The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a power or field quantity to another on a logarithmic scale, the logarithmic quantity being called the power level or field level, respectively. It can be used to express a change in value (e.g., +1 dB or −1 dB) or an absolute value. In the latter case, it expresses the ratio of a value to a fixed reference value; when used in this way, a suffix that indicates the reference value is often appended to the decibel symbol. For example, if the reference value is 1 volt, then the suffix is "V" (e.g., "20 dBV"), and if the reference value is one milliwatt, then the suffix is "m" (e.g., "20 dBm").^{[1]}
Two different scales are used when expressing a ratio in decibels, depending on the nature of the quantities: power and field (rootpower). When expressing a power ratio, the number of decibels is ten times its logarithm to base 10.^{[2]} That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing field (rootpower) quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two so that the related power and field levels change by the same number of decibels in, for example, resistive loads.
The definition of the decibel is based on the measurement of power in telephony of the early 20th century in the Bell System in the United States. One decibel is one tenth (deci) of one bel, named in honor of Alexander Graham Bell; however, the bel is seldom used. Today, the decibel is used for a wide variety of measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signaltonoise ratios are often expressed in decibels.
In the International System of Quantities, the decibel is defined as a unit of measurement for quantities of type level or level difference, which are defined as the logarithm of the ratio of power or fieldtype quantities.^{[3]}
dB  Power ratio  Amplitude ratio  

100  10000000000  100000  
90  1000000000  31623  
80  100000000  10000  
70  10000000  3162  
60  1000000  1000  
50  100000  316  .2  
40  10000  100  
30  1000  31  .62  
20  100  10  
10  10  3  .162  
6  3  .981 ≈ 4  1  .995 ≈ 2 
3  1  .995 ≈ 2  1  .413 ≈ √2 
1  1  .259  1  .122 
0  1  1  
−1  0  .794  0  .891 
−3  0  .501 ≈ ^{1}⁄_{2}  0  .708 ≈ √^{1}⁄_{2} 
−6  0  .251 ≈ ^{1}⁄_{4}  0  .501 ≈ ^{1}⁄_{2} 
−10  0  .1  0  .3162 
−20  0  .01  0  .1 
−30  0  .001  0  .03162 
−40  0  .0001  0  .01 
−50  0  .00001  0  .003162 
−60  0  .000001  0  .001 
−70  0  .0000001  0  .0003162 
−80  0  .00000001  0  .0001 
−90  0  .000000001  0  .00003162 
−100  0  .0000000001  0  .00001 
An example scale showing power ratios x, amplitude ratios √x, and dB equivalents 10 log_{10} x. 
The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. The unit for loss was originally Miles of Standard Cable (MSC). 1 MSC corresponded to the loss of power over a 1 mile (approximately 1.6 km) length of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to the average listener. The standard telephone cable implied was "a cable having uniformly distributed resistance of 88 Ohms per loopmile and uniformly distributed shunt capacitance of 0.054 microfarads per mile" (approximately corresponding to 19 gauge wire).^{[4]}
In 1924, Bell Telephone Laboratories received favorable response to a new unit definition among members of the International Advisory Committee on Long Distance Telephony in Europe and replaced the MSC with the Transmission Unit (TU). 1 TU was defined such that the number of TUs was ten times the base10 logarithm of the ratio of measured power to a reference power.^{[5]} The definition was conveniently chosen such that 1 TU approximated 1 MSC; specifically, 1 MSC was 1.056 TU. In 1928, the Bell system renamed the TU into the decibel,^{[6]} being one tenth of a newly defined unit for the base10 logarithm of the power ratio. It was named the bel, in honor of the telecommunications pioneer Alexander Graham Bell.^{[7]} The bel is seldom used, as the decibel was the proposed working unit.^{[8]}
The naming and early definition of the decibel is described in the NBS Standard's Yearbook of 1931:^{[9]}
Since the earliest days of the telephone, the need for a unit in which to measure the transmission efficiency of telephone facilities has been recognized. The introduction of cable in 1896 afforded a stable basis for a convenient unit and the "mile of standard" cable came into general use shortly thereafter. This unit was employed up to 1923 when a new unit was adopted as being more suitable for modern telephone work. The new transmission unit is widely used among the foreign telephone organizations and recently it was termed the "decibel" at the suggestion of the International Advisory Committee on Long Distance Telephony.
