dB chart voltage power sound pressure sound intensity dB decibel level ratio table absolute relative voltage level database - sengpielaudio
 
Deutsche Version UK-flag s/w - sengpielaudio D-flag - sengpielaudio
 
Relative level − decibel  chart
and dB conversion calculator
 
The dB calculator - a valuable tool
 
Conversion of voltage or power  ratios to decibels dB
Table and chart − volts, watts, and pascals, W/m2

The sound pressure deviation is the instantaneous acoustic pressure as RMS value.

Voltage or
sound
pressure
ratio		 Power
or
intensity
ratio		  ← − dB + → Voltage or
sound
pressure
ratio		 Power
or
intensity
ratio
1.000 1.000 0 1.000 1.000
0.989 0.977 0.1 1.012 1.023
0.977 0.955 0.2 1.023 1.047
0.966 0.933 0.3 1.035 1.072
0.955 0.912 0.4 1.047 1.096
0.944 0.891 0.5 1.059 1.122
0.933 0.871 0.6 1.072 1.148
0.923 0.851 0.7 1.084 1.175
0.912 0.832 0.8 1.096 1.202
0.902 0.813 0.9 1.109 1.230
0.891 0.794 1.0 1.122 1.259
0.841 0.708 1.5 1.189 1.413
0.794 0.631 2.0 1.259 1.585
0.750 0.562 2.5 1.334 1.778
0.707 0.501 3.0 1.413 1.995
0.668 0.447 3.5 1.496 2.239
0.631 0.398 4.0 1.585 2.512
0.596 0.355 4.5 1.679 2.818
0.562 0.316 5.0 1.778 3.162
0.531 0.282 5.5 1.884 3.548
0.501 0.250 6.0 1.995 4.000
0.473 0.224 6.5 2.113 4.467
0.447 0.200 7.0 2.239 5.012
0.422 0.178 7.5 2.371 5.623
0.398 0.159 8.0 2.512 6.310
0.376 0.141 8.5 2.661 7.079
0.355 0.126 9.0 2.818 7.943
0.335 0.112 9.5 2.985 8.913
0.316 0.100 10 3.162 10.00
0.282 0.0794 11 3.55 12.6
0.251 0.0631 12 3.98 15.8
0.224 0.0501 13 4.47 20.0
0.199 0.0398 14 5.01 25.1
0.178 0.0316 15 5.62 31.6
0.159 0.0251 16 6.31 39.8
0.141 0.0200 17 7.08 50.1
0.126 0.0159 18 7.94 63.1
0.112 0.0126 19 8.91 79.4
0.100 0.0100 20 10.0 100.0
3.16×10−2 10−3 30 3.16×10 103
10−2 = 0.01 10−4 40 102 = 100 104
3.16×10−3 10−5 50 3.16×102 105
10−3 = 0.001 10−6 60 103 = 1000 106
3.16×10−4 10−7 70 3.16×103 107
10−4 10−8 80 104 108
3.16×10−5 10−9 90 3.16×104 109
10−5 10−10 100 105 1010
3.16×10−6 10−11 110 3.16×105 1011
10−6 10−12 120 106 1012

Enter a value in the left or right box.
The calculator works in both directions of the ↔ sign.

Voltage ratio:
V ratio = V2/V1		  ↔  Voltage level LV:
dB
Formula Voltage Ratio   Formula Voltage Level
Voltage ratio 1 ≡ 0 dB at reference Vin = 1 volt
Power ratio:
P ratio = P2/P1		  ↔  Power level LP:
dB
Formula Power Ratio   Formula Power Level
Power ratio 1 ≡ 0 dB at reference Pin = 1 watt

For dBm it was decided a reference power P0 or Pin = 1 milliwatt (mW) = 0.001 W ≡ 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
Voltage Ratio and Voltage Level - sengpielaudio Power Ratio and Power Level - sengpielaudio
Level of field quantities
Formula Voltage		 Level of energy quantities
Formula power level

We are mainly concerned with conditions of sound pressure,
sound velocity, and audio voltage that are sound field quantities.
Voltage level is: LV = 20 × log (V1 / V0)       Reference voltage V0 = 1 Volt.
Voltage is: V1 = V0 × 10(LV / 20)

Sound Field Quantities    AnimatedLaughingSmiley
Sound pressure, sound or particle velocity,
particle displacement or particle ampliude,
(voltage, current, electric resistance).
Inverse Distance Law 1/r		 Sound Energy Quantities
Sound intensity, sound energy density,
sound energy, acoustic  power.
(electrical power).
Inverse Square Law 1/r²

Decibel scale for linear field quantities, like volts and sound pressures
dB-Ratio - sengpielaudio.com
The logarithmic scale (ratio)

