer marke
The fundamentals of natural sound travel uniformly in all directions — a piano, for example, distributes sound throughout a room. Our hearing favors speakers that reproduce sound in the same way. Wide-dispersion speakers sound more real because they too fill the room. Limited-dispersion speakers seem less realistic because they beam, or project sound into only one area.
direct current (DC)
the unidirectional flow of electric charge.
Digital output. Transmits two channels of digital audio through single, 3-pin XLR mic or line cable in a single direction; balancecd.
Digital output; transmits digital audio between consumer digital audio devices and their professional counterpoints; UNBALANCED, single-conducted phono connector.
digital output; most common use is in consumer audio equipment (via a "digital optical" socket), where it carries a digital audio stream from components such as CD and DVD players, DAT recorders, computers, and modern video game consoles, to an AV receiver that can decode two channels of uncompressed lossless PCM audio or compressed 5.1/7.1 surround sound such as Dolby Digital Plus or DTS-HD High Resolution Audio.
a digital output standard; a straight-forward, clutter-free digital interface connection between multitrack devices; format allows up to 56 channels of linearly encoded digital audio to be connected via a single, video-grade coaxial cable. Makes use of a serial data transmission format that's compatible with AES/EBU twin-channel protocol.
a commercially distributed computer file containing a media product such as a film or music album. The term contrasts this computer file with the physical copy (typically a DVD or Blu-ray Disc) with which the Digital Copy is usually offered as part of a bundle. It allows the disc's purchaser to create a single copy of the movie on a computer, and to view it on that computer's display or an external display (e.g. television) connected to that computer.
a process by which numeric representations of analog signals (in the form of voltage levels) are encoded, processed, stored, and reproduced over time through the use of a binary number system.
sound-waves spread at regular and predictable values; if a room in question is rectangular or if further sound-wave dispersion is desired, diffusers can be attached to the wall and ceiling boundaries to help break up the standing waves. Diffusers are acoustical boundaries that reflect the sound wave back at various angles that are wider than the original incident angle.
sound has the inherent ability to "move" around or through a physical coustic barrier; sound can bend around an object in a maner that reconstructs the signal back to its original form in both frequency and amplitude. Even if a signal is greatly impeded (ex. if it has to travel through a door), it nevertheless begins to reconstruct itself in wavelength and relative amplitude and begins to radiate outward as though it were a new point of origin.
this type of recording overwrites pre-existing data. Once new tracks are recorded over old, the old tracks cannot be retrieved.
In the maintenance of file systems, this word is a process that reduces the amount of fragmentation. It does this by physically organizing the contents of the mass storage device used to store files into the smallest number of contiguous regions (fragments).
a logarithmic scale that has been adopted to compress the measurements of sound-pressure-level (amplitude) into figures that are more manageable.
the decrease in amplitude when a vibrating force has been removed i
Noise-reduction system; a full-bandwidth compansion system that can provide between 20 and 30 db of noise reduction; because all signals are compressed and expanded at a 2:1 ratio, the system isn't overly sensitive to variations in level (although it can be sensitive to frequency calibrations).
gives the ratio of the rated impedance of the loudspeaker to the source impedance. Only the resistive part of the loudspeaker impedance is used. The amplifier output impedance is also assumed to be totally resistive. In loudspeaker systems, the value of the damping factor between a particular loudspeaker and a particular amplifier describes the ability of the amplifier to control undesirable movement of the speaker cone near the resonant frequency of the speaker system. It is usually used in the context of low-frequency driver behavior, and especially so in the case of electrodynamic drivers, which use a magnetic motor to generate the forces which move the diaphragm. It is generally (though not universally) thought that tighter control of voice coil motion is desirable, as it is believed to contribute to better-quality sound. A high damping factor indicates that an amplifier will have greater control over the movement of the speaker cone, particularly in the bass region near the resonant frequency of the driver's mechanical resonance. However, the damping factor at any particular frequency will vary, since driver voice coils are complex impedances whose values vary with frequency.
any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. usually caused by undesired capacitive, inductive, or conductive coupling from one circuit, part of a circuit, or channel, to another.
because individual speaker elements (drivers) are more efficient in some frequency ranges than others, different driver sizes and types are often used in combination to give the desired frequency response and level output.
the spread of a sound signal (either monaural or stereophonic pairs) into a new stereo or multi-channel sound field. A typical physical recording console pan control is a knob with a pointer which can be placed from the 8 o'clock dial position fully left to the 4 o'clock position fully right. Audio mixing software replaces the knob with an on-screen "virtual knob" or slider for each audio source track which functions identically to its counterpart on a physical mix console.
The control knob is designed to distribute its source sounds with constant power, so that at the full left extreme, with the knob pointing to the 8 o'clock position, the sound appears in only the left channel, with all the energy going exclusively to the left channel (speaker). Conversely, when placed in the far right extreme, that is the 4 o'clock position, the sound only appears in the right. In the middle, at the 12 noon position, the sound in each channel is evenly distributed, but decreased in each channel by the law amount, thereby distributing the left and right energy equally across the two output channels, so that the overall sound power level is always constant regardless of the knob position.
a phenomenon in which two waves superimpose to form a resultant wave of greater or lower amplitude.
Condenser means capacitor, an electronic component which stores energy in the form of an electrostatic field. The term condenser is actually obsolete but has stuck as the name for this type of microphone, which uses a capacitor to convert acoustical energy into electrical energy.