The decibel may be defined by the statement that two amounts of power differ by 1 decibel when they are in the ratio of 10^{0.1} and any two amounts of power differ by N decibels when they are in the ratio of 10^{N(0.1)}. The number of transmission units expressing the ratio of any two powers is therefore ten times the common logarithm of that ratio. This method of designating the gain or loss of power in telephone circuits permits direct addition or subtraction of the units expressing the efficiency of different parts of the circuit ...
In 1954, J. W. Horton argued that the use of the decibel as a unit for quantities other than transmission loss led to confusion, and suggested the name 'logit' for "standard magnitudes which combine by addition".^{[10]}
In April 2003, the International Committee for Weights and Measures (CIPM) considered a recommendation for the inclusion of the decibel in the International System of Units (SI), but decided against the proposal.^{[11]} However, the decibel is recognized by other international bodies such as the International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO).^{[12]} The IEC permits the use of the decibel with field quantities as well as power and this recommendation is followed by many national standards bodies, such as NIST, which justifies the use of the decibel for voltage ratios.^{[13]} The term field quantity is deprecated by ISO 800001, which favors rootpower. In spite of their widespread use, suffixes (such as in dBA or dBV) are not recognized by the IEC or ISO.
ISO 800003 describes definitions for quantities and units of space and time. The decibel for use in acoustics is defined in ISO 800008. The major difference from the article below is that for acoustics the decibel has no absolute value.
The ISO Standard 800003:2006 defines the following quantities. The decibel (dB) is onetenth of a bel: 1 dB = 0.1 B. The bel (B) is ^{1}⁄_{2} ln(10) nepers: 1 B = ^{1}⁄_{2} ln(10) Np. The neper is the change in the level of a field quantity when the field quantity changes by a factor of e, that is 1 Np = ln(e) = 1, thereby relating all of the units as nondimensional natural log of fieldquantity ratios, 1 dB = 0.11513… Np = 0.11513…. Finally, the level of a quantity is the logarithm of the ratio of the value of that quantity to a reference value of the same kind of quantity.
Therefore, the bel represents the logarithm of a ratio between two power quantities of 10:1, or the logarithm of a ratio between two field quantities of √10:1.^{[14]}
Two signals whose levels differ by one decibel have a power ratio of 10^{1/10}, which is approximately 1.25893, and an amplitude (field quantity) ratio of 10^{1⁄20} (1.12202).^{[15]}^{[16]}
The bel is rarely used either without a prefix or with SI unit prefixes other than deci; it is preferred, for example, to use hundredths of a decibel rather than millibels. Thus, five onethousandths of a bel would normally be written '0.05 dB', and not '5 mB'.^{[17]}
The method of expressing a ratio as a level in decibels depends on whether the measured property is a power quantity or a rootpower quantity; see Field, power, and rootpower quantities for details.
When referring to measurements of power quantities, a ratio can be expressed as a level in decibels by evaluating ten times the base10 logarithm of the ratio of the measured quantity to reference value. Thus, the ratio of P (measured power) to P_{0} (reference power) is represented by L_{P}, that ratio expressed in decibels,^{[18]} which is calculated using the formula:^{[3]}
The base10 logarithm of the ratio of the two power quantities is the number of bels. The number of decibels is ten times the number of bels (equivalently, a decibel is onetenth of a bel). P and P_{0} must measure the same type of quantity, and have the same units before calculating the ratio. If P = P_{0} in the above equation, then L_{P} = 0. If P is greater than P_{0} then L_{P} is positive; if P is less than P_{0} then L_{P} is negative.
