What Happens When The Electric Meter One Leg Register 248 Volt But Other Leg Register 0.00?

Fill up out a gray box higher up and click the respective 'calculate' bar under it. p-p = peak to peak.
The reference voltage for 0 dBu is 0.775 volt (0.77459667 V) and for 0 dBV it is exactly ane.0 volt.
Curl down to find the formulas for voltage and ability and the calculation of the absolute level.

The origin of the index of dBu comes from "u = unloaded" and dBV comes from "V = 1 volt". Some say:
The "u" in dBu implies that the load impedance is unspecified, unterminated, and is likely to be high.

What is dBu? A logarithmic voltage ratio with a reference voltage of V ₀ = 0.7746 volt ≡ 0 dBu
What is dBV? A logarithmic voltage ratio with a reference voltage of 5 ₀ = 1.0000 volt ≡ 0 dBV
The dwelling house recording level (consumer sound) of −x dBV ways 0.3162 volts, that is −7.78 dBu.
The studio recording level (pro audio) of +four dBu ways a voltage of 1.228 volts.
The maximum undistorted level of audio amplifiers is +eighteen dBu. In Usa it is +24 dBu.
Domestic gear with a −10 dBV level is usually unbalanced. Studio gear with a +4 dBu level is always balanced. 0 VU = +4 dBu.

Scale: Level in dBu and dBV in comparing to the voltage in V

Voltage in V und level in dBu and dBV

	Level dBu	Voltage volt	Level dBV
Studio level international	+4●	1.228	+1.78
Standard level 1 Volt	+2.22	1	0 ref.
Standard level 0.775 Volt	0 ref.	0.775	−2.22
Domestic level	−seven.78	0.316	−ten●

The level departure between +4 dBu studio level
and −ten dBV consumer level is Δ L = 11.78 dB (12 dB).

The level difference between dBu level and dBV level is Δ 50 = 2.two dB.
0 dBV equals 2.ii dBu or 0 dBu equals −2.ii dBV.

The conversion from level L (dBu) to voltage (volt) is 5 = 0.775 × ten ^(Fifty ^/20).
The conversion from voltage 5 (volt) to level (dBu) is 50 = twenty × log ( V /0.775).

All field quantities, similar voltage or sound pressure level are
ever true RMS values, if non otherwise stated.

In mathematics, the root mean square (abbreviated RMS
or rms), also known as the quadratic mean, is a statistical
measure out of the magnitude of a varying quantity.

For sinusodial voltages or currents with ohm'due south loads
calculations can made easier with RMS = aamplitude / √2

Level

Voltage

Note - Comparing dBSPL and dBA: In that location is no conversion formula for
measured dBA values to sound pressure level dBSPL or vice versa.
Also you cannot convert "dBA to volts" and vice versa.
Conversion is just possible for measuring one single frequency.

Pro audio equipment often lists an A-weighted racket spec – non
because it correlates well with our hearing – simply because information technology can
"hide" nasty hum components that make for bad racket specs.

Words to bright minds: Always wonder what a manufacturer
is hiding when they utilise A-weighting. *)

*) http://world wide web.google.com/search?q=Always+wonder+what+a+manufacturer+Rane&filter=0

Explanation: What is "dBFS"? (Digital Sound)

dBFS - Digital recording level

Analog levels and digital levels are different realms.

♦ An oftentimes posted question: "Delight, tin yous help me catechumen from dBFS to dBu".
Never express analog signal levels in terms of dBFS.
Follow this and you will not misfile anyone.

There is no decibel to dBFS converter
Detect - Comparing dBu and dBFS: There is really no fixed
globe standard like due east.g. −20 dBFS = +4 dBu = 0dBVU.
The digital peak scale is not equivalent to the analog RMS scale.

You can never match dBFS and dBu.

dBu is volts - you measure it with a volt meter.
Analog audio: positive and negative voltage.

dBFS is in contrast a binary number.
Digital audio: zeroes and ones.

There is no such matter equally peak volts dBu *)

Information technology is incorrect to state peak voltage levels in dBu.

*) http://www.rane.com/note169.html
*) http://www.rane.com/pdf/ranenotes/No_Such_Thing_as_Peak_Volts_dBu.pdf

dBFS must take a minus sign at the beginning. There is not something like +6 dBFS.

There is no such standardized reference. ten dBFS is a digital voltage level
(peak) and y dBVU or dBu is an analog voltage level (RMS).

Digital and analogue are two totally different realms.

That's why there is no relation between dBFS and dBVU or dBu, whatsoever.
Analog meter (ppm): attack time ten to 300 ms − reading rms values.
Digital meter: set on time < one ms − reading elevation values. That is really some
difference.