Condenser microphones require power from a battery or external source. The resulting audio signal is stronger signal than that from a dynamic. Condensers also tend to be more sensitive and responsive than dynamics, making them well-suited to capturing subtle nuances in a sound. They are not ideal for high-volume work, as their sensitivity makes them prone to distort. A capacitor has two plates with a voltage between them. In the condenser mic, one of these plates is made of very light material and acts as the diaphragm. The diaphragm vibrates when struck by sound waves, changing the distance between the two plates and therefore changing the capacitance. Specifically, when the plates are closer together, capacitance increases and a charge current occurs. When the plates are further apart, capacitance decreases and a discharge current occurs.
A voltage is required across the capacitor for this to work. This voltage is supplied either by a battery in the mic or by external phantom power.
can be thought of as an automatic fader; it is used to propotionately reduce the dynamics of a signal that rises above a user-definable level to a lesser volume range; this process is done so that the dynamics can be managed by the electronics and/or amplifiers in the signal chain; the range is appropriate to the overall dynamic of a playback or broadcast medium; an instrument better matches the dynamics of other recorded tracks within a song or audio program.
allows signals with a large dynamic range to be transmitted over facilities that have a smaller dynamic range capability. employed in telephony and other audio applications such as professional wireless microphones and analog recording. The dynamic range of a signal is compressed before transmission and is expanded to the original value at the receiver.
a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a radio frequency transmission line.
the mic is positioned about 1 inch to 3 feet from a sound source; commonly used technique; yields two results: a tight present sound quality, and excludes the acoustic environment.
a mild to severe waveform distortion effect that happens when an amplifier is saturated.
by combining two identical (and often slightly delayed) signals that are slightly detuned in pitch from one another, this effect is created. It's also an effects tool that creates depth, richness, and harmonic structure to their sound.
a communications channel in a storage device, used in operations such as multi-track recording and playback. Modern recordings typically incorporate two audio channels, although sound recording began with a single channel and other amounts have been used.
a type of directional pattern; heart-shaped; the diaphragm receives two signals: the incident signal, from the front, and the acoustically delayed rear signal.
when two waves that are out of phase interfere and destroy or reduce each other.
the practice of using two audio amplifier channels to power a loudspeaker with multiple drivers.It differs from the conventional arrangement in which each channel of amplification powers a complete speaker. typically consists of a crossover network and two or more drivers.
Two tones that differ only slightly in frequency and have approximately the same amplitude will produce this effect. Sounds like repetitive volume surges that are equal in frequency to the difference between these two tones.
a type of loudspeaker enclosure that uses the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical closed box loudspeaker or an infinite baffle mounting.
uses three wires to properly carry the audio signal. Two of the wires are used to carry the signal voltage, while a third lead is used as a neutral ground wire. Since neither of the two signal conductors of a balanced line is directly connected to the signal ground, the alternating current of an audio signal will travel along the two independent wires. Since the input of a balanced device will only respond to the alternating voltage potentials between the two leads, the unwanted noise will be cancelled.
high-impedance mics and most line-level instrument lines use this type of line to transmit signals from one device to another. In an unbalanced circuit, a single signal lead carries a positive current potential to a device, while a second, grounded shield is used to complete the circuit's return path. When working at low signal levels, any noises, hums, buzzes, or other types of interference that are induced into the signal path will be amplified along with the input signal.
a sound-isolating panel. Used in stereos and recording studios.
playing sound backwards.
an overtone that is heard by the normal ear when a pure tone of suitable frequency and intensity is sounded and that is presumably due to the nonlinear response of the ear mechanism
a temporary loss of hearing after exposure to sound.
a periodic vibration whose frequency is audible to the average human. It is the property of sound that most determines pitch and is measured in hertz (Hz).
an electronic device that reduces the power of a signal without appreciably distorting its waveform. effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1.
refers to the time taken for a sound to build up to its full volume when a note is initially sounded.
a technique used for the recording of analog signals which among many possibilities include audio frequency, analog audio and analog video information for later playback.
the objective measurement of the degree of change (positive or negative) in atmospheric pressure (the compression and rarefaction of air molecules) caused by sound waves.
this setup of miking set up places the pickup at such a distance that the reverberant or room sound is equally or more prominent than the direct signal.
the flow of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge is only in one direction.
Transistors also have a predictable response to a given voltage, but that response can be changed by tuning the gate voltage in order to open or close the conducting channel. Effectively, the transistor can be in one of two states:
Functioning like a wire with a small resistance, passing most current through while dissipating a small amount of heat.
Functioning like an insulator with a high resistance, blocking most current and dissipating more heat.
1. Functioning like a wire with a small resistance, passing most current through while dissipating a small amount of heat.
Functioning like an insulator with a high resistance, blocking most current and dissipating more heat.
The controlling gate which allows us to pick between these two states can actually add energy to the system, increasing the current output, thus the transistor is called an ________ ________.
Resistors, capacitors, and inductors respond in a reliable way to any applied voltage that induces an electric field. Resistors dissipate heat, capacitors store charge, and inductors store magnetic flux. These responses always occur and cannot be manipulated without manipulating the very structure of the material which causes the response. They don't add energy or electrons to a circuit, but merely redirect the electrons provided by an external source. Thus these are called ______________.
a type of loudspeaker that reduces bass distortion caused by non-linear, stiff mechanical suspensions in conventional loudspeakers.
effectively, the inverse of reflection. An important factor in studio acoustics. Whenever sound strikes a material, the amount of acoustic energy that's absorbed relative to the amount that's reflected is expressed in an absorption ratio.