Rearranging the above equation gives the following formula for P in terms of P_{0} and L_{P}:
When referring to measurements of field quantities, it is usual to consider the ratio of the squares of F (measured field) and F_{0} (reference field). This is because in most applications power is proportional to the square of field, and historically their definitions were formulated to give the same value for relative ratios in such typical cases. Thus, the following definition is used:
The formula may be rearranged to give
Similarly, in electrical circuits, dissipated power is typically proportional to the square of voltage or current when the impedance is constant. Taking voltage as an example, this leads to the equation for power gain level L_{G}:
where V_{out} is the rootmeansquare (rms) output voltage, V_{in} is the rms input voltage. A similar formula holds for current.
The term rootpower quantity is introduced by ISO Standard 800001:2009 as a substitute of field quantity. The term field quantity is deprecated by that standard.
Although power and field quantities are different quantities, their respective levels are historically measured in the same units, typically decibels. A factor of 2 is introduced to make changes in the respective levels match under restricted conditions such as when the medium is linear and the same waveform is under consideration with changes in amplitude, or the medium impedance is linear and independent of both frequency and time. This relies on the relationship
holding.^{[19]} In a nonlinear system, this relationship does not hold by the definition of linearity. However, even in a linear system in which the power quantity is the product of two linearly related quantities (e.g. voltage and current), if the impedance is frequency or timedependent, this relationship does not hold in general, for example if the energy spectrum of the waveform changes.
For differences in level, the required relationship is relaxed from that above to one of proportionality (i.e., the reference quantities P_{0} and F_{0} need not be related), or equivalently,
must hold to allow the power level difference to be equal to the field level difference from power P_{1} and V_{1} to P_{2} and V_{2}. An example might be an amplifier with unity voltage gain independent of load and frequency driving a load with a frequencydependent impedance: the relative voltage gain of the amplifier is always 0 dB, but the power gain depends on the changing spectral composition of the waveform being amplified. Frequencydependent impedances may be analyzed by considering the quantities power spectral density and the associated field quantities via the Fourier transform, which allows elimination of the frequency dependence in the analysis by analyzing the system at each frequency independently.
Since logarithm differences measured in these units are used to represent power ratios and field ratios, the values of the ratios represented by each unit are also included in the table.
Unit  In decibels  In bels  In nepers  Power ratio  Field ratio 

1 dB  1 dB  0.1 B  0.11513 Np  10^{1⁄10} ≈ 1.25893  10^{1⁄20} ≈ 1.12202 
1 Np  8.68589 dB  0.868589 B  1 Np  e^{2} ≈ 7.38906  e ≈ 2.71828 
1 B  10 dB  1 B  1.1513 Np  10  10^{1⁄2} ≈ 3.16228 
The unit dBW is often used to denote a ratio for which the reference is 1 W, and similarly dBm for a 1 mW reference point.
(31.62 V / 1 V)^{2} ≈ 1 kW / 1 W, illustrating the consequence from the definitions above that L_{G} has the same value, 30 dB, regardless of whether it is obtained from powers or from amplitudes, provided that in the specific system being considered power ratios are equal to amplitude ratios squared.
A change in power ratio by a factor of 10 corresponds to a change in level of 10 dB. A change in power ratio by a factor of 2 or ^{1}⁄_{2} is approximately a change of 3 dB. More precisely, the change is ±3.0103 dB, but this is almost universally rounded to "3 dB" in technical writing. This implies an increase in voltage by a factor of √2 ≈ 1.4142. Likewise, a doubling or halving of the voltage, and quadrupling or quartering of the power, is commonly described as "6 dB" rather than ±6.0206 dB.
Should it be necessary to make the distinction, the number of decibels is written with additional significant figures. 3.000 dB is a power ratio of 10^{3⁄10}, or 1.9953, about 0.24% different from exactly 2, and a voltage ratio of 1.4125, 0.12% different from exactly √2. Similarly, an increase of 6.000 dB is the power ratio is 10^{6⁄10} ≈ 3.9811, about 0.5% different from 4.
