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

The sound pressure variation 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

Field quantity (size)Voltage

To use the calculator, simply enter a value.
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

Energy quantity (size)Power

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 the reference power P1 or 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

Voltage Ratio and Voltage Level        Power Ratio and Power Level
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 field quantities.
Voltage level is: LV = 20 × log10(V1 / V0)
Voltage is: V1 = V0 × 10(LV / 20)
Reference voltage V0 = 1 Volt.

Sound Field Quantities    AnimatedLaughingSmiley
Sound pressure, sound or particle velocity,
particle displacement or displacement amplitude,
(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
The logarithmic scale (ratio)
 
Comparison of sound pressure level SPL and sound intensity level
 
Formula for level
 
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

Voltageáre
0.7746ávolt
Voltageáre
1ávolt
 ← − dB + →  Voltageáre
0.7746ávolt
Voltageáre
1ávolt
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

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

Voltage V (audio)  
volts
 ↔  Voltage level Lu 
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:
 
                            formula or also as formula

 
But only one equation can be correct.
 
Sometimes, these equations will show further information:
 
                            formula or also as formula
 
                            formula
 
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
 
Not only take something from this website to enhance your knowledge.
Please, also give some feedback to the author to improve the performance.
 
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