Advice: Watch simply your digital meters and go up to 0 dBFS, but never become
over this mark. We use "headroom" in the analog domain. That is OK, but
we don't need digital "headroom" as an always "unused" forbidden
zone.
You are gratuitous to choose your private headroom, if you similar that, but there is no
standard that y'all have to do that.
The demand for a high modulation level, stand in the contrary to the merits,
to avert overloading.

Never take the following funny guessing game for granted. Use it only every bit a rough guide:
European & UK scale for Post & Film is −18 dBFS = 0 VU = +iv dBu

BBC spec: −18 dBFS = PPM "4" = 0 dBu
American Post: −20 dBFS = 0 VU = +4 dBu
Orchestral −18 dBFS = 0 VU = +four dBu
Rock and / or Radio −16, or −fourteen, or −12 dBFS = 0 VU = +4 dBu
Digi 002 is only capable of −xiv dBFS.
German language ARD & studio PPM +6 dBu = −10 (−9) dBFS. +16 (+xv) dBu = 0 dBFS. No VU.

• EBU R68-2000 - The European Dissemination Union recommends: digital level
−9 dBFs (maximum). You accept to keep the upper 9 dBs empty without any use.
The reference level is −18 dBFs. 0 dBFs is equal to +15 dBu.
Detect: 0 dBFS is the permitted maximum digital level.

The EBU broadcasters take a problem, because they want to apply the onetime wearisome meters with the
dBu scale (attack 10 ms, quasi-elevation) of the analog times for digital recordings.
The rest of the world looks e'er at the fast digital meters (attack < 1 ms, peak) with the dBFS
scale. Forget looking at the dBu calibration of the meters.
Information technology seems to come a change from QPPM-modulation to loudness (ITU/EBU) and true-acme.
Wait at: EBU R 128 .

Note: The guidelines of the EBU to fix the maximum gain
to −ix dB dBFS should not apply if non working for the
European Dissemination Union. Whose maximum levels
of digital CD masters are −9dBFS, should not be
surprised if the CDs are not loud enough.
9 dB upwardly to the top are left free with really no use.

LUFS = Loudness Units relative to Full Calibration

The formulas for voltage and power
and the calculation of the accented level

To utilize the calculator, simply enter a value.
The calculator works in both directions of the ↔ sign.

dBm indicates that the reference ability is P ₀ = ane milliwatt = 0.001 watt ≡ 0 dB

Conversion of voltage or ability ratios to decibels dB - table and chart

Table of Sound Force per unit area Levels and Corresponding Audio Pressure and Sound Intensity RMS voltage , elevation voltage and peak-to-elevation voltage

The parameters of the mains or "power" sine wave form are summarized at the table below:

Boilerplate voltage	RMS voltage ( V _RMS)	Peak voltage ( V _p) = ( Û )	Summit-to-peak voltage ( Five _pp)
0 volts	117 volts = 5 _RMS = ~ V	165 volts = √2× V _RMS = 0,5 × V _pp	330 volts = two×√ii× V _RMS = 2 × V _p
0 volts	230 volts = Five _RMS = ~ Five	325 volts = √2× V _RMS = 0,5 × V _pp	650 volts = two×√ii× 5 _RMS = 2 × V _p

The value 5 _RMS of an alternating voltage V (t) = V ₀ × f(t)is defined and then that the
effective DC ability corresponds V _RMS ² / R = 5 _RMS × I _RMS to an ohmic resistance
of the middle resistive power of this Air-conditioning voltage to the same resistance.

The crest gene means the ratio of the elevation voltage to the RMS voltage.
If yous need to calculate an attenuator (attenuation adding) you calculate a voltage divider.

Voltage conversions

Voltage	Five _RMS = ~ Five	5 _p	Five _pp
Average voltage RMS V _RMS =	−	0.7071 × Five _p	0.3535 × V _pp
Height voltage Five _p =	i.414 × V _RMS	−	0.5000 × Five _pp
Peak-to-peak voltage V _pp =	2.828 × V _RMS	2.000 × 5 _p	−

Dissimilar voltage levels

Level	Level L in dB	Voltage RMS	Voltage peak-to-pinnacle
European studio level - ARD circulate level	+6 dBu	ane.55 V	iv.38 V
International studio level - USA	+4 dBu	one.228 5	3.47 V
Domestic recording (Consumer units)	−10 dBV	0.3162 V ≡ −7.78 dBu	0.894 V
Acoustic level (auditory threshold)	0 dB	2×x⁻⁵ Pa ≡ 0 dBSPL	5.66×x^−v Pa
Reference studio level re 0.775 volt	0 dBu	0.7746 V	2.19 5
Reference studio level re 1 volt	0 dBV	1.0000 V	2.828 V