The decibel is useful for representing large ratios and for simplifying representation of multiplied effects such as attenuation from multiple sources along a signal chain. Its application in systems with additive effects is less intuitive.
The logarithmic scale nature of the decibel means that a very large range of ratios can be represented by a convenient number, in a manner similar to scientific notation. This allows one to clearly visualize huge changes of some quantity. See Bode plot and Semilog plot. For example, 120 dB SPL may be clearer than "a trillion times more intense than the threshold of hearing".
Level values in decibels can be added instead of multiplying the underlying power values, which means that the overall gain of a multicomponent system, such as a series of amplifier stages, can be calculated by summing the gains in decibels of the individual components, rather than multiply the amplification factors; that is, log(A × B × C) = log(A) + log(B) + log(C). Practically, this means that, armed only with the knowledge that 1 dB is a power gain of approximately 26%, 3 dB is approximately 2× power gain, and 10 dB is 10× power gain, it is possible to determine the power ratio of a system from the gain in dB with only simple addition and multiplication. For example:
However, according to its critics, the decibel creates confusion, obscures reasoning, is more related to the era of slide rules than to modern digital processing, and is cumbersome and difficult to interpret.^{[20]}
According to Mitschke,^{[21]} "The advantage of using a logarithmic measure is that in a transmission chain, there are many elements concatenated, and each has its own gain or attenuation. To obtain the total, addition of decibel values is much more convenient than multiplication of the individual factors." However, for the same reason that humans excel at additive operation over multiplication, decibels are awkward in inherently additive operations:^{[22]} "if two machines each individually produce a sound pressure level of, say, 90 dB at a certain point, then when both are operating together we should expect the combined sound pressure level to increase to 93 dB, but certainly not to 180 dB!"; "suppose that the noise from a machine is measured (including the contribution of background noise) and found to be 87 dBA but when the machine is switched off the background noise alone is measured as 83 dBA. [...] the machine noise [level (alone)] may be obtained by 'subtracting' the 83 dBA background noise from the combined level of 87 dBA; i.e., 84.8 dBA."; "in order to find a representative value of the sound level in a room a number of measurements are taken at different positions within the room, and an average value is calculated. [...] Compare the logarithmic and arithmetic averages of [...] 70 dB and 90 dB: logarithmic average = 87 dB; arithmetic average = 80 dB."
Addition on a logarithmic scale is called logarithmic addition, and can be defined by taking exponentials to convert to a linear scale, adding there, and then taking logarithms to return. For example, where operations on decibels are logarithmic addition/subtraction and logarithmic multiplication/division, while operations on the linear scale are the usual operations:
Note that the logarithmic mean is obtained from the logarithmic sum by subtracting , since logarithmic division is linear subtraction.
Quantities in decibels are not necessarily additive,^{[23]}^{[24]} thus being "of unacceptable form for use in dimensional analysis".^{[25]}
The human perception of the intensity of sound and light approximates the logarithm of intensity rather than a linear relationship (Weber–Fechner law), making the dB scale a useful measure.^{[26]}^{[27]}^{[28]}^{[29]}^{[30]}^{[31]}
The decibel is commonly used in acoustics as a unit of sound pressure level. The reference pressure for sound in air is set at the typical threshold of perception of an average human and there are common comparisons used to illustrate different levels of sound pressure. Sound pressure is a field quantity, therefore the field version of the unit definition is used:
where p_{rms} is the root mean square of the measured sound pressure and p_{ref} is the standard reference sound pressure of 20 micropascals in air or 1 micropascal in water.^{[32]}
Use of the decibel in underwater acoustics leads to confusion, in part because of this difference in reference value.^{[33]}
The human ear has a large dynamic range in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is greater than or equal to 1 trillion (10^{12}).^{[34]} Such large measurement ranges are conveniently expressed in logarithmic scale: the base10 logarithm of 10^{12} is 12, which is expressed as a sound pressure level of 120 dB re 20 μPa.
