dB dBu dBFS dBV to volts conversion - calculator volt volts to dBu and dBV dB mW - convert dB volt convertor converter calculation online attenuation loss gain ratio reference audio engineering sound recording dBFS dBVU 0 dB audio logarithm level converter peak to peak impedance voltage pro consumer audio digital analog recording level

Conversion
Voltage V to voltage level L_u and L_V
• Decibel (dB) level conversion to volt •
dBu to dBV, or volts (rms), and dBV to dBu, or volts (rms)
volts (rms) to dBu and dBV − p-p = peak to peak

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The reference voltage for 0 dBu is 0.775 volt (0.77459667 V) and for dBV it is exactly 1.0 volt.

The origin of the index of dBu comes from "u = unloaded" and of dBV is 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 V₀ = 0.7746 volt ⇒ 0 dBu
What is dBV? A logarithmic voltage ratio with a reference voltage of V₀ = 1.0000 volt ⇒ 0 dBV
The home recording level (consumer audio) of −10 dBV means 0.3162 volts, that is −7.78 dBu.
The studio recording level (pro audio) of +4 dBu means 1.228 volts.

All field quantities, like the voltage or the sound pressure
are always RMS values, if not otherwise stated.

For sinusodial voltages or currents with ohm's loads
calculations can made easier with RMS = amplitude / √2

Level

Voltage

Note - Comparing dBSPL and dBA: There 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 only possible for measuring one single frequency.

Words to the wise: Always wonder what a manufacturer
is hiding when they use A-weighting. *)

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

If you really need dBm with "m = 1 milliwatt or one thousandth (10⁻³) of a watt", go to:
The dBm calculator and power matching or impedance matching

dBFS - Digital recording level

Analog levels and digital levels are different realms.

♦ An often posted question: "Please, can you help me convert from dBFS to dBu".

Notice - Comparing dBu and dBFS: There is really no fixed
world standard like e.g. −20 dBFS = 0 dBVU = +4 dBu.
The digital peak scale is not equivalent to the analog RMS scale.

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

We got no such standardized reference. x 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.
There is no relation between dBFS and dBVU or dBu, whatsoever.
Analog meter (ppm): attack time 10 to 300 ms − reading rms values.
Digital meter: attack time < 1 ms − reading peak values. That is really
some difference.

Advice: Watch only your digital meters and go up to 0 dBFS, but never
go 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 free to choose your private headroom, if you like that, but there is
no standard that you have to do that.
The demand for a high modulation level, stand in the contrary to the claim,
to avoid overloading.

Never take the following funny guessing game for granted. Use it only as a rough guide:
European & UK calibration for Post & Film is −18 dBFS = 0 VU
BBC spec: −18 dBFS = PPM "4" = 0 dBu
American Post: −20 dBFS = 0 VU = +4 dBu
Orchestral −18 dBFS = 0 VU = +4 dBu
Rock and / or Radio −16, or −14, or −12 dBFS = 0 VU = +4 dBu
Digi 002 is only capable of −14 dBFS.
German ARD & studio PPM +6 dBu = −10 (−9) dBFS. +16 (+15)dBu = 0 dBFS. No VU.
• EBU R68-2000 - The European Broadcasting Union recommends: digital level
−9 dBFs (maximum). You have to keep the upper 9 dBs empty without any use.
The reference level is −18 dBFs. 0 dBFs is equal to +15 dBu.
Notice: 0 dBFS is the permitted maximum digital level.

Note: The guidelines of the EBU to set the maximum gain
to −9 dB dBFS should not apply if not working for the
European Broadcasting Union. Whos maximum level of a
digital CD master is -9dBFS, should not be surprised if the
CDs are not loud enough.

