dB conversion dBu and dBV to volts V - 0 dB dBm audio level calculator - sengpielaudio Checker
 
Deutsche Version UK-flag s/w - sengpielaudio D-flag - sengpielaudio
 
Conversion
  Voltage V to voltage level Lu and LV
• 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

 Lu    dBu   |     LV    dBV   |   V  volts (RMS) 
      |         |      
↓   |   ↓   |   ↓
      |         |      
LV dBV   |   Lu dBu   |     Lu     dBu
V volts (RMS)    |   V volts (RMS)    |   LV  dBV
      |         |      
  volts (p-p)   |     volts (p-p)   |    

Fill out a gray box above and click the respective 'calculate' bar under it.
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
calcualtions can made easier with RMS = amplitude / √2 

Level   Formula volt to level        Voltage   Formula level to volt

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

Rainbow - sengpielaudio

dBFS - Digital recording level

♦ 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.

All 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 always unused forbidden zone.

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 R68-1992 - The European Broadcasting Union recommends: digital level
-9 dBFs (maximum). Reference level -18 dBFs. 0 dBFs equal to +15 dBu.

Rainbow - sengpielaudio

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.

Voltage V (audio):
volts		  ↔  Voltage level LV:
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 LU:
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 LP:
dB
Formi   Formula
Reference electric power P0 = 1 W ≡ 0 dB

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

Electric power (telephone) P:
watts		  ↔  Electric Power level LP
dBm
Start   Start
Reference power P0 = 1 milliwatt (mW) = 0.001 W ≡ 0 dBm

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 (VRMS) Peak voltage (Vp) Peak-to-peak voltage (Vp-p)
0 volts 117 volts = VRMS 165 volts = √2×VRMS 330 volts = 2×√2×VRMS
0 volts 230 volts = VRMS 325 volts = √2×VRMS 650 volts = 2×√2×VRMS
Enter one known voltage:
VRMS = volts
Vpeak = volts
Vp-p   = volts
Do not reenter an answer!
 
Voltage RMS Peak - sengpielaudio
  VRMS Vp Vp-p
RMS value     VRMS = − 0.7071 × Vp 0.3535 × Vp-p

Peak value     Vp      =

1.414 × VRMS − 0.5000 × Vp-p
Peak to peak Vp-p  = 2.828 × VRMS 2.000 × Vp −

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 technique, no impedance reference!
Voltage V0 = 1 V ≡ 0 dBV Audio technique, USA
Voltage V0 = 1×10−6 V   HF receiver and amplifier technique
Voltage V0 = 0.224 V   HF technique - 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 = 7.78 dBu - Reference 0.7746 V
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    

Note - Comparing dBSPL and dBA: There is no conversion formula for
measured dBA values to sound pressure level dBSPL or vice versa.
That is only possible measuring one single frequency.

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