Since the human ear is not equally sensitive to all sound frequencies, noise levels at maximum human sensitivity, somewhere between 2 and 4 kHz, are factored more heavily into some measurements using frequency weighting. (See also Stevens' power law.)
The main instrument used for measuring sound levels in the environment and in the workplace is the Sound Level Meter. Most sound level meters provide readings in A, C, and Zweighted decibels and must meet international standards such as IEC 616722013.
According to Hickling, "Decibels are a useless affectation, which is impeding the development of noise control as an engineering discipline."^{[20]}
In electronics, the decibel is often used to express power or amplitude ratios (as for gains) in preference to arithmetic ratios or percentages. One advantage is that the total decibel gain of a series of components (such as amplifiers and attenuators) can be calculated simply by summing the decibel gains of the individual components. Similarly, in telecommunications, decibels denote signal gain or loss from a transmitter to a receiver through some medium (free space, waveguide, coaxial cable, fiber optics, etc.) using a link budget.
The decibel unit can also be combined with a reference level, often indicated via a suffix, to create an absolute unit of electric power. For example, it can be combined with "m" for "milliwatt" to produce the "dBm". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW).
In professional audio specifications, a popular unit is the dBu. This is relative to the root mean square voltage which delivers 1 mW (0 dBm) into a 600ohm resistor, or √1 mW×600 Ω ≈ 0.775 V_{RMS}. When used in a 600ohm circuit (historically, the standard reference impedance in telephone circuits), dBu and dBm are identical.
In an optical link, if a known amount of optical power, in dBm (referenced to 1 mW), is launched into a fiber, and the losses, in dB (decibels), of each component (e.g., connectors, splices, and lengths of fiber) are known, the overall link loss may be quickly calculated by addition and subtraction of decibel quantities.^{[35]}
In spectrometry and optics, the blocking unit used to measure optical density is equivalent to −1 B.
In connection with video and digital image sensors, decibels generally represent ratios of video voltages or digitized light intensities, using 20 log of the ratio, even when the represented intensity (optical power) is directly proportional to the voltage generated by the sensor, not to its square, as in a CCD imager where response voltage is linear in intensity.^{[36]} Thus, a camera signaltonoise ratio or dynamic range quoted as 40 dB represents a ratio of 100:1 between signal intensity and noise intensity, not 10,000:1.^{[37]} Sometimes the 20 log ratio definition is applied to electron counts or photon counts directly, which are proportional to sensor signal amplitude without the need to consider whether the voltage response to intensity is linear.^{[38]}
However, as mentioned above, the 10 log intensity convention prevails more generally in physical optics, including fiber optics, so the terminology can become murky between the conventions of digital photographic technology and physics. Most commonly, quantities called "dynamic range" or "signaltonoise" (of the camera) would be specified in 20 log dB, but in related contexts (e.g. attenuation, gain, intensifier SNR, or rejection ratio) the term should be interpreted cautiously, as confusion of the two units can result in very large misunderstandings of the value.
Photographers typically use an alternative base2 log unit, the stop, to describe light intensity ratios or dynamic range.
Suffixes are commonly attached to the basic dB unit in order to indicate the reference value by which the ratio is calculated. For example, dBm indicates power measurement relative to 1 milliwatt.
In cases where the unit value of the reference is stated, the decibel value is known as "absolute". If the unit value of the reference is not explicitly stated, as in the dB gain of an amplifier, then the decibel value is considered relative.
The SI does not permit attaching qualifiers to units, whether as suffix or prefix, other than standard SI prefixes. Therefore, even though the decibel is accepted for use alongside SI units, the practice of attaching a suffix to the basic dB unit, forming compound units such as dBm, dBu, dBA, etc., is not.^{[13]} The proper way, according to the IEC 600273,^{[12]} is either as L_{x} (re x_{ref}) or as L_{x/xref}, where x is the quantity symbol and x_{ref} is the value of the reference quantity, e.g., L_{E} (re 1 μV/m) = L_{E/(1 μV/m)} for the electric field strength E relative to 1 μV/m reference value.