International reference values

Physical unit of measurement	Level unit	Reference value	Note
Voltage	Five ₀ = 0.775 V	≡ 0 dBu	Audio engineering, no impedance reference!
Voltage	V ₀ = one Five	≡ 0 dBV	Sound engineering science, USA
Voltage	V ₀ = 1×x^{−half dozen} 5		HF receiver and amplifier engineering
Voltage	V ₀ = 0.224 V		HF engineering science - Reference 1 mW at Z = 50 Ω
Voltage	V = 1.228 V		Studio level +4 dBu, USA - Reference 0.7746 V
Voltage	V = ane.55 5		Studio level +half-dozen dBu, ARD - Reference 0.7746 5
Voltage	V = 0.3162 V		Dwelling house recording level −10 dBV - Reference ane.0 V ≡ −7.78 dBu
Sound pressure	p ₀ = 2×10^−v Pa	≡ 0 dB	Sound Pressure Level SPL, auditory threshold (Sound field size)
Audio particle velocity	5 ₀ = v×10⁻⁸ thou/s	≡ 0 dB
Sound intensity	I ₀ = i×10⁻¹² W/mⁱⁱ	≡ 0 dB	Threshold of pain at ane West/m^two (Audio free energy size)
Power	P ₀ = 1 West	≡ 0 dBW	The reference impedance must always be told
Power	P ₀ = ane mW	≡ 0 dBm	Z = 600 Ω (telephones) or Z = 50 Ω (antennas)
Electrical field strength	East ₀ = i×x^{−half-dozen} V/m

Decibels (dB) Estimator

Decibels are divers as ten times the log of a power ratio. Decibels catechumen
multiplication and division calculations into uncomplicated add-on and subtraction operations.

This calculator converts betwixt decibels, voltage proceeds (or electric current), and power proceeds.
But fill in one field and the calculator volition convert the other two fields.

Equations: Level in dB: 50 = 20 × log ( 5 ₁/ V ₂) = ten × log ( P ₁/ P ₂)

The dBm is a logarithmic measure of power compared to 1 mW,
that means it is power dependent.
It tin can be converted to a voltage, if the load impedance is known.
Typically the impedance (load) is 600 ohms.

Equation: Level in dBm: L _P = 10 × log ( P / 0.001)

Elementary dominion of thumb: When working with ability: 3 dB is twice, 10 dB is ten times.
When working with voltage or current: 6 dB is twice, 20 dB is 10 times.

Why is the bandwidth and the cutoff frequency establish at the level of "−3 dB"?
Why we always take 3 dB down gain of a filter?
Full width at half maximum (FWHM).
Reply: That is the indicate where the free energy (ability) is fallen to the value ½ or 0.5 = 50 percent of the initial power as free energy
quantity, that is equivalent to (−)3 dB = 10×log(0.5). A (−)iii dB ability driblet is a decrease of 50 % to the value of l%.
In that location the voltage is fallen to the value of √(½) or 0.7071 = seventy.71 percent of the initial voltage every bit field quantity equivalent to
(−)3 dB = 20×log(0.7071). A (−)iii dB voltage drop is a subtract of 29.29 % to the value of 70.71 %.

(−)iii dB implies ½ the electric power and since the ability is proportional to the
square of voltage, the value volition be 0.7071 or 70.71 % of the passband voltage.
√½ = 1/√2 = √0,v = 0,7071. P ~ 5 ², that is 0,v ~ 0,7071^two.

Sound engineers and sound designers ("ear people") generally utilize the usual (audio) field quantity. That'swhy they say:
The cutoff frequency of a device (microphone, amplifier, loudspeaker) is the frequency at which the output voltage level
is decreased to a value of (−)3 dB beneath the input voltage level (0 dB).
● (−)3 dB corresponds to a factor of √½ = 1/√two = 0.7071, which is 70.71% of the input voltage.

Acousticians and audio protectors ("noise fighters") seem to like more the (sound) energy quantity. They tell us:
The cutoff frequency of a device (microphone, amplifier, loudspeaker) is the frequency at which the output power level is
decreased to a value of (−)3 dB below the input power level (0 dB).
● (−)3 dB corresponds to a factor of ½ = 0.5, which is fifty% of the input power (half the value)..

Notation: Power proceeds (power amplification) is not common in audio engineering.
Even power amplifiers for loudspeakers don't amplify the power.
They amplify the sound voltage that moves the voice curl.

Note: A sound field quantity (sound pressure p , electric voltage V ) is not a sound free energy
quantity (sound intensity I , audio ability P _ak). I ~ p ⁱⁱ or P ~ Five ². Sometimes you can hear
the argument: The cutoff frequency is there where the level L is decreased by (−)3 dB.
Whatsoever the user wants to tell us and then accurately: Level is level or dB is dB.