Absolute level − dB chart

referred to 0.7746 volt in dBu and to 1 volt in dBV

Conversion of decibel to voltage re 0.7746 volt and re 1 volt

Voltage re
0.7746 volt		 Voltage re
1 volt		  ← – dB + → Voltage re
0.7746 volt		 Voltage re
1 volt
0.775 1.000 0 0.775 1.000
0.766 0.989 0.1 0.784 1.012
0.757 0.977 0.2 0.793 1.023
0.748 0.966 0.3 0.802 1.035
0.740 0.955 0.4 0.811 1.047
0.731 0.944 0.5 0.820 1.059
0.723 0.933 0.6 0.830 1.072
0.715 0.923 0.7 0.840 1.084
0.706 0.912 0.8 0.849 1.096
0.698 0.902 0.9 0.859 1.109
0.690 0.891 1.0 0.869 1.122
0.652 0.841 1.5 0.921 1.189
0.615 0.794 2.0 0.975 1.259
0.581 0.750 2.5 1.033 1.334
0.548 0.707 3.0 1.095 1.414
0.518 0.668 3.5 1.159 1.496
0.489 0.631 4.0 1.228 1.585
0.461 0.596 4.5 1.300 1.679
0.436 0.562 5.0 1.377 1.778
0.411 0.531 5.5 1.459 1.884
0.388 0.501 6.0 1.549 1.995
0.367 0.473 6.5 1.637 2.113
0.346 0.447 7.0 1.734 2.239
0.327 0.422 7.5 1.837 2.371
0.308 0.398 8.0 1.946 2.512
0.291 0.376 8.5 2.061 2.661
0.275 0.355 9.0 2.183 2.818
0.259 0.335 9.5 2.312 2.985
0.245 0.316 10 2.449 3.162
0.218 0.282 11 2.748 3.548
0.195 0.250 12 3.084 3.981
0.173 0.224 13 3.460 4.467
0.155 0.199 14 3.882 5.012
0.138 0.178 15 4.356 5.623
0.123 0.159 16 4.887 6.310
0.109 0.141 17 5.484 7.079
0.097 0.129 18 6.153 7.943
0.086 0.112 19 6.904 8.912
0.077 0.100 20 7.746 10.000
2.450×10−2 3.162×10−2 30 24.50 31.62
7.746×10−3 10−2 40 77.46 102
2.450×10−3 3.162×10−3 50 2.450×102 3.162×102
7.746×10−4 10−3 60 7.746×102 103
2.450×10−4 3.162×10−4 70 2.450×103 3.162×103
7.746×10−5 10−4 80 7.746×103 104
2.450×10−5 3.162×10−5 90 2.450×104 3.162×104
7.746×10−6 10−5 100 7.746×104 105
2.450×10−6 3.162×10−6 110 2.450×105 3.162×105
7.746×10−7 10−6 120 7.746×105 106

Audio voltage and level

Enter a value in the left or right box.
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 LV:
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
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.

There is no "dBA" curve given as threshold of human hearing. 
Readings of a pure 1 kHz tone should be identical, whether weighted or not.

 
 Pro audio equipment often lists an A-weighted noise spec
 – not because it correlates well with our hearing – but because it
 can "hide" nasty hum components that make for bad noise specs.
 
 Words to bright minds: 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

Sound measuring (Noise measuring) with weighting filter A and C

 
If the output voltage level is 0 dB, that is 100%, the level of −3 dB
is equivalent to 70.7% and the level of −6 dB is equivalent to 50%
of the initial output voltage.
This applies to all field quantities; e.g. sound pressure.

If the output power level is 0 dB, that is 100%, the level of −3 dB
is equivalent to 50% and −6 dB is equivalent to 25% of the initial
output power.
This applies to all energy quantities; e.g. sound intensity.

Try to understand this.
 

Different equations in books −
RMS or peak value?

The sound intensity I in W/m2 in a plane progressive wave is given as:

                            or also as

But only one equation can be correct.

Sometimes, these equations will show further information:

                            or also as

                           

The tilde will indicate that it is the RMS value and the roof will show that it is the
amplitude value, ie, the peak value. For sinusoidal signals, the peak value means
the amplitude.
With these more accurate data, both equations are correct. You just need to know
exactly whether the peak value or the RMS value is applied.

Sound pressure p in Pa = N/m2 − particle velocity v in m/s − acoustic intensity I in
N/m2 · m/s = W/m²               Energy equivalent: J (joule) = N · m = W · s

In audio engineering we always assume RMS values, if not specially noted different.

Simple rule of thumb: When working with power, 3 dB is twice, 10 dB is 10 times.
When working with voltage or current, 6 dB is twice, 20 dB is 10 times

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