Outside of documents adhering to SI units, the practice is very common as illustrated by the following examples. There is no general rule, with various disciplinespecific practices. Sometimes the suffix is a unit symbol ("W","K","m"), sometimes it is a transliteration of a unit symbol ("uV" instead of μV for microvolt), sometimes it is an acronym for the unit's name ("sm" for square meter, "m" for milliwatt), other times it is a mnemonic for the type of quantity being calculated ("i" for antenna gain with respect to an isotropic antenna, "λ" for anything normalized by the EM wavelength), or otherwise a general attribute or identifier about the nature of the quantity ("A" for Aweighted sound pressure level). The suffix is often connected with a dash (dBHz), with a space (dB HL), with no intervening character (dBm), or enclosed in parentheses (dB(sm)).
Since the decibel is defined with respect to power, not amplitude, conversions of voltage ratios to decibels must square the amplitude, or use the factor of 20 instead of 10, as discussed above.
Probably the most common usage of "decibels" in reference to sound level is dB SPL, sound pressure level referenced to the nominal threshold of human hearing:^{[44]} The measures of pressure (a field quantity) use the factor of 20, and the measures of power (e.g. dB SIL and dB SWL) use the factor of 10.
See also dBV and dBu above.
Attenuation constants, in fields such as optical fiber communication and radio propagation path loss, are often expressed as a fraction or ratio to distance of transmission. dB/m represents decibel per meter, dB/mi represents decibel per mile, for example. These quantities are to be manipulated obeying the rules of dimensional analysis, e.g., a 100meter run with a 3.5 dB/km fiber yields a loss of 0.35 dB = 3.5 dB/km × 0.1 km.
[…] the decibel represents a reduction in power of 1.258 times […]
[…] a pressure ratio of 1.122 equals + 1.0 dB […]
dBZ stands for decibel relative to Z. It is a logarithmic dimensionless technical unit used in radar, mostly in weather radar, to compare the equivalent reflectivity factor (Z) of a radar signal reflected off a remote object (in mm6 per m3) to the return of a droplet of rain with a diameter of 1 mm (1 mm6 per m3). It is proportional to the number of drops per unit volume and the sixth power of drops' diameter and is thus used to estimate the rain or snow intensity. With other variables analyzed from the radar returns it helps to determine the type of precipitation. Both the radar reflectivity factor and its logarithmic version are commonly referred to as reflectivity when the context is clear.
DBmdBm (sometimes dBmW or decibelmilliwatts) is unit of level used to indicate that a power ratio is expressed in decibels (dB) with reference to one milliwatt (mW). It is used in radio, microwave and fiberoptical communication networks as a convenient measure of absolute power because of its capability to express both very large and very small values in a short form compared to dBW, which is referenced to one watt (1,000 mW).
Since it is referenced to the watt, it is an absolute unit, used when measuring absolute power. By comparison, the decibel (dB) is a dimensionless unit, used for quantifying the ratio between two values, such as signaltonoise ratio.
The dBm is also dimensionless but since it compares to a fixed reference value the dBm rating is an absolute one.
In audio and telephony, dBm is typically referenced relative to a 600ohm impedance, while in radiofrequency work dBm is typically referenced relative to a 50ohm impedance.
Dbx (company)dbx, Inc. is an American producer of professional audio recording equipment owned by Harman International Industries, a subsidiary of South Korean firm Samsung Electronics. It was founded by David E. Blackmer in 1971.The original company goal was: "To get closer to the realism of a live performance." Its early products were based on the concept of using decibel expansion which gave the company its name. dbx is best known for the dbx noise reduction system. The dbx noise reduction system used compression while recording an audio track and symmetric expansion when playing it back. They also manufactured the Model 700, a unique but shortlived studio recording system, briefly popular in some circles as a mastering format. Another early product was the eXpanded range DeciBel meter, a little solidstate meter that measured audio voltages both weaker and stronger than other bigger contemporary voltmeters, built into an aluminum extrusion that was about the size of the meter itself, which was an earlier source of the company initials.