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

Enter a value in the left or right box, then press the TAB bar or make
a mouse click at an empty space at the side, to get the solution.
The calculator works in both directions of the ↔ sign.

dBm indicates that the reference power is P₀ = 1 milliwatt = 0.001 watt ≡ 0 dB

Conversion of voltage or power ratios to decibels dB - table and chart
Table of Sound Pressure Levels and Corresponding Sound Pressure and Sound Intensity

RMS voltage, peak voltage and peak-to-peak voltage

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

Average voltage	RMS voltage (V_RMS)	Peak voltage (V_p)	Peak-to-peak voltage (V_p-p)
0 volts	117 volts = V_RMS	165 volts = √2×V_RMS	330 volts = 2×√2×V_RMS
0 volts	230 volts = V_RMS	325 volts = √2×V_RMS	650 volts = 2×√2×V_RMS

	V_RMS	V_p	V_p-p
RMS value V_RMS =	−	0.7071 × V_p	0.3535 × V_p-p
Peak value V_p =	1.414 × V_RMS	−	0.5000 × V_p-p
Peak to peak V_p-p =	2.828 × V_RMS	2.000 × V_p	−

The crest factor means the ratio of the peak voltage to the RMS voltage.

If you need to calculate an attenuator (attenuation calculation) you calculate a voltage divider.

International levels

Level	Level L in dB	Voltage (RMS)
International studio level - USA	+4 dBu	1.228 V
European studio level - ARD broadcast level	+6 dBu	1.55 V
Domestic recording (Consumer units)	−10 dBV	0.3162 V = −7.78 dBu
Sound pressure level (auditory threshold)	0 dB	2×10⁻⁵ Pa ≡ 0 dBSPL

International reference values

Physical unit	Reference value	Level unit	Note
Voltage	V₀ = 0.775 V	⇒ 0 dBu	Audio engineering, no impedance reference!
Voltage	V₀ = 1 V	⇒ 0 dBV	Audio engineering, USA
Voltage	V₀ = 1×10⁻⁶ V		HF receiver and amplifier technology
Voltage	V₀ = 0.224 V		HF technologye - Reference 1 mW at R = 50 Ω
Voltage	V = 1.228 V		Studio level +4 dBu, USA - Reference 0.7746 V
Voltage	V = 1.55 V		Studio level +6 dBu, ARD - Reference 0.7746 V
Voltage	V = 0.3162 V		Home recording level −10 dBV - Reference1.0 V ≡ −7.78 dBu
Sound pressure	p₀ = 2×10⁻⁵ Pa	⇒ 0 dB	Sound Pressure Level SPL, auditory threshold (Sound field quantity)
Sound particle velocity	v₀ = 5×10⁻⁸ m/s	⇒ 0 dB
Sound intensity	I₀ = 1×10⁻¹² W/m²	⇒ 0 dB	Threshold of pain at 1 W/m² (Sound energy quantity)
Power	P₀ = 1 W	⇒ 0 dBW
Power	P₀ = 1 mW	⇒ 0 dBm	at R = 600 Ω (telephones) or 50 Ω (antennas)
Electric field strength	E₀ = 1×10⁻⁶ V/m

Decibels (dB) Calculator

Decibels are defined as ten times the log of a power ratio. Decibels convert multiplication and division calculations into simple addition and subtraction operations.

This calculator converts between decibels, voltage gain (or current), and power gain. Just fill in one field and the calculator will convert the other two fields.

Equations:

Level in dB = 20 × log (V₁/V₂) = 10 × log (P₁/P₂)

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

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

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Voltage V (audio): volts	↔	Voltage level L_V (audio): dBu
$V = V_0 \cdot 10^\frac{L_V}{20} \ \mbox{volts}$		$L_V = 20\, \log_{10}\left(\frac{V}{V_0}\right) \ \mbox{dBu}$
Reference voltage V₀ = 0.7746 Volt ≡ 0 dBu

Voltage V: volts	↔	Voltage level L_U: dBV
$V = V_0 \cdot 10^\frac{L_V}{20} \ \mbox{volts}$		$L_V = 20\, \log_{10}\left(\frac{V}{V_0}\right) \ \mbox{dBV}$
Reference voltage V₀ = 1 Volt ≡ 0 dBV

Electric power P: watts	↔	Electric power level L_P: dB

Reference electric power P₀ = 1 W ≡ 0 dB

Electric power (telephone) P: watts	↔	Electric Power level L_P dB_m

Reference power P₀ = 1 milliwatt (mW) = 0.001 W ≡ 0 dB_m

Impedance = ohms
dBm	Power(watts)	Voltage DC	V_p of sinusoid