Decibel (magazine)Decibel is a monthly heavy metal magazine published by the Philadelphiabased Red Flag Media since October 2004. Its sections include Upfront, Features, Reviews, Guest Columns and the Decibel Hall of Fame. The magazine's tagline is currently "Extremely Extreme" (previously "The New Noise"); the editorinchief is Albert Mudrian.
Decibel FestivalDecibel Festival is an annual music and digital arts festival started in 2004 in Seattle by Sean Horton, who is originally from Detroit. Decibel is dedicated to live electronic music performance, visual art and new media.
Decibel wattThe decibel watt or dBW is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt. It is used because of its capability to express both very large and very small values of power in a short range of number; e.g., 1 milliwatt = −30 dBW, 1 watt = 0 dBW, 10 watts = 10 dBW, 100 watts = 20 dBW, and 1,000,000 W = 60 dBW.
and also
Compare dBW to dBm, which is referenced to one milliwatt (0.001 W).
A given dBW value expressed in dBm is always 30 more because 1 watt is 1,000 milliwatts, and a ratio of 1,000 (in power) is 30 dB; e.g., 10 dBm (10 mW) is equal to −20 dBW (0.01 W).
Although the decibel (dB) is permitted for use alongside SI units, the dBW is not.
F.O.D. (Fuck of Death)"F.O.D. (Fuck of Death)" is a song by Canadian extreme metal band Slaughter. Written by bandmembers Dave Hewson, Terry Sadler and Ron Sumners and produced by Brian Tailor, the song was included in the band's 1987 debut album, Strappado, released in 1987 via Diabolic Force and Fringe Records.
The song bears the same title as the band's 2004 live album, Fuck of Death.
Forest of EquilibriumForest of Equilibrium is the debut album of the British doom metal band Cathedral, released in 1991 on Earache Records. It is considered a classic of its genre, doom metal. Forest of Equilibrium was notably inducted into Decibel Magazine's Hall of Fame in February 2006 being the 12th inductee for the Decibel Hall of Fame.In 2009, Earache Records reissued the album along with four "bonus" songs that comprise the long outofprint 1992 Soul Sacrifice EP. This deluxe digipak reissue also includes a poster of Dave Patchett's cover art and a new 40minute documentary entitled "Return to the Forest" on DVD.
Icon (Paradise Lost album)Icon is the fourth studio album by British heavy metal band Paradise Lost in 1993. It marked a departure from the deathdoom sound of their early work, and was the last album to feature Matthew Archer on drums.
In February 2018, Icon was inducted into the Decibel Magazine Hall of Fame, becoming the second Paradise Lost album to be featured in the Decibel Hall of Fame (alongside Gothic), with the magazine naming it influential to the development of the gothic metal subgenre.
Institute of EvilThe Institute of Evil is a fictional organization appearing in American comic books published by Marvel Comics.
Integrity (band)Integrity is a hardcore punk band originally from America founded in 1988 by vocalist, lyricist and visual artist, Dwid Hellion. Integrity relocated to Belgium since 2004.
The band has a rich history in underground hardcore and metalrelated music, appearing on nearly fifty recordings since 1988 (including 12 fulllength albums and several EP's, reissues and compilation appearances); Integrity have had a strong live presence since their formation, having played hundreds of shows including numerous global festival appearances.
Their sound is known for a mix of hardcore punk and heavy metal with dark religious undertones, prominent use of lead guitars and solos, harsh vocals, occasional sampling and unusual influences such as industrial, noise and experimental music.
Lyrical themes include religion, the supernatural, art, philosophy, horror, as well as mental illness and the occult.
Logarithmic scaleA logarithmic scale is a nonlinear scale used for a large range of positive multiples of some quantity. Common uses include earthquake strength, sound loudness, light intensity, and pH of solutions.
It is based on orders of magnitude, rather than a standard linear scale, so the value represented by each equidistant mark on the scale is the value at the previous mark multiplied by a constant.
Logarithmic scales are also used in slide rules for multiplying or dividing numbers by adding or subtracting lengths on the scales.
Melodifestivalen 1978Melodifestivalen 1978 was the selection for the 18th song to represent Sweden at the Eurovision Song Contest. It was the 17th time that this system of picking a song had been used. 58 songs were submitted to SVT for the competition. The final was broadcast on TV1 but was not broadcast on radio. The songs were not performed live, instead the performances were recorded the afternoon before, and intermingled with live pieces from the venue. There was a tie in the voting, and each regional jury was asked to award one point to their favourite song of "Det blir alltid värre framåt natten" and "Miss Decibel". The former won by eight votes to three.
Miss DecibelMiss Decibel is a 1978 studio album from Swedish "dansband" Wizex. The album contained the song "Miss Decibel", which was listed on Svensktoppen, along with the song "Om en stund". The album reached #2 on the Swedish popular music charts.
Miss Decibel (song)Miss Decibel, written by Lasse Holm and Gert Lengstrand, is a song in Swedish, which finished 2nd at the Swedish Melodifestivalen 1978. It was performed by the Swedish "dansband" Wizex, back then including Kikki Danielsson as lead vocal singer, together with Lasse Holm. The song, which lyrical describes about a little singingscreaming girl and her parents who see her screaming abilities as an opportunity to become a singing star in the future, ends with a refrain in English including the words "Decibel, you gonna be a star".
Björn Skifs won that year's Melodifestivalen with the song "Det blir alltid värre framåt natten".
The single peaked at #10 at the Swedish singles chart. The song was also at Svensktoppen for eleven weeks during the period April 16June 25, 1978, peaking at #2.
The song was covered by Eva Rydberg later in 1978, on her album "Sång á la Rydberg". In 1979, musician Nils Dacke recorded the song for his album "Nils Dacke spelar partyorgel".
In 2008 the song was performed at Dansbandskampen by Martinez.At Så mycket bättre 2017, the song was recorded by Uno Svenningsson as "Prins Decibel".
My Wicked TwinMy Wicked Twin are a Canadian hard rock band from Kitchener, Ontario that formed in 2008. They have their genesis in an earlier band called Brent Doerner's Decibel, which suffered from less than satisfactory sales. Revamped as My Wicked Twin, they now consist of Brent Doerner of Helix, his twin brother Brian Doerner of Saga (also exHelix), Uzi (Mike Uzelac) (also exHelix), and Shane Schedler (exMartyrs of Melody). Brent and Brian Doerner had been playing music together since the age of 8.
NeperThe neper (symbol: Np) is a logarithmic unit for ratios of measurements of physical field and power quantities, such as gain and loss of electronic signals. The unit's name is derived from the name of John Napier, the inventor of logarithms. As is the case for the decibel and bel, the neper is a unit defined in the international standard ISO 80000. It is not part of the International System of Units (SI), but is accepted for use alongside the SI.
WizexWizex is a Swedish dansband, formed in Osby, Sweden in 1973, with Kikki Danielsson as singer. The band has since had several front singers.
Wizex finished 2nd in the Swedish Melodifestivalen 1978.
Big hits with Wizex were songs as Tusen och en natt, Djupa vatten, Miss Decibel, Älska mig, Om himlen och Österlen, Flickan, jägarn och priset, Jag måste nå min ängel, Som en symfoni and När vi rör varann.
The record Take Me To Your Heaven sold 235 000 copies. Wizex also had many Svensktoppen hits.
In 1979, Wizex won the Rockbjörnen award by Aftonbladet as "dansband of the year". This was the only time this category was included.
Decibel suffixes (dB)  

Base units  

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